Prepare the ConfigKit v0.10.0 release

AGENTS.md

@@ -1,5 +1,25 @@
-Please review `docs/development.md` for initial orientation in this repository
-and follow its task-specific reading guide.
+<!-- codebase-memory-mcp:start -->
+# Codebase Knowledge Graph (codebase-memory-mcp)
 
-Review and follow `docs/policy/agents.md` before recommending, planning, or
-implementing any changes to this repository.
+This project uses codebase-memory-mcp to maintain a knowledge graph of the codebase.
+ALWAYS prefer MCP graph tools over grep/glob/file-search for code discovery.
+
+## Priority Order
+1. `search_graph` — find functions, classes, routes, variables by pattern
+2. `trace_path` — trace who calls a function or what it calls
+3. `get_code_snippet` — read specific function/class source code
+4. `query_graph` — run Cypher queries for complex patterns
+5. `get_architecture` — high-level project summary
+
+## When to fall back to grep/glob
+- Searching for string literals, error messages, config values
+- Searching non-code files (Dockerfiles, shell scripts, configs)
+- When MCP tools return insufficient results
+<!-- codebase-memory-mcp:end -->
+
+Start with `docs/development.md` for orientation and use its policy reading guide
+to select the policies applicable to the task. Do not read the entire suite by
+default.
+
+Read and follow `docs/policy/agents.md` before recommending, planning, or
+implementing repository changes.

COPYRIGHT

@@ -18,3 +18,8 @@ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
 GNU Lesser General Public License for more details.
 
 Third-party code and assets are subject to their respective license terms.
+
+Policy documents adapted from Standard Repository Policies, the root AGENTS.md
+orientation, and the Policy Reading Guide in docs/development.md remain licensed
+under CC-BY-SA-4.0. See docs/oss/attribution.md for the affected material,
+upstream credit, and license links.

README.md

@@ -5,18 +5,50 @@ An opinionated Go library for applications that use YAML configuration files.
 Linux is release-validated; macOS support is best-effort. See the
 [platform support policy](docs/policy/release.md#platform-support) for details.
 
-ConfigKit's initial loader accepts one strict YAML
-source (or explicit defaults-only input), optionally traverses explicit path and glob
-imports, strictly composes their disjoint definitions, applies typed defaults, and
-can overlay one selected fixed overlay and check an application schema version. It
-returns detached metadata and safe diagnostics.
+ConfigKit's simple `Load` accepts one strict YAML source (or explicit
+defaults-only input). `LoadLayered` additionally combines explicit lower-priority
+source groups with an independently selected main input. Sources can be host
+files, native `fs.FS` files, labeled bytes or readers, or snapshotted mappings.
+Enabled explicit imports compose strictly within their group; precedence
+between groups combines mappings recursively. Both entry points return a complete,
+validated configuration with detached metadata and safe diagnostics.
 Applications may perform audited defaulting and normalization through a resolver,
 then report domain errors and warnings through read-only semantic validation. Secret
 tags and a path predicate drive deterministic redacted effective YAML. Typed secret
 references resolve environment names before validation, and explicit
 secrets-directory bootstrap is available as a separate startup operation. Explicit
-CLI override records apply above overlays. Value explanation is available through
-detached structured records and deterministic redacted output.
+CLI override records apply after inheritance and typed decoding, before application
+resolution. Value explanation is available through
+detached structured records and deterministic redacted output. Built-in
+`extends` relationships let a mapping inherit from a named sibling during the
+same load, retaining explicit presence and source/derivation history. The root
+`Diff` API compares frozen effective values from two successful same-type loads;
+the [configuration contract](docs/config.md#effective-configuration-diffs) and
+[consumer guide](docs/consumers/README.md#effective-configuration-diffs) describe
+its safe changed-region records and maintained workflows.
+
+Sources can also be explicitly placed as sequence items. Configuration
+declarations and application registrations can give selected sequences scalar
+identities and choose how they combine across precedence and inheritance.
+Strict peers combine distinct records, while higher-priority collections can
+replace, append, or upsert whole records. See the
+[sequence contract](docs/config.md#strict-document-composition),
+[maintained catalog examples](docs/consumers/README.md#identified-prompt-sequences),
+and [ADR 0017](docs/adr/0017-collection-sequence-policy.md).
+
+Imports are also explicit: a source may name files, search declared directories,
+or select files with path globs. Applications can set load-wide import defaults
+while keeping declaration-specific exceptions. Files are acquired in authored
+declaration order; dependency-ready composition uses a shared stable scheduler.
+ConfigKit does not search conventional application paths implicitly. See the
+[import contract](docs/config.md#explicit-imports), [consumer examples](docs/consumers/README.md),
+and [ADR 0015](docs/adr/0015-shared-dependency-ready-ordering.md) and
+[ADR 0016](docs/adr/0016-independent-import-controls.md).
+
+Main-file discovery is explicit too: applications choose and order `Search`
+descriptions and pass `SearchConfig` to the existing load APIs. See the
+[discovery contract](docs/config.md#configuration-discovery), [consumer guide](docs/consumers/README.md#explicit-main-file-discovery),
+and [ADR 0019](docs/adr/0019-explicit-configuration-discovery.md).
 
 ```go
 type Config struct {
@@ -33,14 +65,49 @@ func ReadConfig(path string) (Config, error) {
 }
 ```
 
-The [configuration contract](docs/config.md) describes implemented behavior. The
-[consumer adoption guide](docs/consumers/README.md) provides maintained Narratio-,
-Notarius-, WeatherReporter-, and Seriatim-shaped examples and migration guidance.
-The [deferred scope](docs/roadmap/deferred.md) records deliberate exclusions. See the
-[development guide](docs/development.md) for repository orientation and the
-[release procedure](docs/release.md) for maintainer-only candidate and publication
-steps.
+## Design philosophy
 
-ConfigKit is licensed under the [LGPL v3.0 or later](COPYRIGHT).
+ConfigKit favors one coherent, predictable configuration model over flexibility
+for reproducing each consumer's conventions. Its goal is to let applications
+load once, inspect where final values came from, and distinguish explicit values
+from omissions with minimal configuration bookkeeping. Applications retain their
+domain rules and execution responsibilities.
+
+Loading is synchronous and complete on return. Applications normally load once
+near startup and then use the final configuration and metadata; ConfigKit stays
+inactive until explicitly called again. Applications may initiate additional
+loads as needed. See the [loading lifecycle](docs/config.md#completion-and-resource-lifetime)
+for completion and ownership details.
+
+Within a configuration tier, independent contributions compose strictly: shared
+mappings combine, while overlapping non-mapping definitions are errors. Between
+precedence tiers, mappings combine recursively, retaining omitted lower-priority
+children; other values replace lower-priority values. The main document and its
+imports form one strictly composed tier. Explicit underlay groups sit below it
+and above typed defaults; a selected overlay applies before inheritance, while
+explicit CLI overrides apply after decoding and before application resolution.
+The [configuration contract](docs/config.md#strict-document-composition) owns
+the detailed combination rules and input-specific constraints. Declared or
+registered collections combine distinct identified records within strict tiers
+and use their selected operation at precedence boundaries; other sequences keep
+their strict-conflict and whole-value-replacement behavior.
+
+The [architecture goals](docs/policy/architecture.md#success-criteria) explain
+these priorities and how genuine new needs can justify extending the shared
+model. The [future feature list](docs/roadmap/future.md) preserves candidates for
+consideration in future releases.
+
+The [configuration contract](docs/config.md) describes implemented behavior,
+including [input destinations](docs/config.md#input-destinations). The
+[consumer adoption guide](docs/consumers/README.md) provides maintained simple,
+layered, mounted-collection, and identified-prompt examples alongside the
+migration shapes. Input placement decisions are recorded in
+[ADR 0011](docs/adr/0011-input-destinations.md) and sequence placement and
+composition in [ADR 0014](docs/adr/0014-sequence-placement-and-composition.md).
+See the [development guide](docs/development.md) for repository orientation and
+the [release procedure](docs/release.md) for maintainer-only candidate and
+publication steps.
+
+ConfigKit code is licensed under the [LGPL v3.0 or later](COPYRIGHT).
 
 [Open Source attribution notices](docs/oss/attribution.md) are available.

conversion.go

@@ -43,16 +43,125 @@ func toEngineLocations(values []Location) []engine.Location {
 	return result
 }
 func fromEngineSourceInfo(value engine.SourceInfo) SourceInfo {
-	return SourceInfo{ID: value.ID, Label: value.Label, Path: value.Path, Layer: Layer(value.Layer), ImportedFrom: fromEngineLocationPointer(value.ImportedFrom)}
+	return SourceInfo{
+		ID: value.ID, Label: value.Label, Path: value.Path, Destination: fromEnginePath(value.Destination),
+		PlacementMode:         PlacementMode(engine.SourceInfoPlacementModeForFacade(value)),
+		DestinationUnresolved: engine.SourceInfoDestinationUnresolvedForFacade(value),
+		Layer:                 Layer(value.Layer), Kind: SourceKind(value.Kind), UnderlayIndex: value.UnderlayIndex,
+		ImportedFrom: fromEngineLocationPointer(value.ImportedFrom), VersionCheck: fromEngineSourceVersionCheck(value.VersionCheck),
+		ImportSelections: fromEngineImportSelections(engine.SourceInfoImportSelectionsForFacade(value)),
+	}
 }
 func toEngineSourceInfo(value SourceInfo) engine.SourceInfo {
-	return engine.SourceInfo{ID: value.ID, Label: value.Label, Path: value.Path, Layer: engine.Layer(value.Layer), ImportedFrom: toEngineLocationPointer(value.ImportedFrom)}
+	result := engine.SourceInfo{
+		ID: value.ID, Label: value.Label, Path: value.Path, Destination: toEnginePath(value.Destination),
+		Layer: engine.Layer(value.Layer), Kind: engine.SourceKind(value.Kind), UnderlayIndex: value.UnderlayIndex,
+		ImportedFrom: toEngineLocationPointer(value.ImportedFrom), VersionCheck: toEngineSourceVersionCheck(value.VersionCheck),
+	}
+	result = engine.SourceInfoWithImportSelections(result, toEngineImportSelections(value.ImportSelections))
+	return engine.SourceInfoWithPlacement(result, uint8(value.PlacementMode), value.DestinationUnresolved)
+}
+
+func fromEngineImportSelections(values []engine.ImportSelectionForFacade) []ImportSelection {
+	if values == nil {
+		return nil
+	}
+	result := make([]ImportSelection, len(values))
+	for index, value := range values {
+		result[index] = ImportSelection{
+			Path: fromEnginePath(value.Path), Location: fromEngineLocation(value.Location),
+			Selector: ImportSelector(value.Selector), Outcome: ImportSelectionOutcome(value.Outcome),
+		}
+	}
+	return result
+}
+
+func toEngineImportSelections(values []ImportSelection) []engine.ImportSelectionForFacade {
+	if values == nil {
+		return nil
+	}
+	result := make([]engine.ImportSelectionForFacade, len(values))
+	for index, value := range values {
+		result[index] = engine.ImportSelectionForFacade{
+			Path: toEnginePath(value.Path), Location: toEngineLocation(value.Location),
+			Selector: string(value.Selector), Outcome: string(value.Outcome),
+		}
+	}
+	return result
+}
+
+func toEngineImportDefaults(value ImportDefaults) engine.ImportDefaults {
+	return engine.ImportDefaults{
+		Required:  cloneImportDefaultBool(value.Required),
+		Follow:    cloneImportDefaultBool(value.Follow),
+		Hidden:    cloneImportDefaultBool(value.Hidden),
+		Recursive: cloneImportDefaultBool(value.Recursive),
+		Pattern:   cloneImportDefaultStrings(value.Pattern),
+	}
+}
+
+func cloneImportDefaultBool(value *bool) *bool {
+	if value == nil {
+		return nil
+	}
+	cloned := *value
+	return &cloned
+}
+
+func cloneImportDefaultStrings(values []string) []string {
+	if values == nil {
+		return nil
+	}
+	cloned := make([]string, len(values))
+	copy(cloned, values)
+	return cloned
+}
+
+func fromEngineSourceVersionCheck(value *engine.SourceVersionCheck) *SourceVersionCheck {
+	if value == nil {
+		return nil
+	}
+	return &SourceVersionCheck{
+		Path:     fromEnginePath(value.Path),
+		Version:  Version{Present: value.Version.Present, Null: value.Version.Null, Text: value.Version.Text},
+		Location: fromEngineLocationPointer(value.Location), Redacted: value.Redacted,
+	}
+}
+func toEngineSourceVersionCheck(value *SourceVersionCheck) *engine.SourceVersionCheck {
+	if value == nil {
+		return nil
+	}
+	return &engine.SourceVersionCheck{
+		Path:     toEnginePath(value.Path),
+		Version:  engine.Version{Present: value.Version.Present, Null: value.Version.Null, Text: value.Version.Text},
+		Location: toEngineLocationPointer(value.Location), Redacted: value.Redacted,
+	}
 }
 func fromEngineOrigin(value engine.Origin) Origin {
-	return Origin{Layer: Layer(value.Layer), Locations: fromEngineLocations(value.Locations), Operation: ChangeKind(value.Operation)}
+	result := Origin{Layer: Layer(value.Layer), Locations: fromEngineLocations(value.Locations), Operation: ChangeKind(value.Operation)}
+	if value.Inheritance != nil {
+		result.Inheritance = make([]InheritanceStep, len(value.Inheritance))
+		for index, step := range value.Inheritance {
+			result.Inheritance[index] = InheritanceStep{
+				From: fromEnginePath(step.From), To: fromEnginePath(step.To), Reference: fromEnginePath(step.Reference),
+				Locations: fromEngineLocations(step.Locations),
+			}
+		}
+	}
+	return result
 }
 func toEngineOrigin(value Origin) engine.Origin {
-	return engine.Origin{Layer: engine.Layer(value.Layer), Locations: toEngineLocations(value.Locations), Operation: engine.ChangeKind(value.Operation)}
+	result := engine.Origin{Layer: engine.Layer(value.Layer), Locations: toEngineLocations(value.Locations), Operation: engine.ChangeKind(value.Operation)}
+	if value.Inheritance != nil {
+		result.Inheritance = make([]engine.InheritanceStep, len(value.Inheritance))
+		for index, step := range value.Inheritance {
+			result.Inheritance[index] = engine.InheritanceStep{
+				From: toEnginePath(step.From), To: toEnginePath(step.To), Reference: toEnginePath(step.Reference),
+				Locations: toEngineLocations(step.Locations),
+			}
+		}
+	}
+	return result
 }
 func fromEngineDiagnostic(value engine.Diagnostic) Diagnostic {
 	return Diagnostic{Code: Code(value.Code), Severity: Severity(value.Severity), Path: fromEnginePath(value.Path), Message: value.Message, Primary: fromEngineLocationPointer(value.Primary), Related: fromEngineLocations(value.Related)}

development_check_test.go

@@ -0,0 +1,110 @@
+package configkit
+
+import (
+	"bytes"
+	"os"
+	"os/exec"
+	"path/filepath"
+	"strings"
+	"testing"
+)
+
+func TestDevelopmentCheckHandlesFilenamesAndStopsOnFailure(t *testing.T) {
+	for _, scriptName := range []string{"check.sh"} {
+		t.Run(scriptName, func(t *testing.T) {
+			script, err := os.ReadFile("scripts/" + scriptName)
+			if err != nil {
+				t.Fatal(err)
+			}
+			for _, name := range []string{"success", "failed-go-check", "untracked-whitespace"} {
+				fail := name != "success"
+				t.Run(name, func(t *testing.T) {
+					root := t.TempDir()
+					bin := t.TempDir()
+					log := filepath.Join(bin, "gofmt.args")
+					calls := filepath.Join(bin, "go.calls")
+					for _, directory := range []string{"scripts", "nested"} {
+						if err := os.Mkdir(filepath.Join(root, directory), 0700); err != nil {
+							t.Fatal(err)
+						}
+					}
+					write := func(path string, data []byte, mode os.FileMode) {
+						t.Helper()
+						if err := os.WriteFile(path, data, mode); err != nil {
+							t.Fatal(err)
+						}
+					}
+					write(filepath.Join(root, "scripts", scriptName), script, 0700)
+					write(filepath.Join(root, "go.mod"), []byte("module example.invalid/check\n"), 0600)
+					write(filepath.Join(root, "go.sum"), nil, 0600)
+					write(filepath.Join(root, "obsolete.go"), []byte("package obsolete\n"), 0600)
+					files := []string{"nested/a space.go", "nested/a\nnewline.go"}
+					for _, file := range files {
+						write(filepath.Join(root, file), []byte("package example\n"), 0600)
+					}
+					if name == "untracked-whitespace" {
+						write(filepath.Join(root, "notes.md"), []byte("trailing space \n"), 0600)
+					}
+					// Isolate expensive toolchain commands: this test owns shell orchestration,
+					// not Go's compiler or the production tests exercised by the real checker.
+					write(filepath.Join(bin, "go"), []byte("#!/bin/sh\nprintf '%s/%s %s\\n' \"${GOOS-native}\" \"${GOARCH-native}\" \"$*\" >> \"$CONFIGKIT_TEST_GO_LOG\"\nif [ \"${CONFIGKIT_TEST_FAIL-}\" = yes ] && [ \"${1-}\" = test ]; then exit 37; fi\n"), 0700)
+					write(filepath.Join(bin, "gofmt"), []byte("#!/bin/sh\nprintf '%s\\000' \"$@\" > \"$CONFIGKIT_TEST_FMT_LOG\"\n"), 0700)
+					init := exec.Command("git", "init", "-q")
+					init.Dir = root
+					if out, err := init.CombinedOutput(); err != nil {
+						t.Fatalf("git init: %v %s", err, out)
+					}
+					// HEAD is required by the whitespace gate. Commit only the module baseline.
+					for _, args := range [][]string{{"add", "go.mod", "go.sum", "obsolete.go"}, {"-c", "user.name=Test", "-c", "user.email=test@example.invalid", "-c", "commit.gpgsign=false", "commit", "-qm", "Test fixture"}} {
+						cmd := exec.Command("git", args...)
+						cmd.Dir = root
+						if out, err := cmd.CombinedOutput(); err != nil {
+							t.Fatalf("git fixture: %v %s", err, out)
+						}
+					}
+					if err := os.Remove(filepath.Join(root, "obsolete.go")); err != nil {
+						t.Fatal(err)
+					}
+					cmd := exec.Command("/bin/bash", filepath.Join(root, "scripts", scriptName))
+					cmd.Env = append(os.Environ(), "PATH="+bin+string(os.PathListSeparator)+os.Getenv("PATH"), "CONFIGKIT_TEST_FMT_LOG="+log, "CONFIGKIT_TEST_GO_LOG="+calls)
+					// Log only targets selected by the script, not inherited host settings.
+					cmd.Env = append(cmd.Env, "GOOS=", "GOARCH=")
+					if name == "failed-go-check" {
+						cmd.Env = append(cmd.Env, "CONFIGKIT_TEST_FAIL=yes")
+					}
+					out, err := cmd.CombinedOutput()
+					if fail {
+						if err == nil {
+							t.Fatal("checker ignored failed Go test")
+						}
+					} else if err != nil {
+						t.Fatalf("checker: %v %s", err, out)
+					}
+					arguments, err := os.ReadFile(log)
+					if err != nil {
+						t.Fatal(err)
+					}
+					parts := bytes.Split(arguments, []byte{0})
+					for _, file := range files {
+						found := false
+						for _, arg := range parts {
+							if string(arg) == file {
+								found = true
+							}
+						}
+						if !found {
+							t.Fatalf("filename was split: %q", file)
+						}
+					}
+					invoked, err := os.ReadFile(calls)
+					if err != nil {
+						t.Fatal(err)
+					}
+					if fail && strings.Contains(string(invoked), "vet ./...") {
+						t.Fatal("checker continued after failed test")
+					}
+				})
+			}
+		})
+	}
+}

diff.go

@@ -0,0 +1,53 @@
+package configkit
+
+import "gitea.maximumdirect.net/eric/ConfigKit/internal/engine"
+
+// Difference describes one canonical changed region between two successful
+// loads. Left is the earlier value and Right is the later value. Each snapshot
+// is detached; Present distinguishes absence from an explicit null, and
+// Redacted reports whether combined sensitivity affected that side. Mappings
+// are compared recursively, while sequences are reported as atomic values.
+// Records are ordered by canonical JSON pointer. HiddenChanged indicates that
+// a value concealed by combined sensitivity changed, without revealing which
+// concealed member changed.
+type Difference struct {
+	Path          Path
+	Left          ValueSnapshot
+	Right         ValueSnapshot
+	HiddenChanged bool
+}
+
+// Diff compares the frozen effective values of two successful loads of the
+// same configuration type. It does not reread sources, environment variables,
+// or rerun defaults or resolvers. Equal values produce no records even when
+// their sources, defaults, or resolution histories differ. Credential contents
+// are not compared: typed secret references compare by reference name only.
+//
+// Both results must be non-nil successful loads with inspection state; nil or
+// zero results return an error and no records. Load errors are returned by
+// Load, so callers must handle those before calling Diff. Snapshots are safe
+// for presentation but are not a complete reloadable configuration.
+func Diff[T any](left, right *Result[T]) ([]Difference, error) {
+	var leftInspection, rightInspection *engine.Inspection
+	if left != nil {
+		leftInspection = left.inspection
+	}
+	if right != nil {
+		rightInspection = right.inspection
+	}
+
+	values, err := engine.Diff(leftInspection, rightInspection)
+	if err != nil {
+		return nil, err
+	}
+	differences := make([]Difference, len(values))
+	for index, value := range values {
+		differences[index] = Difference{
+			Path:          fromEnginePath(value.Path),
+			Left:          fromEngineValueSnapshot(value.Left),
+			Right:         fromEngineValueSnapshot(value.Right),
+			HiddenChanged: value.HiddenChanged,
+		}
+	}
+	return differences, nil
+}

discovery.go

@@ -0,0 +1,90 @@
+package configkit
+
+import "gitea.maximumdirect.net/eric/ConfigKit/internal/engine"
+
+// Search is an immutable ordered description of possible host-file inputs.
+// It is consumed only when passed to SearchConfig and used by a load.
+type Search struct{ value engine.Search }
+
+// FilenameGroup selects filenames in order for a directory search.
+// Construct groups with NamedFilenames, GenericFilenames, or CustomFilenames.
+type FilenameGroup struct{ value engine.FilenameGroup }
+
+// SearchOptions controls whether a search must select a file.
+type SearchOptions struct {
+	// Required reports a missing-source error if the complete search is exhausted.
+	Required bool
+}
+
+// DirectorySearchOptions selects the filename groups used by SearchDirectory.
+type DirectorySearchOptions struct {
+	// Filenames concatenates groups in order. A nil slice uses Named then Generic;
+	// a non-nil empty slice selects no filenames.
+	Filenames []FilenameGroup
+}
+
+// NamedFilenames selects <application>.yml followed by <application>.yaml.
+func NamedFilenames() FilenameGroup { return FilenameGroup{value: engine.NamedFilenames()} }
+
+// GenericFilenames selects config.yml, config.yaml, main.yml, and main.yaml.
+func GenericFilenames() FilenameGroup { return FilenameGroup{value: engine.GenericFilenames()} }
+
+// CustomFilenames selects literal filename components in the supplied order.
+// Names cannot be empty or contain a directory component.
+func CustomFilenames(names ...string) FilenameGroup {
+	return FilenameGroup{value: engine.CustomFilenames(names...)}
+}
+
+// SearchDirectory describes a search within directory. Omitted options or a nil
+// Filenames slice uses Named then Generic groups. Explicitly empty Filenames
+// selects no names and does not resolve the directory base.
+func SearchDirectory(directory string, supplied ...DirectorySearchOptions) Search {
+	options := make([]engine.DirectorySearchOptions, len(supplied))
+	for index, option := range supplied {
+		if option.Filenames == nil {
+			continue
+		}
+		options[index].Filenames = make([]engine.FilenameGroup, len(option.Filenames))
+		for groupIndex, group := range option.Filenames {
+			options[index].Filenames[groupIndex] = group.value
+		}
+	}
+	return Search{value: engine.SearchDirectory(directory, options...)}
+}
+
+// Paths describes literal host-file candidates in the supplied order.
+func Paths(paths ...string) Search { return Search{value: engine.Paths(paths...)} }
+
+// Searches concatenates descriptions in order and snapshots their entries.
+func Searches(searches ...Search) Search {
+	values := make([]engine.Search, len(searches))
+	for index, search := range searches {
+		values[index] = search.value
+	}
+	return Search{value: engine.Searches(values...)}
+}
+
+// UnixSystemDirectories describes the conventional Unix system directories.
+// Loading on an unsupported platform fails if this preset is reached.
+func UnixSystemDirectories() Search { return Search{value: engine.UnixSystemDirectories()} }
+
+// UserConfigDirectory describes searches rooted at the Go user-config directory.
+func UserConfigDirectory() Search { return Search{value: engine.UserConfigDirectory()} }
+
+// HomeDirectory describes searches rooted at the Go home directory.
+func HomeDirectory() Search { return Search{value: engine.HomeDirectory()} }
+
+// WorkingDirectory describes application-named files in the current directory.
+func WorkingDirectory() Search { return Search{value: engine.WorkingDirectory()} }
+
+// SearchConfig creates a source that selects the first matching host file when
+// consumed by Load or LoadLayered. Without Required, exhausting the search uses
+// the absent-input lifecycle. Description and option errors are reported while
+// loading.
+func SearchConfig(application string, search Search, supplied ...SearchOptions) Source {
+	options := make([]engine.SearchOptions, len(supplied))
+	for index, option := range supplied {
+		options[index] = engine.SearchOptions{Required: option.Required}
+	}
+	return Source{value: engine.SearchConfig(application, search.value, options...)}
+}

docs/adr/0005-explicit-overrides-and-safe-explanation.md

@@ -1,6 +1,8 @@
 # ADR 0005: Record explicit CLI overrides and safe value explanation
 
-Status: accepted
+Status: Partially superseded by
+[ADR 0018](0018-cli-after-structural-resolution.md) for override-before-decoding
+ordering. The remaining ownership and safe explanation decisions remain accepted.
 
 Date: 2026-09-06
 

docs/adr/0007-source-backed-underlays.md

@@ -0,0 +1,120 @@
+# ADR 0007: Add Source-Backed Underlays with Consistent Recursive Precedence
+
+## Status
+
+Proposed draft for review; its whole-sequence precedence replacement rule is
+superseded by [ADR 0017](0017-collection-sequence-policy.md). The remainder
+retains its proposed status. Completed planning and remediation records are
+preserved in Git history at `b604aa1` under `docs/roadmap/`; the
+[configuration contract](../config.md#layered-loading) owns current behavior.
+
+This extends [ADR 0001](0001-separate-composition-and-overlay.md) and preserves
+its distinction between strict composition and intentional overlay.
+
+## Date
+
+2026-09-29
+
+## Context
+
+Configuration-backed defaults provide lower-priority settings that applications
+can override. These sources carry imports, locations, and relative-resource
+contexts. Integrating them into ConfigKit's loading lifecycle gives their values
+the same presence tracking and inspectable provenance as other configuration
+inputs.
+
+The [architecture goals](../policy/architecture.md#success-criteria) prioritize
+one coherent, predictable configuration model with consistent rules across
+source representations and loading interfaces. Consumers should load once,
+receive a complete validated configuration, and inspect its final values' origins.
+Reducing integration code is important subject to those principles.
+
+## Decision
+
+### Add underlays to the existing precedence model
+
+Introduce explicitly supplied source-backed underlays between typed defaults
+and main configuration. The proposed precedence, from lowest to highest, is:
+
+**Typed application defaults < source underlays < strictly composed main
+configuration < selected overlay < explicit CLI overrides.**
+
+Typed defaults remain the Go-value baseline. Underlays supply lower-priority
+configuration with source provenance and, where applicable, imports and resource
+context. This ordering describes value precedence; typed defaults fill fields
+absent from the assembled input under the existing defaulting rules.
+
+Preserve strict composition of the main document and its imports before applying
+the resulting configuration over underlays. Independent contributions within an
+underlay tier also compose strictly. Explicitly ordered tiers express intentional
+precedence. Strict composition reports conflicting contributions within each tier.
+
+Across precedence tiers, reuse the existing recursive mapping-overlay semantics.
+Omitted children retain lower-priority input; existing scalar, sequence, null,
+and cross-kind replacement semantics remain unchanged. Reusing these operations
+keeps the combination rules consistent across the loading model.
+
+### Keep source representation separate from composition semantics
+
+Native `fs.FS` and programmatic inputs join the shared loading model.
+Equivalent inputs using the same
+operation have the same presence and precedence semantics regardless of medium.
+Programmatic values enter directly as labeled configuration sources.
+
+Retain the contributing source's identity and resource context through layering.
+A retained underlay value keeps its originating source's resource context.
+Consumers remain responsible for opening and interpreting their domain resources
+under the supplied filesystem's lifetime and access semantics. Exact
+context-access and input APIs remain roadmap decisions.
+
+### Deliver one final configuration and its inspection metadata
+
+Assemble effective input, then run the typed loading lifecycle once for the load.
+Preserve explicit zero,
+false, empty, and null input versus omission through configuration and metadata
+together.
+
+Extend existing provenance and history through underlays, defaults, and recorded
+application resolution. The returned result includes the completed combination,
+defaulting, and provenance work. Domain resolution and validation
+remain application-owned within the recorded lifecycle, consistent with
+[ADR 0003](0003-preserve-presence-and-resolution-history.md).
+
+Preserve the existing opt-in schema-version ownership, path protections, and
+check timing before precedence
+assembly and typed decoding. The roadmap owns how layered input identifies that
+owner when version checking is configured.
+
+Favor near-linear processing in input, retained history, and output size through
+incremental assembly of load-owned state. This is an engineering objective
+subordinate to clarity and semantic consistency. Preserve the root-owned facade and
+private implementation boundary established by [ADR 0006](0006-public-facade.md).
+
+## Alternatives considered
+
+- **Leave bundled defaults to consumers.** Avoids extending loading, but makes
+  consumers reproduce merging, presence tracking, and provenance reconciliation.
+  It does not meet the goal of obtaining a complete configuration in one load.
+- **Offer recursive or atomic combination per layer.** Makes both behaviors
+  explicit and could serve more consumers, but expands the semantic surface and
+  its interactions with presence and provenance without a demonstrated need that
+  outweighs a single consistent rule. A future concrete requirement may justify
+  reconsideration; this feature does not add the option.
+- **Flatten all documents into last-wins layers.** Simplifies ordering but turns
+  accidental main/import conflicts into overrides, weakening the intentional
+  distinction established by ADR 0001.
+
+## Consequences
+
+Consumers gain source-backed defaults within the shared loading lifecycle.
+Strict contributions and intentional precedence remain distinct, with consistent
+combination rules across source media. Presence and provenance remain
+part of the same loading lifecycle as the final values.
+
+Higher-priority mappings retain omitted lower-priority children, so application
+validation assesses the final combined configuration.
+
+Implementation must integrate source context and underlay history into the shared
+engine with attention to assembly and history-retention costs. Current behavior
+documentation will change when the feature lands. The roadmap retains ownership
+of the remaining API decisions.

docs/adr/0008-complete-on-return-loading.md

@@ -0,0 +1,82 @@
+# ADR 0008: Synchronous, Complete-on-Return Configuration Loading
+
+## Status
+
+Proposed draft for review. The
+[configuration contract](../config.md#completion-and-resource-lifetime) describes
+the implemented loading lifecycle and
+[source resource contexts](../config.md#source-resource-contexts).
+
+## Date
+
+2026-09-29
+
+## Context
+
+Applications need a clear point at which configuration is ready for use.
+Completing configuration processing and inspection metadata together gives
+applications a coherent result whose values and origins agree. A bounded loading
+lifecycle also makes resource ownership and startup failures straightforward to
+reason about.
+
+ConfigKit's [architecture goals](../policy/architecture.md#success-criteria)
+emphasize complete configuration, inspectable provenance, predictable behavior,
+and minimal consumer bookkeeping. Applications own their execution lifecycle and
+the timing of configuration acquisition.
+
+## Decision
+
+Make loading a synchronous, complete-on-return operation. Within each load,
+ConfigKit completes input assembly, defaulting, typed decoding, configured
+application resolution, secret lookup, validation, and snapshotting before
+returning the final configuration and metadata. Reported failures return
+diagnostics and a nil result.
+
+Release all library-owned loading handles before returning on success or failure.
+The resulting configuration and metadata are independently usable, caller-owned
+data with a retained inspection snapshot. Caller-supplied readers and filesystems
+remain under caller ownership and lifetime control.
+
+After the call completes, ConfigKit remains inactive until explicitly invoked
+again. Applications normally load once at or near startup and may initiate
+additional loads when needed. Each load follows the same lifecycle and source
+reuse contracts. Inspection, rendering, and separately requested operations run
+in response to explicit application calls.
+
+For the planned resource-context capability, retain source context as passive
+information or a borrowed caller-supplied filesystem. Subsequent resource access
+acquires its own handles with explicit ownership. This preserves a clear boundary
+between configuration completion and application resource use.
+
+These choices give consumers one completion boundary for configuration and
+provenance, predictable resource lifetimes, and control over when ConfigKit runs.
+Application callbacks remain responsible for their own effects and resources.
+
+## Alternatives considered
+
+- **Background watching or refresh.** Can automate responses to source changes,
+  but adds scheduling, shutdown, publication, and resource-lifetime concerns to
+  the library. Explicit calls keep those responsibilities with the application.
+- **Lazy completion after return.** Can defer work until particular values are
+  used, but moves configuration failures into application execution and makes
+  the readiness of values and metadata harder to establish.
+- **Transactional atomic loading.** Could imply simultaneous observation of all
+  external inputs and rollback of callback effects. Filesystems, environment
+  variables, and application callbacks do not share a transaction mechanism.
+  Synchronous completion provides the required usable-result boundary without
+  promising those external guarantees.
+- **Retain loading handles in results.** Can preserve open filesystem access,
+  but gives configuration results an ongoing resource lifecycle and cleanup
+  obligation. Passive source context supports later explicit resource access
+  while keeping loading resources scoped to the load call.
+
+## Consequences
+
+Applications can treat successful return as the point at which the final
+configuration and its metadata are ready for use. Startup loading remains simple,
+and additional loads have an explicit application-owned trigger.
+
+Configuration inspection operates on retained data. Resource access observes the
+backing resource when explicitly requested and has its own failure and ownership
+boundary. Implementations of new source kinds and layering features preserve the
+same completion boundary, including cleanup on reported load failures.

docs/adr/0009-sibling-inheritance.md

@@ -0,0 +1,82 @@
+# ADR 0009: Resolve Sibling Inheritance After Source Assembly
+
+## Status
+
+Partially superseded by [ADR 0017](0017-collection-sequence-policy.md) for
+sequence combination and the addition of identified-sequence sibling scopes,
+and [ADR 0018](0018-cli-after-structural-resolution.md) for CLI-before-inheritance
+ordering. Existing mapping-sibling scopes and the remaining ownership and
+inspection decisions remain accepted.
+
+The [configuration contract](../config.md#sibling-inheritance) owns implemented
+behavior. The completed implementation plan is preserved in Git
+history at `83c59ea`.
+
+## Date
+
+2026-09-29
+
+## Context
+
+Named configuration mappings often share settings while retaining individual
+overrides. ConfigKit already distinguishes strict composition of independent
+source contributions from recursive overlay between explicit precedence tiers.
+Doing another untracked merge in applications would lose omission, source
+context, and historical explanation information. A shared structural operation
+must preserve the same presence and provenance model as the rest of loading.
+
+Inheritance also interacts with source precedence, nested namespaces, version
+ownership, and secrets. Resolving it before source assembly would validate
+superseded references and copy values that a later tier should replace. Fully
+resolving nested relationships inside a reusable parent would bind them to the
+wrong sibling scope when copied into a child.
+
+## Decision
+
+Reserve `extends` as a built-in input key on mappings. A string names one exact
+sibling mapping; null cancels the relationship. Complete source acquisition,
+strict composition, selected overlay, and CLI precedence first. Then resolve
+each effective relationship in the parser-independent document tree, before
+typed defaults and decoding. A child recursively overlays its own payload on
+its resolved parent using the existing mapping-combination rules. This creates
+neither a source tier nor a configurable merge strategy.
+
+Resolve enclosing sibling chains before nested relationships. Reuse memoized
+parent templates with unresolved nested instructions; evaluate those instructions
+at each destination. Preserve original source applications separately from
+structural transfer/control evidence. Effective origins carry concrete
+source-to-destination derivation, and inspection projects relevant inheritance
+events between source replay and typed reconciliation. Inherited input counts as
+explicit presence, while direct replacement retains its own effective origin.
+
+The existing main-input version check remains at its original point. Reject
+structural contributions or directive consumption affecting its protected path.
+Classify sensitivity at corresponding source and destination paths and retain
+historical redaction. Secret references remain unresolved input until the
+existing lookup point. Keep all machinery behind the root-owned public facade.
+
+## Alternatives considered
+
+- **Application-owned inheritance after `Load`.** Leaves every consumer to
+  recreate ordering, presence, provenance, error reporting, and redaction after
+  ConfigKit has already declared a result complete.
+- **Resolve each source before precedence assembly.** Makes superseded
+  references active and can copy a parent definition before higher-priority
+  input finishes changing it.
+- **Resolve nested relationships in a cached parent subtree.** Shares more
+  ready-made output but binds nested sibling lookups to the parent's scope,
+  giving incorrect values at a child destination.
+- **Registered collections, configurable keywords, or multiple-parent merge
+  modes.** Increase public setup and semantic branches without a requirement
+  that warrants diverging from one structural rule.
+
+## Consequences
+
+Consumers can load a configuration once and inspect direct, inherited,
+defaulted, and application-derived values through the existing result surfaces.
+`extends` is no longer an ordinary application field, so existing configurations
+using that key as data must migrate. Expanding many children can materialize
+substantially more output than the input contains; projection and retained-history
+budgets bound that work without charging copies as newly acquired sources.
+Applications still own domain validation, entry selection, and runtime resource
+use.

docs/adr/0010-effective-configuration-diff.md

@@ -0,0 +1,99 @@
+# ADR 0010: Compare Frozen Effective Configuration Snapshots
+
+## Status
+
+Accepted and implemented. The
+[configuration contract](../config.md#effective-configuration-diffs) owns current
+behavior. Completed planning and remediation records are preserved in Git
+history at `1c2610c` under `docs/roadmap/`.
+
+## Date
+
+2026-10-09
+
+## Context
+
+Applications need to inspect how two completed configurations differ, including
+the effective impact of an overlay after defaults and application resolution.
+ConfigKit already retains canonical typed inspection snapshots, semantic paths,
+presence information, and sensitivity classification for successful loads.
+
+Extending this inspection model lets applications share configuration comparison
+and safe disclosure while keeping their presentation and domain interpretation.
+The operation should follow ConfigKit's existing equality, ownership, and secret
+boundaries so consumers can reason about loading and inspection consistently.
+
+## Decision
+
+Provide structured effective-value comparison between successful results of the
+same configuration type. Compare their retained canonical inspection snapshots
+through the root-owned public facade. Each comparison uses the completed load
+state and returns detached records with a semantic path and safe left and right
+value snapshots.
+
+Use canonical value equality and the existing structural comparison rules.
+Mappings compare recursively, sequences report atomic changes, and scalar or
+kind replacements report the affected region. Presence distinguishes additions
+and removals from explicit null. Equal effective values produce an empty diff;
+source attribution, explicit-input status, and history remain separately
+inspectable through each result. Canonical pointer ordering makes reporting
+deterministic.
+
+Detect changes before masking values. Apply sensitivity from both loads to both
+returned sides, including historical and dependency-derived classification.
+Preserve public content where the shapes permit corresponding sensitive regions
+to be identified. When a structural replacement prevents safe correspondence,
+mask the complete reported replacement region on both present sides. Absence
+retains its own representation.
+
+Keep masking and hidden-change information distinct. Each record indicates
+whether an actual change is withheld by redaction, allowing applications to
+display a changed-sensitive-value indicator even when safe snapshots render
+identically. Public-only changes alongside unchanged masked content retain that
+distinction.
+
+Typed secret references participate through their configured environment names.
+Resolved credential bytes remain behind the existing explicit secret accessor.
+The comparison uses the same frozen inspection boundary as effective rendering
+and explanation.
+
+ConfigKit owns comparison and paired safe disclosure. Applications own labels,
+layout, and rendering of the returned changed regions. Reusing the existing
+snapshot representation and engine boundary keeps the extension consistent with
+the library's established inspection model.
+
+## Alternatives considered
+
+- **Compare input text or separately rendered YAML.** Supports familiar textual
+  displays, but input text precedes composition and resolution, and independently
+  redacted output can hide changes or apply different disclosure rules. Canonical
+  comparison with paired masking represents the completed configuration.
+- **Leave comparison to applications using returned Go values.** Offers direct
+  access to application types, but duplicates structural and redaction machinery
+  and observes caller mutation. Retained inspection snapshots preserve the
+  completed load's values and established ownership boundary.
+- **Align sequence elements and return context-rich rendering data.** Enables
+  finer-grained displays, but requires additional correspondence and disclosure
+  rules. Atomic sequence records and existing value snapshots satisfy the
+  selected changed-region workflows with a smaller public model.
+- **Compare resolved credentials or retain credential-derived tokens.** Could
+  detect rotation behind an unchanged reference, but expands retained sensitive
+  state and introduces a separate trusted comparison mechanism. Reference-name
+  comparison preserves the existing inspection boundary.
+
+## Consequences
+
+Applications can compare independently loaded configurations using ConfigKit's
+shared equality, presence, and disclosure rules. Existing composition and load
+semantics continue to determine the values being compared. Caller mutation of a
+returned configuration leaves its retained comparison snapshot unchanged.
+
+Paired redaction can conceal public content within a structurally incompatible
+replacement. The changed region and hidden-change indicator still communicate
+its effective impact. Credential rotation behind an unchanged environment name
+produces equal reference values for comparison.
+
+The implementation requires operation-local disclosure preparation and focused
+coverage for presence, shape changes, historical sensitivity, and detached
+results. Applications retain control of presentation; changed-region records
+supply the safe data needed for that responsibility.

docs/adr/0011-input-destinations.md

@@ -0,0 +1,74 @@
+# ADR 0011: Place Configuration Inputs at Mapping Destinations
+
+## Status
+
+Accepted and implemented. Current placement behavior is owned by the
+[configuration contract](../config.md#input-destinations). The accepted
+relative-import extension is recorded in
+[ADR 0012](0012-relative-import-destinations.md). The completed roadmap, consumer
+request, and review records are preserved at `e4270c9` under `docs/roadmap/` in
+Git history; the original input-destination implementation plan remains at
+`315f464:docs/roadmap/implementation.md`.
+
+## Date
+
+2026-10-14
+
+## Context
+
+Consumers assembling collections of independently authored configuration
+fragments need each source to contribute beneath a selected application path.
+Requiring consumers to rewrite source documents or merge completed values would
+separate placement from ConfigKit's existing composition, precedence, source
+identity, and inspection behavior. Placement should remain part of the ordinary
+loading lifecycle and preserve the root-owned public facade.
+
+## Decision
+
+Add an optional `Destination Path` to root-owned `Input` and expose the effective
+destination on existing `SourceInfo` records. The empty path means the existing
+application root. A non-empty destination is a sequence of literal mapping keys;
+explicit sequence-index segments are invalid. Existing reserved structural keys
+remain reserved, while keys that merely contain their spelling remain ordinary
+keys.
+
+Acquire and interpret each source using its original physical identity and
+source-local directives, then place its application body before strict
+composition and the existing final lifecycle. Imported application bodies
+inherit the input destination. Placement applies to main and underlay inputs;
+ordinary root loading, selected overlays, and CLI inputs retain root placement.
+The main-owned version rule continues to check its effective application path
+at its existing lifecycle point.
+
+Placement preserves authored node locations and source identity. Introduced
+mapping structure belongs to the contributing source and uses that document's
+root location as its source-coordinate fallback. A present empty mapping
+materializes its destination; an absent `NoSource` contributes nothing. The
+result continues through the existing strict composition, overlay, inheritance,
+typed loading, diagnostics, provenance, history, sensitivity, and resource
+context mechanisms.
+
+The added exported fields preserve keyed and zero-value struct use. Callers
+using unkeyed composite literals for `Input` or `SourceInfo` must migrate to
+keyed literals. Treat this feature as minor-release work; select the version and
+document the compatibility impact during separately authorized release
+preparation, consistent with the release policy.
+
+## Alternatives considered
+
+- **Rewrite or merge sources in consumers.** This makes each consumer reproduce
+  placement, strict composition, source attribution, and inspection semantics.
+- **Add a separate loading entry point or public wrapper type.** This creates a
+  parallel API for a behavior that belongs to existing per-input loading.
+- **Load each fragment as a complete application before placement.** This runs
+  defaults, decoding, resolution, and validation on incomplete fragments rather
+  than once on the assembled application.
+
+## Consequences
+
+Consumers can assemble contributions at effective mapping paths in one ordinary
+layered load and inspect each source's placement through existing source
+records. Paths, conflicts, and later application operations use the placed
+structure while source coordinates and relative-resource contexts continue to
+identify their original sources. Public field additions require release-note
+guidance for callers using unkeyed literals.

docs/adr/0012-relative-import-destinations.md

@@ -0,0 +1,78 @@
+# ADR 0012: Place Imported Configuration at Relative Destinations
+
+## Status
+
+Accepted and implemented. The
+[configuration contract](../config.md#input-destinations) owns current behavior.
+The completed roadmap and review records are preserved at `e4270c9` under
+`docs/roadmap/` in Git history; the relative-import implementation plan remains
+at `d9f08ff:docs/roadmap/implementation.md`.
+
+## Date
+
+2026-10-14
+
+## Context
+
+ConfigKit can place an input document at a literal mapping path while retaining
+source identity, composition, and inspection in its normal loading lifecycle.
+An importing document can currently bring in other documents, but those
+contributions inherit only the importing input's destination. Consumers that
+assemble a collection therefore cannot declare the layout of imported
+fragments alongside the import itself without rewriting source documents or
+performing another merge outside ConfigKit.
+
+The extension should reuse input placement and the existing import lifecycle.
+Logical application placement must remain independent from physical path
+resolution, source identity, precedence, and resource ownership.
+
+## Decision
+
+Add an optional `destination` field to each YAML import declaration. Its value
+is a sequence of strings representing literal mapping-key segments. Omission
+and an empty sequence add no segments. A non-empty destination appends to the
+effective destination of the immediately importing document; nested imports
+continue from the resulting child destination. Every match of one glob
+declaration receives the same computed destination.
+
+Use the existing input-destination validation and reserved-key rules. Do not
+interpret destination segments as filesystem paths, separators, sequence
+indices, or root-reset instructions. Physical import paths continue to resolve
+from their declaring source under existing containment rules.
+
+Imports remain in their existing strict-composition group. A destination does
+not grant precedence, bypass cycle or repeated-source rules, or change source
+identity. Existing placement, version ownership, source records, diagnostics,
+resource contexts, inheritance, history, and inspection mechanisms continue to
+govern the placed contributions. No public Go entry point or independent
+specification-header behavior is introduced.
+
+This is additive YAML functionality and is minor-release work. Version
+selection, release notes, roadmap retirement, and publication remain separate
+release-preparation work.
+
+## Alternatives Considered
+
+- **Require complete application-root destinations on every import.** This
+  avoids inherited context but repeats collection prefixes in nested source
+  declarations and does not express placement relative to the importing
+  document.
+- **Encode destinations as dotted or slash-delimited strings.** This introduces
+  separator and escaping rules even though existing paths already represent
+  literal mapping keys as segments.
+- **Rewrite or merge imported documents in consumers.** This duplicates source
+  placement, strict composition, attribution, and inspection behavior outside
+  ConfigKit's loading lifecycle.
+- **Add independent specification headers or collection-specific validation.**
+  These are separate design questions and are not required to declare relative
+  placement.
+
+## Consequences
+
+Import declarations can describe the logical placement of their contributions
+while preserving the physical source and existing composition lifecycle.
+Placement is immediate-parent-relative, so nested imports accumulate their
+declared segments and sibling declarations remain independent. The feature is
+implemented behind the existing public loading surface; detailed validation,
+diagnostic, accounting, and inspection requirements are tracked by the
+implementation roadmap.

docs/adr/0013-shared-source-version-checks.md

@@ -0,0 +1,92 @@
+# ADR 0013: Check Source Versions with One Shared Policy
+
+## Status
+
+Accepted and implemented. The
+[configuration contract](../config.md#shared-source-version-checks) owns current
+behavior. The completed roadmap, implementation plan, consumer request, and
+resolved review findings are preserved at `e4270c9` under `docs/roadmap/` in
+Git history; the [development guide](../development.md#baseline-validation)
+provides retrieval examples.
+
+## Date
+
+2026-10-15
+
+## Context
+
+Applications that assemble one configuration from independently authored
+documents need a way to require that each contributing document declares a
+version accepted by the application's existing `Definition.Version` checker.
+Checking only the eventual composed value lets another source hide a rejected
+declaration, while separate consumer-side parsing duplicates ConfigKit's source
+handling and diagnostics.
+
+The extension must preserve one application-owned acceptance policy and the
+existing loading lifecycle. Source declarations are compatibility evidence, not
+independent fragment schemas or values to compare for equality. Existing
+composition, placement, precedence, source identity, diagnostics, and
+sensitivity rules remain authoritative.
+
+## Decision
+
+Provide a load-wide source-version mode for ordinary and layered loading. The
+zero-value mode preserves current behavior. The enabled modes check declarations
+when present or require them, using the existing `Definition.Version` path and
+checker. Interpret the configured path relative to each participating source
+before placement or composition. Different declarations may be accepted by the
+same checker; ConfigKit adds no equality, SemVer, or expected-version rule.
+
+Apply the selected policy to the actual main document, direct underlays,
+imports, and selected overlays. Missing non-main declarations are skipped in
+if-present mode and rejected in required mode. Existing main absence behavior
+remains, with required mode additionally rejecting an absent declaration on an
+actual main document. `NoSource`, unmatched optional inputs, synthetic field
+operations, and empty groups do not become documents that need declarations.
+
+Reuse the existing version vocabulary and validation boundary: absence, null,
+exact strings, and strict decimal integers retain their established meanings;
+unsupported present values fail version-type validation. Warnings remain
+nonfatal, and source declarations do not replace final application decoding or
+domain validation.
+
+After an accepted non-main declaration is checked, consume exactly that node
+before its remaining application content is composed or overlaid. Preserve the
+main declaration and its value semantics. Keep the declaration, source-local
+path, physical location, and checked absence as detached source evidence,
+separate from effective application values and history. Apply established
+sensitivity rules to that evidence, including original mounted paths and
+ancestors; retain existing safe failure disclosure.
+
+In enabled modes, the main declaration remains source-local while its protected
+application path is derived from the main input's destination. This distinction
+does not change default-mode path interpretation or weaken protection of
+remaining payload and synthetic operations.
+
+Public option-field additions and the enabled-mode interpretation for mounted
+main inputs are compatibility considerations for separately authorized minor-
+release preparation. This decision does not select a release version or
+authorize release notes or publication.
+
+## Alternatives Considered
+
+- **Check only the final composed value.** Later sources can hide an earlier
+  rejected declaration, so this does not validate every contributing document.
+- **Let consumers parse and check each source.** This duplicates acquisition,
+  source attribution, safe diagnostics, and lifecycle coordination in every
+  application.
+- **Require declarations to be equal or impose a universal version grammar.**
+  Consumers already own the acceptance policy; ConfigKit need not invent an
+  expected value or a domain-specific compatibility rule.
+- **Keep accepted non-main declarations in application payload.** A selected
+  source-local declaration is metadata for this policy and cannot also remain
+  an ordinary field at the same path without ambiguity.
+
+## Consequences
+
+Consumers can apply one existing version policy across contributing documents
+and select gradual or required adoption per load. Accepted non-main headers no
+longer participate in application composition; their inspectable evidence is
+kept separate and subject to sensitivity classification. Default callers retain
+current behavior. The implementation plan records the concrete API names,
+integration order, and validation evidence.

docs/adr/0014-sequence-placement-and-composition.md

@@ -0,0 +1,81 @@
+# ADR 0014: Place and Compose Sequence Items Explicitly
+
+## Status
+
+Partially superseded by [ADR 0017](0017-collection-sequence-policy.md) for
+identity ownership and sequence combination. Explicit source placement remains
+accepted.
+
+The [configuration contract](../config.md#strict-document-composition)
+defines implemented behavior, and the [consumer guide](../consumers/README.md#identified-prompt-sequences)
+shows the maintained example. The completed roadmap, implementation plan, and
+resolved remediation record are preserved in Git history at `008d2ba` under
+`docs/roadmap/`; see the [development guide](../development.md) for retrieval
+commands.
+
+## Date
+
+2026-10-16
+
+## Context
+
+ConfigKit strictly composes independent documents by recursively combining
+mappings and rejecting other overlapping values. This makes two independently
+authored sequence fragments conflict, even when their records are distinct.
+Precedence assembly has a different purpose: a higher-priority present sequence
+replaces the lower-priority sequence as one value. Those existing rules are
+predictable, but they do not express the separate operation of collecting
+independent records while rejecting duplicate identities.
+
+Likewise, mapping destinations place a source beneath literal mapping keys, but
+there is no explicit way to state that a source mapping represents one item in a
+sequence. Inferring that intent from document shape or fields would make source
+meaning implicit and change existing placement behavior.
+
+## Decision
+
+Keep mapping placement as the zero-value behavior and add an explicit item
+placement choice for a source whose mapping should become one element at a
+non-root sequence destination. Item placement provides structure only; it does
+not infer or synthesize identity values.
+
+Allow a definition to register literal mapping paths and one literal identity
+field for sequences at those paths. Within each strict composition tier, a
+registered sequence accepts mapping records with a present string identity,
+appends distinct records in contribution order, and rejects repeated exact
+identity strings. Identical registrations coalesce; conflicting identity fields
+for the same path are invalid. Registration does not recursively select paths
+inside sequence records.
+
+Keep precedence assembly unchanged. A present higher-priority sequence replaces
+the lower-priority value wholesale, including at a registered path. Registration
+changes strict composition only; it does not turn precedence into append or
+identity-based merging.
+
+This decision preserves ConfigKit's distinction between independent
+same-priority contributions and intentional precedence. Explicit source
+placement and definition-owned composition policy make the two required choices
+visible while keeping the existing zero-value load behavior.
+
+## Alternatives Considered
+
+- **Infer item placement from a source mapping or identity field.** Shape-based
+  inference would make ordinary mapping placement depend on document contents
+  and would leave the intended destination ambiguous.
+- **Append all overlapping sequences during strict composition.** This would
+  change existing conflict semantics at unregistered paths and would not detect
+  duplicate records.
+- **Merge matching records recursively by identity.** This would add a second
+  recursive merge rule with different conflict and precedence behavior from
+  ConfigKit's existing mapping composition and overlay operations.
+- **Use identity to merge sequences across precedence tiers.** This would
+  change established whole-value replacement semantics and conflate strict
+  composition with precedence.
+
+## Consequences
+
+Consumers can explicitly place mappings as sequence items and opt selected
+sequences into duplicate-rejecting strict composition. Unregistered sequences
+retain their current strict-conflict behavior, and higher-priority sequences
+continue to replace lower-priority ones. The implementation plan owns the exact
+API, YAML syntax, diagnostics, and implementation status.

docs/adr/0015-shared-dependency-ready-ordering.md

@@ -0,0 +1,68 @@
+# ADR 0015: Share Dependency-Ready Ordering Across Imports and Inheritance
+
+## Status
+
+Accepted. Implemented behavior is described in the
+[configuration contract](../config.md#explicit-imports) and
+[internal import overview](../internal/imports.md).
+
+## Date
+
+2026-10-19
+
+## Context
+
+Imports and sibling inheritance both resolve relationships between configuration
+contributions. Their existing resolvers use different traversal rules, making
+ordering depend on which mechanism expresses a dependency. Ordering affects
+sequence contributions, provenance, and diagnostics, so a consistent rule is
+part of ConfigKit's configuration model.
+
+The resolvers also serve distinct purposes. Imports strictly compose sources;
+inheritance overlays a child on its resolved parent after source assembly.
+Item-local contributions and nested inheritance introduce scope boundaries that
+resolution must preserve.
+
+## Decision
+
+ConfigKit owns one shared dependency-ready scheduler for imports and sibling
+inheritance. Both resolvers use Kahn's algorithm with a stable ordering key,
+selecting the smallest currently eligible node after its dependencies have
+completed. The shared scheduler owns eligibility, deterministic tie-breaking,
+and dependency-cycle identification. Each resolver owns construction of its
+dependency relationships and application of its domain operations.
+
+Apply the common scheduling rule within the scopes where dependencies are
+available. Complete item-local contributions before item placement and resolve
+enclosing inheritance before relationships in the resulting nested scopes.
+Source discovery supplies the import graph; the scheduler determines resolution
+order.
+
+Strict composition, inheritance overlay, and precedence tiers retain their
+existing ownership and meanings under [ADR 0001](0001-separate-composition-and-overlay.md).
+The lifecycle and scope decisions in
+[ADR 0009](0009-sibling-inheritance.md) continue to govern inheritance. Import
+admission retains its cycle and repeated-source rules.
+
+## Alternatives Considered
+
+- **Deterministic depth-first postorder.** Keeps dependency branches together,
+  but gives traversal branch selection an additional role in ordering.
+- **Dependency rounds.** Groups nodes by readiness rounds, but delays newly
+  eligible nodes until the current round finishes.
+- **Descending longest-path depth.** Prioritizes the furthest dependencies,
+  but adds distance from the root as an ordering policy.
+- **Separate resolver algorithms.** Allows local specialization, but leaves
+  consumers and maintainers with different rules for analogous dependencies.
+
+## Consequences
+
+Both resolvers follow one deterministic ordering model and share responsibility
+for maintaining that model. Resolver-specific scopes, combination semantics,
+and source-admission rules remain explicit at their integration boundaries.
+
+Independent branches may interleave as nodes become eligible. Adopting this
+rule changes existing traversal-dependent sequence positions and reporting
+order, requiring coordinated review of source assembly, provenance, and
+inheritance behavior. The configuration contract owns the implemented ordering
+details.

docs/adr/0016-independent-import-controls.md

@@ -0,0 +1,83 @@
+# ADR 0016: Separate Import Selection, Traversal, and Presence Requirements
+
+## Status
+
+Accepted. Implemented behavior is described in the
+[configuration contract](../config.md#explicit-imports), the
+[public API declarations](../../lifecycle.go), and the
+[internal import overview](../internal/imports.md).
+
+## Date
+
+2026-10-19
+
+## Context
+
+Consumers assemble configurations from named files and collections whose layout
+varies between installations. Simple imports should require little setup, while
+larger collections need control over discovery, recursion, filtering, and
+required contributions. Combining those choices implicitly makes declarations
+harder to interpret and pushes source-selection work into applications.
+
+Discovery can also reach a candidate through overlapping searches or encounter
+different names for one canonical source. Selection and source admission need
+distinct identities to support useful search unions while preserving ConfigKit's
+existing source-integrity rules.
+
+## Decision
+
+ConfigKit owns import discovery and selection within its source-loading
+lifecycle. Support explicit files, directory searches, and path globs as
+distinct selection forms. Keep traversal, filename filtering, and presence
+requirements independently expressible. Discovery determines the selected
+contributions; the shared scheduler in
+[ADR 0015](0015-shared-dependency-ready-ordering.md) determines their resolution
+order.
+
+Use optional-by-default imports with explicit requiredness controls. Selected
+sources remain subject to ConfigKit's validity, containment, resource, and
+composition contracts. This applies the library's
+[simplicity and defaults principles](../policy/architecture.md#simplicity-defaults-and-explicit-controls)
+to import absence while retaining meaningful errors for invalid contributions.
+
+Applications own their selected import defaults. Authored declaration values
+take precedence over application defaults, which take precedence over library
+defaults. Each declaration resolves applicable controls independently,
+including declarations in imported sources. This gives applications a shared
+baseline while preserving explicit choices in individual declarations.
+
+Keep declaration-local candidate identity separate from canonical source
+identity. Search unions coalesce repeated candidate paths within a source
+namespace before symlink resolution; filename filtering uses the selected or
+discovered name. Source admission continues to use canonical identity and the
+existing repeated-source rules. Distinct aliases retain their separate
+inclusion routes.
+
+## Alternatives Considered
+
+- **Use path globs for all discovery.** Offers one selection form, but makes
+  collection traversal depend on path-pattern structure and complicates
+  independently controlling recursion and filename filtering.
+- **Offer only explicit files and directory searches.** Reduces the selector
+  vocabulary, but moves wildcard directory selection into repeated declarations
+  or application-side discovery.
+- **Require every import by default.** Detects absent contributions immediately,
+  but requires repeated opt-outs for installations with optional components.
+- **Make application settings override authored declarations.** Provides central
+  enforcement, but prevents declarations from expressing local exceptions.
+- **Deduplicate selections globally by canonical source identity.** Coalesces
+  aliases and separate inclusion routes, but changes the existing repeated-source
+  contract and obscures independently authored contributions.
+
+## Consequences
+
+Consumers can express simple imports and more selective collection searches
+through the same loading lifecycle. Applications choose defaults and validate
+their required effective configuration; ConfigKit owns consistent selection,
+source admission, composition, and inspection.
+
+Optional absence can conceal misspelled selectors, so requiredness and
+inspection provide explicit ways to detect and explain missing contributions.
+Declaration-local deduplication requires the loader to preserve candidate
+identity alongside canonical source identity. The configuration and public API
+contracts own the implemented behavior.

docs/adr/0017-collection-sequence-policy.md

@@ -0,0 +1,143 @@
+# ADR 0017: Define Identity and Merge Rules for Each Collection
+
+## Status
+
+Accepted.
+
+This supersedes the decisions about who declares identity and how
+sequences combine in [ADR 0014](0014-sequence-placement-and-composition.md),
+and the rule that inheritance always replaces sequences in
+[ADR 0009](0009-sibling-inheritance.md). It also extends that ADR's sibling
+scopes to identified sequences. Existing mapping-sibling scopes and source
+placement continue to apply. It supersedes the whole-sequence
+precedence replacement rule in the proposed
+[ADR 0007](0007-source-backed-underlays.md).
+
+## Date
+
+2026-10-22
+
+## Context
+
+ConfigKit can load separate files as records in a sequence. Applications can
+register an identity key so records with different identities combine and
+duplicates fail. However, a higher configuration layer or an inheriting mapping
+currently replaces the whole sequence. Applications that need to extend a
+catalog across layers must write their own merging code and keep source and
+history information consistent with its results.
+
+Configuration authors need to choose how records are identified and whether a
+layer adds records, updates records, or replaces the collection. Applications
+also need a way to require unique identities in the final loaded configuration.
+These rules must work consistently for imported records, inline sequences,
+overlays, and inheritance.
+
+Records in a sequence may also share settings. Authors need to reuse those
+settings through inheritance while keeping each record's own identity.
+
+## Decision
+
+ConfigKit manages identity and merge rules for each collection during loading.
+Configuration files can declare those rules for imported and inline sequences,
+including sequences in selected overlays. Applications can require a particular
+identity definition, and configuration declarations must agree with it. Source
+placement determines where each contribution enters the configuration.
+
+Keep the distinction between contributions at the same priority and overrides
+from a higher layer, as established in
+[ADR 0001](0001-separate-composition-and-overlay.md). Within one tier, records
+with distinct identities combine; duplicate identities and conflicting
+declarations fail. Determine the applicable rules before combining those
+contributions, including any identity established in lower tiers.
+
+Across layers, support three operations: replace the whole sequence, append
+records while rejecting duplicate identities, or replace whole records by
+identity (`upsert`). Source layering and sibling inheritance use the same
+operations. For inheritance, the rules at the inheriting destination determine
+which operation applies.
+
+An identified sequence is also a sibling scope for inheritance. A record may
+inherit from one other record in the same sequence, selected by its complete
+identity. Each record supplies its own identity before inheritance. The child
+keeps that identity and combines its settings with the parent's other fields,
+using the existing mapping and collection rules. Parents remain ordinary records
+subject to normal validation.
+
+Resolve these relationships after source assembly, using the same dependency
+ordering as mapping-sibling inheritance. Resolve nested relationships at each
+inheriting destination. Preserve the assembled sequence order. Whole-record
+upsert keeps its existing meaning; inheritance then uses the records that remain.
+Typed defaults, CLI overrides, and application resolution follow the lifecycle
+in [ADR 0018](0018-cli-after-structural-resolution.md).
+
+An explicitly selected operation remains in effect at its destination until a
+higher layer changes it. When no explicit operation applies, use upsert if an
+identity definition is available; otherwise replace the whole sequence. Authors
+can declare identity and an operation before supplying any records. Keep source
+acquisition order separate from layer priority and the dependency ordering
+established by [ADR 0015](0015-shared-dependency-ready-ordering.md).
+
+Rules declared inside a record belong to that record. Retaining the record
+retains its local rules; replacing it discards them. Replacing a whole collection
+can discard its previous YAML identity definition, while application requirements
+still apply. Inheritance can copy collection identity, but the inheriting
+destination chooses its operation. Application registrations continue to govern
+the paths where they were registered. The same ownership rules apply to
+declarations made before a sequence exists.
+
+Check YAML-declared identity when combining collections during source assembly
+and inheritance. Application registrations also require the final loaded
+sequences to satisfy their identity rules, including after typed defaults, CLI
+overrides, and application resolution. This guarantee checks sequences that
+exist; the application schema and validation decide whether a collection must
+exist and which value types are allowed. The guarantee applies when loading
+completes, rather than to every intermediate callback state or changes made by
+the caller afterward.
+
+Preserve explicit presence, source attribution, history, sensitivity, and
+resource context through these operations, following
+[ADR 0003](0003-preserve-presence-and-resolution-history.md). Typed defaults,
+CLI assignments, and application resolution keep their own rules for changing
+values. The public API provides registration and inspection; the implementation
+chooses how to store and track collection rules internally.
+
+## Alternatives Considered
+
+- **Keep identity application-owned and always replace sequences across layers.**
+  Keeps the current design small, but reusable catalogs require application
+  changes or custom merging code.
+- **Put merge rules on each import.** Keeps the rules beside the imported source,
+  but inline sequences and overlays need a separate way to declare them. It also
+  makes rules for a collection spread across several imports harder to reconcile.
+- **Merge individual fields of records with matching identities.** Allows partial
+  record updates, but adds rules for field conflicts and retained values.
+  Replacing the whole record makes the update's scope clear.
+- **Keep inheritance limited to mapping siblings.** Keeps parent lookup simpler,
+  but authors of sequence records must duplicate shared settings or applications
+  must implement inheritance themselves. Collection identity provides a way to
+  select a parent within the existing loading process.
+- **Check every YAML identity again at the end of loading.** Gives YAML declarations
+  authority over values changed by defaults, CLI assignments, and application
+  resolution. This extends the lifetime of those declarations; application
+  registration provides that final guarantee when needed.
+
+## Consequences
+
+Consumers can build and customize catalogs in one load while retaining useful
+inspection information. Configuration authors choose how collections combine
+within application requirements. Duplicate identities among contributions at
+the same priority remain errors.
+
+Existing registered collections use upsert across layers by default unless an
+explicit operation selects otherwise. Correct loading now requires tracking
+which declarations still apply as records are replaced, copied, or moved to new
+positions. Lower-tier identity must be available before combining higher-tier
+contributions.
+
+Record inheritance also requires parent lookup by identity and checking for
+missing parents and cycles. Copied settings retain the same source, history,
+and sensitivity information as mapping-sibling inheritance.
+
+The [configuration contract](../config.md#strict-document-composition) defines
+declaration syntax, identity comparison, omission and empty-value behavior, and
+diagnostics for the implemented feature.

docs/adr/0018-cli-after-structural-resolution.md

@@ -0,0 +1,84 @@
+# ADR 0018: Apply CLI Overrides After Inheritance and Decoding
+
+## Status
+
+Accepted.
+
+This supersedes the rule that CLI overrides apply before decoding in
+[ADR 0005](0005-explicit-overrides-and-safe-explanation.md) and the
+rule that they apply before inheritance in [ADR 0009](0009-sibling-inheritance.md).
+Their remaining ownership, inheritance scope, and safe inspection decisions
+continue to apply.
+
+## Date
+
+2026-10-22
+
+## Context
+
+Explicit command-line values are the operator's highest-priority input. If they
+apply before inheritance, a sequence supplied as a replacement could gain
+inherited records afterward. Its final contents would then differ from the
+operator's assignment.
+
+The application also needs these values when it fills missing settings,
+normalizes values, or computes derived settings. ConfigKit needs a clear loading
+order that preserves both CLI precedence and the application's role in resolving
+the final configuration.
+
+## Decision
+
+ConfigKit uses this loading order:
+
+1. Combine sources within tiers and apply precedence between layers.
+2. Resolve sibling inheritance, apply typed defaults, and decode the configuration
+   into the application's types.
+3. Apply explicit CLI overrides and check them against the application schema.
+4. Run application resolution using the overridden configuration.
+5. Look up effective secret references, validate the final configuration, and
+   return it.
+
+CLI overrides are the highest-priority input to application resolution. A CLI
+sequence replaces the whole sequence; mappings combine recursively. Collection
+merge rules apply during the earlier source and inheritance steps. Inheritance
+and typed defaulting do not run again after CLI overrides.
+
+Keep track of which values were explicitly supplied and which CLI input supplied
+them. Applications continue to parse command-line arguments; ConfigKit applies
+and validates the overrides and makes their effects inspectable. Reject
+structural directives in override paths and values, so instructions such as
+inheritance relationships remain part of source processing.
+
+Application resolution keeps its existing rules for defaults and recorded
+changes under [ADR 0003](0003-preserve-presence-and-resolution-history.md).
+It receives CLI values together with their presence and source information.
+Defaults that only fill missing settings preserve explicit CLI values.
+Application normalization and derived-value calculations can still change them,
+with those changes recorded. Secret lookup and final validation use the resulting
+configuration.
+
+## Alternatives Considered
+
+- **Apply CLI overrides before inheritance.** Preserves existing ordering, but
+  later merging needs special handling to preserve CLI replacement intent while
+  still combining ordinary source contributions.
+- **Apply CLI overrides after inheritance but before typed decoding.** Allows an
+  override to fix a source value that would otherwise fail decoding, but leaves
+  typed defaulting after the operator's assignment. Completing defaulting and
+  decoding first gives CLI overrides an already resolved configuration to modify.
+- **Apply CLI overrides after application resolution.** Applies assignments after
+  the application's changes, but derived settings still reflect earlier values
+  unless resolution runs again.
+
+## Consequences
+
+CLI overrides change a configuration whose inheritance and typed defaults are
+already resolved. The application can then derive settings from the operator's
+values. The final values, source information, history, and sensitivity handling
+must remain consistent throughout loading.
+
+CLI input can no longer add or cancel inheritance relationships or bypass an
+earlier error in source assembly or inheritance. It also cannot fix a value that
+fails the earlier decoding step. Semantic validation still runs after overrides
+and application resolution. The [configuration contract](../config.md#explicit-cli-overrides)
+and [consumer guidance](../consumers/README.md) describe this behavior.

docs/adr/0019-explicit-configuration-discovery.md

@@ -0,0 +1,68 @@
+# ADR 0019: Keep Configuration Discovery Explicit and Inside Loading
+
+## Status
+
+Accepted.
+
+## Date
+
+2026-10-24
+
+## Context
+
+Applications often need a small ordered convention for choosing a main
+configuration file. Keeping that choice entirely in each application repeats
+path selection and file-loading plumbing. Moving the convention into ConfigKit
+without an explicit declaration would make ordinary loads search paths that a
+consumer did not choose, obscuring both precedence and filesystem access.
+
+ConfigKit already owns synchronous source acquisition, parsing, composition,
+decoding, validation, and inspection. A selected host file can therefore enter
+that lifecycle as the existing file source, preserving its source identity,
+resource context, and diagnostics. Optional exhaustion can use the same absent
+main lifecycle as an explicitly absent source.
+
+## Decision
+
+Consumers choose and order the main-file conventions they want to use. They may
+describe literal paths, directory filename groups, and supported directory
+presets, and may mark the complete search as required. Search descriptions are
+explicit inputs to loading; no preset or convention is activated implicitly.
+
+During synchronous loading, ConfigKit resolves the description to one real host
+file or to absence before parsing. The selected file follows the existing source
+acquisition and processing rules. A selected-file access, parse, version,
+composition, decode, or validation failure is terminal and does not resume the
+search. Optional exhaustion shares the absent-main lifecycle; required
+exhaustion reports a missing-source diagnostic. No candidate-attempt history is
+added to public metadata.
+
+This keeps convention choice with applications while moving repeated selection
+and loading plumbing into the library's established lifecycle. It preserves
+explicit control, ordinary source behavior, and complete-on-return ownership.
+
+## Alternatives Considered
+
+- **Keep all search and fallback loading in each application.** This preserves
+  consumer ownership but repeats the file-selection and load coordination that
+  ConfigKit already owns, and risks divergent handling of selected-file errors.
+- **Search conventional locations implicitly during every load.** This reduces
+  setup, but activates filesystem access and precedence the consumer did not
+  select and makes ordinary source behavior less predictable.
+- **Return candidate paths for the application to load one by one.** This keeps
+  selection outside the load lifecycle and encourages repeated complete loads,
+  potentially rerunning defaults, callbacks, and validation during fallback.
+
+## Consequences
+
+The public search description must be immutable and root-owned, with private
+engine conversion and selection. The contract documents candidate ordering,
+selection, exhaustion, context, and provenance; the API declaration documents
+the public symbols. Dynamic bases and file availability are observed when each
+load consumes the description. Applications remain responsible for selecting
+conventions and for their schema and domain requirements.
+
+The [configuration contract](../config.md) owns implemented behavior, and the
+[component overview](../internal/overview.md) describes implementation ownership.
+The completed implementation plan and remediation record are preserved in Git
+history at `0369111` under `docs/roadmap/`.

docs/consumers/README.md

@@ -7,7 +7,7 @@ validation, schema-version policy, CLI parsing, runtime matching and conversion,
 resource checks, remote acquisition, and service initialization.
 
 The maintained [`examples/consumers`](../../examples/consumers) package demonstrates
-four sanitized shapes using only ConfigKit and the Go standard library:
+sanitized shapes using only ConfigKit and the Go standard library:
 
 | Shape | Demonstrated fit | Application code deliberately retained |
 | --- | --- | --- |
@@ -15,6 +15,13 @@ four sanitized shapes using only ConfigKit and the Go standard library:
 | Notarius-like | Canonical object bindings, a string-backed schema version accepting string or integer YAML, strict dynamic options, and `int64` dynamic integers | Catalog selection, allowed option keys, range-checked conversion to runtime `int` |
 | WeatherReporter-like | Defaults-only loading, report maps, canonical module objects, typed option unions, explicit CLI records, and typed secret startup | Report/module compatibility, rejection of explicitly empty domain lists, CLI parsing, and startup ordering |
 | Seriatim-like | Independent strict ordered speaker and autocorrect rule files | First-match and ordered replacement algorithms; no central application configuration file |
+| Bundled file | Simple native `fs.FS` source through ordinary `Load` | Selection and lifetime of the application-owned embedded filesystem |
+| Layered catalog | Embedded defaults with an import, a mapping underlay, an independent host main file, explicit false/zero input, and source-relative resource access | Domain validation and opening/interpreting the template resource |
+| Mounted collections | Entry-declared relative destinations, nested metadata/prompt/profile imports, local inheritance, and a version-only higher-tier override | Collection IDs, profile meaning, and opening/interpreting prompt resources |
+| Named presets | One-load sibling inheritance, explicit false, nested destination resolution, and source/derivation inspection | Choosing and executing a preset |
+| Effective configuration diff | Same-type frozen effective comparisons for two selected files or base-versus-overlay impact | Source/options selection and consumer-owned safe presentation |
+| Shared source-version checks | One `Definition.Version` policy for accepted declarations across participating source documents, with optional or required declarations and sanitized evidence | Choosing which declarations the application accepts; final assembled schema and domain validation |
+| Sequence catalogs | Declared collection operations, record inheritance, typed CLI and resolution, inspection, exact and wildcard application registrations | Catalog meaning and final domain validation |
 
 The YAML under [`testdata`](../../examples/consumers/testdata) is loaded by the
 executable examples and ordinary tests. It contains no private application data,
@@ -48,6 +55,180 @@ both without redefining their syntax. ConfigKit overlays are configuration overl
 they do not select or replace an application's LLM, model, pipeline, report, or
 execution profile concepts.
 
+## Explicit main-file discovery
+
+Applications choose the search conventions and their precedence, then pass the
+resulting `SearchConfig` source to the same `Load` or `LoadLayered` entry point.
+For example, the maintained sequence catalog puts a caller-selected file before
+a custom directory fallback while keeping its underlay and overlay choices
+independent. See [`sequence_catalog.go`](../../examples/consumers/sequence_catalog.go)
+and its [behavior tests](../../examples/consumers/sequence_catalog_test.go), plus
+the [working-directory executable example](../../examples/consumers/discovery_test.go).
+Together, the root-owned [discovery API](../../discovery.go) and [configuration
+discovery contract](../config.md#configuration-discovery) define ordered
+concatenation, directory-first Cartesian expansion, optional exhaustion, and
+selected-file behavior. [ADR 0019](../adr/0019-explicit-configuration-discovery.md)
+records why discovery is explicitly selected.
+
+## Import defaults and selection inspection
+
+`Options.ImportDefaults` and `LayeredOptions.ImportDefaults` apply one
+load-wide policy to enabled main, underlay, and transitive imports. Each field
+is resolved independently: a declaration's explicit value wins, then the
+application default, then the library default. `Required`, `Follow`, `Hidden`,
+and `Recursive` use nil pointers for unspecified values. `Pattern` applies to
+directory searches: nil leaves filenames unrestricted, while a non-nil empty
+slice selects no files. A declaration's own `pattern` replaces the application
+default. The defaults do not enable imports or change selected-overlay behavior.
+
+`Result.Sources`, `LoadError.Sources`, and `Resolution.Source` expose each
+declaring source's `ImportSelections`. These records identify the source-local
+declaration path, its authored location and selector, and the `none` outcome;
+they do not include candidate names or a guessed reason for absence. Returned
+records are detached snapshots. The [configuration contract](../config.md#explicit-imports)
+owns selector applicability and exact absence semantics.
+
+## Shared source-version checks
+
+[`LoadVersionedService`](../../examples/consumers/source_version.go) demonstrates
+if-present and required modes with one `Definition.Version` rule across a mounted
+main input and an underlay. The example reads only sanitized
+`SourceInfo.VersionCheck` fields; its executable test is in
+[`layered_test.go`](../../examples/consumers/layered_test.go). The
+[configuration contract](../config.md#shared-source-version-checks) defines
+participation, source-local lookup and diagnostics, non-main header consumption,
+main-path protection, default behavior, and evidence disclosure. Accepted
+declarations do not replace final assembled decoding or application validation.
+
+## Effective configuration diffs
+
+[`CompareFiles`](../../examples/consumers/diff.go) loads two caller-selected files
+with one application definition, handles each load error, calls `configkit.Diff`,
+and presents the safe records through consumer-owned `FormatDifferences`.
+[`CompareRolloutOverlay`](../../examples/consumers/diff.go) loads the same base
+once without an overlay and once with the selected overlay, so omitted lower
+priority values remain present. Its resolver records a derived endpoint URL after
+overlay application, and its nested typed secret reference is classified before
+the resulting records are presented.
+
+The maintained [behavior tests and executable examples](../../examples/consumers/diff_test.go)
+use temporary files and disposable secret values. Presenters should use
+`ValueSnapshot.Present` for absence, record membership for change, and
+`HiddenChanged` for a withheld change indicator. Do not parse the redaction marker
+or add separately rendered full contexts that lack combined sensitivity. The
+[configuration contract](../config.md#effective-configuration-diffs) owns shared
+equality, granularity, and disclosure semantics.
+
+## Named sibling inheritance
+
+[`LoadPresets`](../../examples/consumers/inheritance.go) loads the maintained
+[`presets.yml`](../../examples/consumers/testdata/inheritance/presets.yml) in one
+call. `custom` inherits `enabled: false` from `base`, while its nested
+`settings.primary` changes the inherited `settings.secondary` result at the
+custom destination. The application struct has no `extends` field; ConfigKit
+consumes the relationship before strict typed decoding.
+
+The [executable example](../../examples/consumers/consumers_test.go) reads
+`Metadata.IsExplicit` for the inherited false value, then follows
+`Origin.Inheritance` back to the parent path while `Origin.Locations` identifies
+the declaring source. Applications still choose which preset to execute and
+validate domain meaning. The [configuration contract](../config.md#sibling-inheritance)
+owns exact lookup, precedence, cancellation, and migration rules.
+
+## Native filesystem and layered input
+
+[`LoadBundled`](../../examples/consumers/layered.go) keeps the simple `Load` shape:
+it selects a file in an application-owned embedded filesystem and needs no
+underlay setup. [`LoadCatalog`](../../examples/consumers/layered.go) uses
+`LoadLayered` with an imported embedded-defaults group, a separate
+`Mapping` group, and a host main file supplied by its caller. The groups
+compose strictly within themselves and recursively across precedence boundaries;
+the main file's explicit `false` and `0` replace lower values without being
+mistaken for omissions. Its validator owns allowed modes and resource-name policy.
+
+[`ReadWelcome`](../../examples/consumers/layered.go) follows the effective field's
+origin location to a source ID, queries `Result.SourceContext`, and opens the
+resource relative to that context's `BaseDir`. It does not assume the main file
+owns a retained underlay value. A composite origin needs an application choice;
+ConfigKit does not guess a directory. The context query is passive, while later
+resource reads observe the caller-owned filesystem or a freshly opened host root
+and may fail independently of the completed configuration load. The
+[configuration contract](../config.md#source-resource-contexts) owns exact
+lifetime and precedence rules.
+
+[`LoadPromptBundle`](../../examples/consumers/layered.go) is the ordinary-root
+counterpart: its entry opts into imports through `Load`, imports metadata at the
+root, and places a prompt beneath `prompts` using YAML. The executable example
+and behavior test are in
+[`layered_test.go`](../../examples/consumers/layered_test.go).
+
+## Input destinations and mounted collections
+
+Main and underlay inputs use the same destination field. An import without a
+`destination` inherits its declaring document's effective destination; an
+explicit sequence of key strings appends a relative suffix. Nested imports
+append to their immediate parent's effective destination, while filesystem
+paths remain relative to the declaring file. Destinations are application
+mapping paths, independent of filesystem context. The configuration contract
+owns the complete behavior and validation rules.
+
+The small [`Example_inputDestination`](../../examples/consumers/destinations_test.go)
+mounts one mapping source beneath literal collection/prompt keys and loads a
+second input without a destination to show that root placement remains the
+default. Consumers pass paths, not filenames or namespace strings for ConfigKit
+to interpret.
+
+[`LoadCollectionBundle`](../../examples/consumers/destinations.go) assembles an
+embedded collection manifest mounted beneath a literal collection path. The
+entry's YAML places nested metadata imports at the collection root and prompt
+and profile peers beneath their own keys. A higher-priority input changes only
+one prompt's ordinary `version` field. The main document alone supplies the
+application schema version. A prompt's local `extends` relationship resolves
+after all tiers, so `custom` inherits the final `brief` content and fields while
+retaining its own profile selection.
+
+The resolver follows each effective `content_file` origin to its declaring
+source context. This also works for `custom`'s inherited resource. The
+application-owned [`ReadCollectionPromptContent`](../../examples/consumers/destinations.go)
+demonstrates the same lookup after loading; ConfigKit does not open or interpret
+the resource. [`destinations_test.go`](../../examples/consumers/destinations_test.go)
+checks source destinations and authored coordinates, presence, inherited values,
+relative resources, and strict peer conflicts. The
+[configuration contract](../config.md#input-destinations) owns shared placement,
+import, source-location, and ownership behavior.
+
+## Identified prompt sequences
+
+[`LoadPromptCatalog`](../../examples/consumers/prompt_catalog.go) shows the
+smaller import-focused adoption path: a registered `prompts.id` identity,
+directory and glob selection, a helper import that supplies an item's ID, and
+resource lookup through the effective source context. Its executable examples
+and tests are in
+[`prompt_catalog_test.go`](../../examples/consumers/prompt_catalog_test.go), with
+complete [catalog](../../examples/consumers/testdata/prompt-catalog/config.yml)
+and [required-file](../../examples/consumers/testdata/prompt-catalog/simple.yml)
+fixtures.
+
+[`LoadSequenceCatalog`](../../examples/consumers/sequence_catalog.go) integrates
+an underlay declaration, imported main fragments, identified-record inheritance,
+selected overlay `append`, `upsert`, and `replace`, a typed CLI override, and
+recorded application resolution. Its tests and runnable example demonstrate
+stable output order, whole-record upsert, provenance/history inspection,
+resource lookup for inherited records, and secret-safe explanation in
+[`sequence_catalog_test.go`](../../examples/consumers/sequence_catalog_test.go).
+[`LoadNamespacedMapCatalog`](../../examples/consumers/sequence_catalog.go) adds
+an exact root registration and a wildcard namespace registration, showing that
+each concrete sequence has an independent identity scope. The same tests show
+that a YAML identity declaration without an application registration does not
+create final-result identity enforcement.
+
+The examples keep prompt meaning and domain checks in the consuming application.
+The [configuration contract](../config.md#strict-document-composition) owns
+declaration, identity, operation, ownership, and final-validation semantics;
+[sibling inheritance](../config.md#sibling-inheritance) defines record
+relationships, and the [CLI contract](../config.md#explicit-cli-overrides) owns
+override ordering.
+
 Known module catalogs should use canonical object entries with a module identifier
 and typed options. A small union struct is sufficient when the available option
 fields are known; validation selects which fields apply to each module. Runtime-
@@ -126,6 +307,10 @@ focused behavioral owner:
 | Source/import/selected-overlay pipeline rules and artifact defaults | Narratio-shaped executable example and fixture |
 | Canonical module objects and dynamic option handling | WeatherReporter- and Notarius-shaped examples and migration tests |
 | `LoadSecretsDir`, bootstrap reporting, typed lookup, CLI explanation | `Example_weatherStartup` |
+| Native filesystem, grouped underlays, programmatic mapping, retained resource context | `Example_nativeFilesystem`, `Example_layeredCatalog`, and their focused consumer tests |
+| Literal input destinations, root-default compatibility, and mounted peer collections | `Example_inputDestination`, `LoadCollectionBundle`, and `destinations_test.go` |
+| Named sibling inheritance, presence, and derivation | `Example_inheritedPresets` and `TestPresetCatalogOneLoadAndDerivation` |
+| Effective configuration diffs and consumer-owned presentation | `ExampleDiff`, `ExampleCompareFiles`, and `ExampleCompareRolloutOverlay` |
 | Results, metadata, diagnostics, effective output, and writer failures | Focused root-package load, provenance, rendering, and explanation tests |
 
 The package-level import-boundary test covers the consumer examples too: supported

docs/development.md

@@ -8,32 +8,62 @@ public behavior.
 ## Initial orientation
 
 1. Inspect the working tree and preserve unrelated changes.
-   Agents must read and follow the [agent policy](policy/agents.md) before
-   recommending, planning, or implementing changes.
-2. Read the architecture policy for code or design work.
-3. Read the policy, contract, and internal documents applicable to the task.
+2. Use the Policy Reading Guide below to select applicable policies.
+3. Read the contract and internal documents applicable to the task.
 4. Inspect the relevant implementation and behavioral tests before changing them.
 
+## Policy Reading Guide
+
+| Policy | Read before… |
+| --- | --- |
+| [Policy set provenance](policy/meta.md) | Adopting policies, checking upstream revisions, or updating the adopted policy set. |
+| [Agents](policy/agents.md) | Recommending, planning, or implementing repository changes. |
+| [Architecture](policy/architecture.md) | Planning or changing Go library code or its structure. |
+| [Testing](policy/testing.md) | Selecting validation for code changes, or adding, changing, removing, or evaluating tests. |
+| [Documentation](policy/documentation.md) | Writing, revising, or reorganizing documentation. |
+| [OSS](policy/oss.md) | Adding or updating dependencies or incorporated third-party material, or changing licensing or attribution. |
+| [Release](policy/release.md) | Preparing or publishing a release, changing release procedures, or making versioning and compatibility decisions. |
+
+- Read applicable policies before making decisions they govern; multiple policies
+  may apply.
+- Select policies using the task triggers above. Follow cross-references to
+  relevant sections when needed to resolve a concrete question.
+- Reuse policies already available in context; reread when changed or no longer
+  available.
+- Expand reading when the task's scope expands.
+- When revising a policy itself, read that policy and any provisions elsewhere
+  affected by the revision.
+
 ## Task-specific reading guide
 
 | Task | Read |
 | --- | --- |
-| Repository orientation or component responsibility | [Architecture policy](policy/architecture.md) and [component overview](internal/overview.md) |
-| Documentation changes | [Documentation policy](policy/documentation.md) and the owning document |
-| Licensing, dependencies, attribution, or release-document changes | [OSS policy](policy/oss.md), [project grant](../COPYRIGHT), and [attribution](oss/attribution.md); release changes also follow the release policy and procedure |
-| Architecture decisions or future work | [Documentation policy](policy/documentation.md), [deferred scope](roadmap/deferred.md), and relevant ADRs listed below |
-| Code and test changes | [Architecture policy](policy/architecture.md), [testing policy](policy/testing.md), and the owning contract and tests from the map below |
+| Repository orientation or component responsibility | [Component overview](internal/overview.md) |
+| Input destinations | [Configuration contract](config.md#input-destinations), [ADR 0011](adr/0011-input-destinations.md), and the destination tests below |
+| Shared source-version checks | [Configuration contract](config.md#shared-source-version-checks), [ADR 0013](adr/0013-shared-source-version-checks.md), and the version/source-version tests below |
+| Documentation changes | The owning document |
+| Licensing, dependencies, attribution, or release-document changes | [Project grant](../COPYRIGHT) and [attribution](oss/attribution.md); release changes also follow the release procedure |
+| Architecture decisions or future work | [Future features](roadmap/future.md) and relevant ADRs listed below |
+| Code and test changes | The owning contract and tests from the map below |
 | Examples or copyable assets | The owning implemented contract and [consumer adoption guide](consumers/README.md) |
-| Release preparation | [Release policy](policy/release.md) and [release procedure](release.md) |
+| Release preparation | [Release procedure](release.md) |
 
 Accepted decisions:
 
 - [Separate composition and overlay](adr/0001-separate-composition-and-overlay.md)
+- [Check source versions with one shared policy](adr/0013-shared-source-version-checks.md)
 - [Own YAML semantics behind a private parser boundary](adr/0002-own-yaml-semantics.md)
 - [Preserve presence and record application resolution](adr/0003-preserve-presence-and-resolution-history.md)
 - [Secret references and explicit bootstrap](adr/0004-secret-references-and-explicit-bootstrap.md)
 - [Explicit overrides and safe explanation](adr/0005-explicit-overrides-and-safe-explanation.md)
 - [Keep the public facade root-owned](adr/0006-public-facade.md)
+- [Compare frozen effective configuration snapshots](adr/0010-effective-configuration-diff.md)
+- [Place inputs at literal application mapping paths](adr/0011-input-destinations.md)
+- [Share dependency-ready ordering](adr/0015-shared-dependency-ready-ordering.md)
+- [Separate import selection controls](adr/0016-independent-import-controls.md)
+- [Define identity and merge rules for each collection](adr/0017-collection-sequence-policy.md)
+- [Apply CLI overrides after inheritance and decoding](adr/0018-cli-after-structural-resolution.md)
+- [Keep main-file discovery explicit and composable](adr/0019-explicit-configuration-discovery.md)
 
 For cross-cutting changes, follow every applicable row. Completed implementation
 and remediation plans are preserved in Git history at `cb5b435`; use current
@@ -44,7 +74,9 @@ git show cb5b435:docs/roadmap/remediation.md
 ```
 
 Release-candidate, publication, and verification work follows the operational
-[release procedure](release.md).
+[release procedure](release.md). Its module-selected ReleaseKit `publish`
+invocation validates the committed candidate and publishes only the intended
+tag; those release checks remain distinct from the everyday development check.
 
 The completed string-and-integer schema-version implementation and remediation
 records are preserved in Git history at `244104f`. The
@@ -59,14 +91,109 @@ and current facade ownership belongs to the [component overview](internal/overvi
 
 ## Baseline validation
 
+The completed filesystem-source and underlay roadmap, original feature request,
+implementation plan, and resolved remediation record are preserved in Git history
+at `b604aa1` under `docs/roadmap/`. Current behavior belongs to the
+[configuration contract](config.md#layered-loading). Built-in sibling
+inheritance is now part of the [configuration contract](config.md#sibling-inheritance).
+The completed request, roadmap, plan, and resolved review findings are preserved
+in Git history at `83c59ea` under `docs/roadmap/`.
+
 The completed overlay rename plan and release-workflow simplification record are
 preserved in Git history at `73ce6e9` under `docs/roadmap/`. Current overlay
 behavior belongs to the [configuration contract](config.md#selected-overlays),
 and release operations belong to the [release procedure](release.md).
 
-Install Go 1.25.0 or a supported patched/newer Go toolchain. Acquire declared
-dependencies explicitly before entering an offline development or validation
-environment:
+The completed ReleaseKit adoption, startup performance request and experiments,
+benchmark evidence, performance audit, implementation plan, and remediation
+record are preserved in Git history at `8e91a2b` under `docs/roadmap/`. For example:
+
+```sh
+git show 8e91a2b:docs/roadmap/startup-benchmark.md
+```
+
+Remaining optimization candidates belong to
+[future performance experiments](roadmap/future.md#3-performance-experiments).
+
+The completed effective-configuration diff roadmap, implementation plan, and
+resolved review findings are preserved in Git history at `1c2610c` under
+`docs/roadmap/`. The
+[configuration contract](config.md#effective-configuration-diffs) owns current
+comparison and disclosure behavior, and
+[ADR 0010](adr/0010-effective-configuration-diff.md) records the decision.
+
+The completed input-destination, relative-import-destination, and shared
+source-version roadmaps, associated consumer request, implementation plan, and
+resolved review findings are preserved in Git history at `e4270c9` under
+`docs/roadmap/`. For example:
+
+```sh
+git show e4270c9:docs/roadmap/implementation.md
+git show e4270c9:docs/roadmap/remediation.md
+```
+
+Current behavior belongs to the configuration contract's
+[input destinations](config.md#input-destinations),
+[imports](config.md#explicit-imports), and
+[shared source-version checks](config.md#shared-source-version-checks) sections.
+Explicit sequence-item placement, collection operations, identity registration,
+and final registered-identity validation are owned by the
+[strict composition](config.md#strict-document-composition) section;
+[imports](config.md#explicit-imports) owns acquisition and scheduling. The
+[maintained sequence catalog](consumers/README.md#identified-prompt-sequences)
+shows the consumer boundary, and [ADR 0017](adr/0017-collection-sequence-policy.md)
+records the collection decision.
+
+The completed sequence-composition roadmap, implementation plan, and resolved
+remediation record are preserved in Git history at `008d2ba` under
+`docs/roadmap/`. For example:
+
+```sh
+git show 008d2ba:docs/roadmap/sequence-composition.md
+git show 008d2ba:docs/roadmap/implementation.md
+git show 008d2ba:docs/roadmap/remediation.md
+```
+
+The completed import-discovery roadmap, implementation plan, and resolved
+remediation record are preserved in Git history at `5747ec4` under
+`docs/roadmap/`. For example:
+
+```sh
+git show 5747ec4:docs/roadmap/imports.md
+git show 5747ec4:docs/roadmap/implementation.md
+git show 5747ec4:docs/roadmap/remediation.md
+```
+
+The subsequent import-integration audit and completed remediation record are
+preserved at `6903c9e:docs/roadmap/remediation.md`; retrieve them with
+`git show 6903c9e:docs/roadmap/remediation.md`.
+
+The completed sequence-identity/collection-policy roadmap and implementation
+plan are preserved in Git history at `d0a605a`:
+
+```sh
+git show d0a605a:docs/roadmap/sequences.md
+git show d0a605a:docs/roadmap/implementation.md
+```
+
+Current behavior belongs to the configuration contract's
+[strict composition](config.md#strict-document-composition),
+[sibling inheritance](config.md#sibling-inheritance), and
+[CLI overrides](config.md#explicit-cli-overrides) sections.
+The completed remediation record, including the algorithm-audit findings, is
+preserved at `ea46001:docs/roadmap/remediation.md`.
+
+The completed configuration-discovery roadmap, implementation plan, and
+remediation record are preserved in Git history at `0369111`, for example
+`git show 0369111:docs/roadmap/remediation.md`. Current behavior belongs to
+[configuration discovery](config.md#configuration-discovery); the public
+[discovery declarations](../discovery.go) own the Go API.
+
+Potential enhancements are tracked in [future features](roadmap/future.md).
+
+Install the Go version required by `go.mod` or a compatible newer toolchain.
+Acquire declared dependencies explicitly before entering an offline
+development or validation environment:
 
 ```sh
 go mod download
@@ -96,10 +223,10 @@ Use focused checks while iterating, with validation proportionate to the change
 under the testing policy. Documentation-only work normally needs the local-link
 check below and whitespace review; behavior-bearing examples and commands also
 need execution. Use `go test -race ./...` for ownership or concurrency changes.
-The [release checker](release.md#4-validate-the-source-candidate) performs one
-minimum-toolchain race-suite run, vet, module hygiene, and Linux cross-builds.
-It already covers examples, links, and package boundaries; do not additionally
-run the everyday checker just to repeat those checks. CI never gates a release.
+The [release procedure](release.md#4-publish-the-committed-candidate) performs
+its selected validation through one `publish` invocation. The everyday checker
+remains a development gate and is not a separate release prerequisite. CI never
+gates a release.
 
 ## Task-to-test map
 
@@ -110,15 +237,29 @@ code changes. Use the component overview to find the corresponding implementatio
 | Task | Behavioral test owners | Focused command |
 | --- | --- | --- |
 | YAML syntax, diagnostics, parser limits | [Adapter tests](../internal/yaml/parse_test.go), [source translation](../internal/engine/parse_test.go) | `go test ./internal/yaml` and `go test ./internal/engine -run '^TestParseSource'` |
-| File/reader access, imports, globs, containment | [Sources](../internal/engine/source_test.go), [FIFO](../internal/engine/source_fifo_test.go), [imports](../internal/engine/imports_test.go), [globs](../internal/engine/glob_test.go) | `go test ./internal/engine -run 'Source\|Import\|Glob\|Filesystem\|Nonregular\|RegularFile'` |
+| File/reader access, imports, globs, containment | [Sources](../internal/engine/source_test.go), [FIFO](../internal/engine/source_fifo_test.go), [imports](../internal/engine/imports_test.go), [relative destinations](../internal/engine/destination_import_test.go), [globs](../internal/engine/glob_test.go) | `go test ./internal/engine -run 'Source\|Import\|Glob\|Filesystem\|Nonregular\|RegularFile'` |
+| Explicit main-file discovery and absent-input loading | [Candidate selection](../internal/engine/discovery_test.go), [load integration](../internal/engine/discovery_load_test.go), [public facade](../facade_discovery_test.go), and maintained [catalog](../examples/consumers/sequence_catalog_test.go) and [preset](../examples/consumers/discovery_test.go) examples | `go test ./internal/engine -run 'Discovery|Search'`, `go test . -run 'Search'`, and `go test ./examples/consumers -run 'WorkingDirectoryPreset|SequenceCatalog'` |
+| Import defaults, empty-selection evidence, and dependency-ready ordering | [Defaults and facade evidence](../facade_import_defaults_test.go), [engine import evidence](../internal/engine/import_evidence_test.go), [scheduler](../internal/engine/dependency_order_test.go), [scheduling integrations](../internal/engine/imports_test.go) | `go test ./internal/engine -run 'Import|ScheduleDependencies|Inheritance'`, `go test . -run 'ImportDefaults|FacadeImport'`, and `go test ./examples/consumers` |
+| Native filesystem and mapping sources | [Native acquisition](../internal/engine/native_filesystem_test.go), [filesystem facade](../facade_filesystem_test.go), [mapping facade](../facade_mapping_test.go) | `go test ./internal/engine -run 'NativeFilesystem'` and `go test . -run 'TestFacade'` |
 | Composition, selected overlays, CLI precedence | [Composition](../internal/engine/compose_test.go), [overlay](../internal/engine/overlay_test.go), [selected overlays](../internal/engine/selected_overlay_test.go), [overrides](../internal/engine/override_test.go) | `go test ./internal/engine -run 'Compose\|Overlay\|Override'` |
+| Sequence identity, declarations, and operations | [Identity](../internal/engine/sequence_identity_test.go), [registrations](../internal/engine/sequence_registration_test.go), [declarations](../internal/engine/sequence_declaration_test.go), [combination](../internal/engine/sequence_combine_test.go), [final facade validation](../facade_final_sequence_identity_test.go), and [consumer catalog](../examples/consumers/sequence_catalog_test.go) | `go test ./internal/engine -run 'Sequence\|Collection'`, `go test . -run 'SequenceIdentity\|SequenceRegistration'`, and `go test ./examples/consumers` |
+| Sibling inheritance, provenance, history, sensitivity | [Expansion](../internal/engine/inheritance_test.go), [destination scopes](../internal/engine/inheritance_walk_test.go), [origins](../internal/engine/inheritance_origin_test.go), [history](../internal/engine/inheritance_history_test.go), [secrets](../internal/engine/inheritance_secret_test.go), [public loading](../facade_inheritance_test.go) | `go test ./internal/engine -run 'Inheritance\|Inherited'` and `go test . -run '^TestFacadeInheritance\|^TestFacadeInheritedSecrets'` |
+| Layered loading and source equivalence | [Grouped lifecycle](../internal/engine/load_request_test.go), [layered facade](../facade_layered_test.go), [equivalence](../facade_equivalence_test.go) | `go test ./internal/engine -run '^TestGrouped'`, `go test . -run '^TestFacadeLayered'`, and `go test . -run '^TestEquivalentSourceForms'` |
+| Input and relative-import destinations, mounted sources, and source ownership | [Destination engine tests](../internal/engine/destination_test.go), [tier tests](../internal/engine/destination_tiers_test.go), [import traversal and version tests](../internal/engine/destination_import_test.go), [accounting tests](../internal/engine/destination_accounting_test.go), [lifecycle inspection tests](../internal/engine/destination_import_lifecycle_test.go), [public source/error tests](../facade_destination_test.go), [resource contexts](../facade_resource_context_test.go), and [consumer examples](../examples/consumers/destinations_test.go) | `go test ./internal/engine -run 'Destination|Import|Glob|Mounted'`, `go test . -run 'Destination|Import|SourceContext|FacadeMounted'`, and `go test ./examples/consumers` |
+| Shared source-version modes and evidence | [Engine source-version tests](../internal/engine/source_version_test.go), [public facade tests](../facade_source_version_mode_test.go), and [consumer example tests](../examples/consumers/layered_test.go) | `go test ./internal/engine -run 'SourceVersion'`, `go test . -run 'SourceVersion'`, and `go test ./examples/consumers` |
 | Schema, defaults, projection, cloning | [Schema](../internal/engine/schema_test.go), [decoding](../internal/engine/decode_test.go), [projection](../internal/engine/projection_test.go) | `go test ./internal/engine -run 'Schema\|Decode\|Projection\|Clone\|Inline\|CompareDocument'` |
 | Lifecycle, resolution, validation, callback ownership | [Loading](../internal/engine/load_test.go), [resolution](../internal/engine/resolution_test.go), [validation](../internal/engine/validation_test.go), [ownership](../internal/engine/callback_ownership_test.go), [independence](../internal/engine/independence_test.go) | `go test ./internal/engine -run 'Load\|Resolution\|Validation\|Validator\|Hook\|Callback\|Parallel'` |
 | Paths, metadata, provenance | [Paths](../internal/engine/path_test.go), [metadata](../internal/engine/metadata_test.go), [provenance](../internal/engine/provenance_test.go) | `go test ./internal/engine -run 'Path\|Metadata\|Provenance\|Queries'` |
+| Passive resource contexts | [Engine contexts](../internal/engine/resource_context_test.go), [public contexts](../facade_resource_context_test.go) | `go test ./internal/engine -run 'Resource'` and `go test . -run 'SourceContext'` |
 | Secrets, bootstrap, redaction, explanation | [References](../internal/engine/secret_reference_test.go), [bootstrap](../internal/engine/secrets_test.go), [rendering](../internal/engine/render_test.go), [explanation](../internal/engine/explain_test.go) | `go test ./internal/engine -run 'Secret\|Bootstrap\|Effective\|Explain\|Explanation\|History\|Sensitivity'` |
-| Consumer examples and migration fixtures | [Consumer tests](../examples/consumers/consumers_test.go), [API examples](../example_test.go) | `go test ./examples/consumers` and `go test . -run '^Example'` |
+| Effective configuration diff | [Engine comparison and masking tests](../internal/engine/diff_test.go), [engine operation tests](../internal/engine/diff_operation_test.go), [root facade tests](../facade_diff_test.go), and [consumer examples](../examples/consumers/diff_test.go) | `go test ./internal/engine -run 'Diff|Explain|History|Secret|Independent'`, `go test . -run 'Diff|FacadeInspection|PublicFacadeBoundary|DependencyImportBoundary'`, `go test ./examples/consumers`, and `go test . -run '^ExampleDiff$'` |
+| Consumer examples and migration fixtures | [Consumer tests](../examples/consumers/consumers_test.go), [native, layered, and ordinary relative-import examples](../examples/consumers/layered_test.go), [mounted collection examples](../examples/consumers/destinations_test.go), [API examples](../example_test.go) | `go test ./examples/consumers` and `go test . -run '^Example'` |
+| Assembly and layered scaling evidence | [Assembly benchmarks](../internal/engine/assembly_bench_test.go), [layered benchmarks](../internal/engine/underlay_bench_test.go) | `go test ./internal/engine -run '^$' -bench '^BenchmarkUnderlay' -benchmem`; repeat with `^BenchmarkCompose` and `^BenchmarkOverlay` |
+| Identified-sequence scaling evidence | [Mixed-upsert benchmark](../internal/engine/sequence_combine_bench_test.go) | `go test ./internal/engine -run '^$' -bench '^BenchmarkSequenceMixedUpsert$' -benchmem` |
+| Inheritance scaling evidence | [Expansion benchmarks](../internal/engine/inheritance_bench_test.go) | `go test ./internal/engine -run '^$' -bench '^BenchmarkInheritance' -benchmem` |
 | Documentation links and dependency isolation | [Link checks](../documentation_test.go), [import boundary](../import_boundary_test.go), [public boundary](../public_boundary_test.go) | `go test . -run 'TestLocalDocumentationLinks\|TestDependencyImportBoundary\|TestPublicFacadeBoundary'` |
-| Check-command behavior | [Shell regression](../release_check_test.go) | `go test . -run '^TestCheckScripts'` |
+| Development check behavior | [Development checker test](../development_check_test.go) | `go test . -run '^TestDevelopmentCheckHandlesFilenamesAndStopsOnFailure$'` |
+| Release profile wiring | [Release profile test](../releasekit_profile_test.go) | `go test . -run '^TestReleaseKitProfile$'` |
 
 ## Fuzz validation
 

docs/internal/imports.md

@@ -0,0 +1,87 @@
+# Import Discovery and Scheduling Internals
+
+The [configuration contract](../config.md#explicit-imports) owns selector syntax,
+defaults, requiredness, placement, inspection evidence, and observable ordering.
+This note records implementation flow and private identities for maintainers.
+
+## Discovery and acquisition
+
+Each source's root directive is parsed into presence-aware declarations and
+resolved against load-wide defaults. Candidate selection preserves a normalized
+namespace path separately from canonical access identity: overlapping roots
+coalesce the same candidate spelling in that namespace, while aliases reached
+through distinct spellings retain separate inclusion routes for admission.
+Directory searches walk each distinct normalized root once, apply all filename
+patterns to discovered names, and form a set union of matching candidates across
+overlapping roots. Exclusions are applied as set difference after discovery and
+candidate normalization. They do not suppress discovery or resource errors.
+
+Directory traversal tracks canonical directories on the active traversal path.
+It adds an identity when descending and removes it when the frame is popped, so
+only a back-edge to an active directory is a traversal cycle; a later alias is
+not mistaken for one. This is separate from import dependency-cycle detection.
+For host sources, discovery uses rooted `Lstat` and canonical containment. Native
+sources use `fs.ReadLinkFS` inspection when supplied; otherwise traversal follows
+the capabilities and behavior of the provided `fs.FS`, without claiming a
+general sandbox guarantee.
+
+Acquisition remains authored: declarations are visited in source order and each
+selected candidate set in namespace-path lexical order. This preserves source
+records, IDs, source-local version checks, and callback ordering. The acquired
+inclusion graph is retained separately from composition scopes so cycles that
+cross item boundaries remain detectable. Source discovery does not itself choose
+sequence assembly order.
+
+## Stable keys and scheduling
+
+The shared scheduler compares immutable tuples component by component using Go's
+bytewise string order; if one tuple is a prefix of another, the shorter tuple
+sorts first. The import key is
+`(namespace-kind, namespace-anchor, resource-kind, resource-path)`:
+
+- Namespace kind is `host` or `native`. Host resource paths are canonical
+  absolute paths rendered with slash separators; native paths retain their
+  namespace-relative identity.
+- Anchors come from explicit input positions, not discovery order: main is
+  `(0,0)` and underlay/input positions are `(group+1,input+1)`, each encoded as
+  fixed-width decimal. Host accesses in one scheduled tier share its host anchor.
+  A native filesystem namespace uses its earliest explicit selecting position
+  in that tier. Filesystem tokens distinguish namespace equality, not sort order,
+  so separately constructed filesystems with the same label remain distinct.
+- Resource kind is `file` or `synthetic`. A synthetic root uses its explicit
+  input anchor and an empty resource path rather than a display label or token
+  address.
+
+Inheritance keys are
+`("definition", scope-pointer, definition-pointer)`, where both pointers use
+canonical escaped semantic path spelling. Source IDs are not part of the key.
+
+Both integrations use the same Kahn scheduler: it deduplicates dependency edges,
+keeps currently ready nodes in a min-heap, and selects the smallest ready key
+after every completion. Its scheduling cost is `O(E + V log V)` time and
+`O(V + E)` additional memory, excluding key construction, tuple copying, and
+tuple comparisons. On a stalled graph, deterministic DFS over the residual graph
+returns a closed cycle rotated to its smallest key; blocked dependents are not
+reported as cycle members.
+
+Import composition schedules a main tier or one underlay group as a single
+strict-scope graph. Applicable collection declarations are gathered for the
+scope before peer composition, including identity inherited from lower tiers.
+Identified peer sequences then combine distinct records in assembled source and
+list order; after the strict scope completes, layered assembly applies the
+resolved collection operation against the lower value, as defined by the
+[configuration contract](../config.md#strict-document-composition). Item
+contributions own nested local strict-mapping scopes; their helpers complete
+before the item is placed in its outer scope. Inheritance uses the same
+ready-node rule inside each sibling mapping scope, while preserving the authored
+mapping order in its output.
+These scopes do not flatten into one global graph, and independent precedence
+tiers remain separate.
+
+The main owners are [`import_selection.go`](../../internal/engine/import_selection.go),
+[`directory_walk.go`](../../internal/engine/directory_walk.go),
+[`import_graph.go`](../../internal/engine/import_graph.go),
+[`dependency_order.go`](../../internal/engine/dependency_order.go), and
+[`inheritance_schedule.go`](../../internal/engine/inheritance_schedule.go).
+Their focused behavior is covered by import-selection, scheduler, and scheduling
+integration tests under `internal/engine`.

docs/internal/overview.md

@@ -7,23 +7,47 @@ private state; public signatures and fields do not expose engine types.
 
 Implemented component owners:
 
-- `internal/engine` owns source acquisition, composition, schema inspection,
-  decoding, lifecycle coordination, callback auditing, provenance/history,
-  secret resolution and bootstrap, and safe inspection rendering. It never
-  imports the root package.
-- Root `Source`, `Path`, `Secret`, records, lifecycle callbacks, results, and
-  bootstrap reports are root-defined wrappers or records. Callback wrappers pass
-  only live engine context during a callback; `Result.Config` is detached and its
-  private inspection remains frozen independently.
-- Root conversion files explicitly cross the path, record, callback, secret, and
-  error boundaries. There are no public aliases, anonymous engine embeddings, or
-  public engine bridge methods.
+- `internal/engine` owns host and native-filesystem source acquisition and
+  explicitly selected configuration discovery. A search resolves once during
+  shared acquisition; the selected concrete file or absent-input state then
+  follows the existing composition, metadata, and resource-context lifecycle.
+  It also owns grouped strict composition, recursive precedence assembly,
+  per-input mapping and sequence-item placement, YAML collection declarations
+  and operations for identified sequences, and application identity registrations for strict
+  composition, inheritance, and final validation. It applies the selected
+  collection operation at precedence boundaries and owns dependency-ready,
+  destination-local inheritance before typed decoding. CLI assignment follows
+  inheritance and decoding, before application resolution. The engine also owns
+  shared source-version checking with sanitized declaration evidence.
+  Explicit import discovery supports declared paths, directory searches, and
+  globs; load-wide defaults and source-local empty-selection evidence cross the
+  root facade without changing acquisition order. Import and inheritance
+  resolution share dependency-ready scheduling within their composition scopes.
+  It retains each source's effective placement alongside physical source
+  identity and owns schema
+  inspection, lifecycle coordination, callback auditing,
+  provenance/history, passive source-context retention, secret resolution and
+  bootstrap, safe inspection rendering, and effective-value comparison over
+  frozen inspection snapshots. It never imports the root package.
+- Root `Source`, `Filesystem`, `Input`, `Underlay`, `Path`, `Secret`, records,
+  lifecycle callbacks, results, and bootstrap reports are root-defined wrappers
+  or records. Callback wrappers pass only live engine context during a callback;
+  `Result.Config` is detached and its private inspection remains frozen
+  independently.
+- Root conversion files explicitly cross the path, record, callback, secret,
+  search-description, and error boundaries. There are no public aliases,
+  anonymous engine embeddings, or public engine bridge methods.
+- Root `Diff` and `Difference` provide the public comparison boundary and
+  convert detached engine records to root-owned paths and snapshots; consumer
+  examples own presentation of the safe changed regions.
 - `internal/document` owns the parser-independent ordered tree and cloning.
   `internal/yaml` is the sole upstream YAML adapter and parser/dumper boundary.
-- Engine mechanism tests own source, composition, decoding, callback, provenance,
-  secret, history, rendering, and bootstrap behavior. Root tests own public API
-  compatibility, facade integration, documentation links, and dependency/public
-  boundary checks. Consumer examples remain under `examples/consumers`.
+- Engine mechanism tests own source, composition, inheritance, decoding,
+  callback, provenance,
+  source-context, secret, history, rendering, and bootstrap behavior. Root tests
+  own public API compatibility, facade integration, documentation links, and
+  dependency/public boundary checks. Consumer examples remain under
+  `examples/consumers`.
 
 Dependency direction is root to engine to document/YAML support. The root may
 import only `internal/engine` among project internal production packages; engine
@@ -32,8 +56,34 @@ these constraints and rejects exported aliases, fields, or signatures involving
 internal types.
 
 The [configuration contract](../config.md) owns implemented YAML and lifecycle
-semantics. The [consumer adoption guide](../consumers/README.md) owns application
-guidance. The [architecture policy](../policy/architecture.md) owns contributor
-boundaries, and [ADR 0006](../adr/0006-public-facade.md) records the facade
+semantics, including
+[configuration discovery](../config.md#configuration-discovery),
+[input destinations](../config.md#input-destinations),
+[shared source-version checks](../config.md#shared-source-version-checks), and
+[effective configuration diffs](../config.md#effective-configuration-diffs).
+The [strict composition contract](../config.md#strict-document-composition)
+owns sequence declarations, identity, operations, ownership, and final
+validation; [CLI overrides](../config.md#explicit-cli-overrides) own override
+ordering. The [consumer guide](../consumers/README.md#identified-prompt-sequences)
+links maintained workflow examples.
+The [consumer adoption guide](../consumers/README.md) owns application guidance.
+The [architecture policy](../policy/architecture.md) owns contributor
+boundaries; [ADR 0006](../adr/0006-public-facade.md) records the facade decision
+and [ADR 0010](../adr/0010-effective-configuration-diff.md) records the diff
+decision; [ADR 0011](../adr/0011-input-destinations.md) records the placement
 decision. See the [development guide](../development.md) for validation commands
-and [release procedure](../release.md) for source-candidate gates.
+and [release procedure](../release.md) for source-candidate gates. [ADR
+0009](../adr/0009-sibling-inheritance.md) records why inheritance is a built-in
+post-assembly structural operation. [ADR 0012](../adr/0012-relative-import-destinations.md)
+records the relative-import extension; [ADR 0013](../adr/0013-shared-source-version-checks.md)
+records the source-version decision.
+[ADR 0014](../adr/0014-sequence-placement-and-composition.md) records explicit
+sequence placement and composition. [ADR 0015](../adr/0015-shared-dependency-ready-ordering.md)
+records the shared dependency-ready ordering decision; [ADR
+0016](../adr/0016-independent-import-controls.md) records the independent
+selection controls. [ADR 0017](../adr/0017-collection-sequence-policy.md) and
+[ADR 0018](../adr/0018-cli-after-structural-resolution.md) record collection
+operations and CLI ordering. [ADR 0019](../adr/0019-explicit-configuration-discovery.md)
+records explicit main-file discovery. The [import internals](imports.md)
+document candidate and namespace identities, discovery and scheduling, and the
+bounded algorithms.

docs/oss/attribution.md

@@ -1,11 +1,31 @@
-# Open Source Attribution
+# Open Source Attribution Notices
 
-Component notices follow the [OSS policy](../policy/oss.md). ConfigKit's own
-grant is in [COPYRIGHT](../../COPYRIGHT); dependency notices do not change it.
+## Standard Repository Policies
+
+Material: `docs/policy/release.md`, adapted from
+`e833faddf120c789a9b45348edaf75720de16348`; `docs/policy/meta.md`, `docs/policy/oss.md`,
+`docs/policy/documentation.md`, `docs/policy/agents.md`,
+`docs/policy/architecture.md`, `docs/policy/testing.md`; root `AGENTS.md`; and the
+Policy Reading Guide in `docs/development.md`, adapted from
+`d84a38ebab26f048cafbe59a2246700c35d29843` for this repository.
+
+Copyright (C) 2026 Eric Rakestraw
+
+SPDX-License-Identifier: CC-BY-SA-4.0
+
+License and notices: [CC BY-SA 4.0](licenses/CC-BY-SA-4.0.txt) |
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/COPYRIGHT) |
+[LICENSE](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/LICENSE) |
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/policy/src/commit/e833faddf120c789a9b45348edaf75720de16348/COPYRIGHT) |
+[LICENSE](https://gitea.maximumdirect.net/eric/policy/src/commit/e833faddf120c789a9b45348edaf75720de16348/LICENSE).
+
+[Source](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843).
+
+[Source](https://gitea.maximumdirect.net/eric/policy/src/commit/e833faddf120c789a9b45348edaf75720de16348).
 
 ## go-yaml v4
 
-Version: `go.yaml.in/yaml/v4 v4.0.0-rc.6`.
+Selected module: `go.yaml.in/yaml/v4` at `v4.0.0-rc.6`.
 
 Copyright 2011-2019 Canonical Ltd
 
@@ -17,12 +37,7 @@ SPDX-License-Identifier: Apache-2.0 AND MIT
 
 License and notices: [Apache 2.0](licenses/Apache-2.0.txt) |
 [MIT](licenses/MIT.txt) |
-[upstream NOTICE](https://github.com/yaml/go-yaml/blob/1c17b9cee72bf81ae73a8be50fbd7dd3a9985125/NOTICE) |
-[upstream LICENSE](https://github.com/yaml/go-yaml/blob/1c17b9cee72bf81ae73a8be50fbd7dd3a9985125/LICENSE)
+[NOTICE](https://github.com/yaml/go-yaml/blob/1c17b9cee72bf81ae73a8be50fbd7dd3a9985125/NOTICE) |
+[LICENSE](https://github.com/yaml/go-yaml/blob/1c17b9cee72bf81ae73a8be50fbd7dd3a9985125/LICENSE).
 
-Source: [go-yaml](https://github.com/yaml/go-yaml/tree/1c17b9cee72bf81ae73a8be50fbd7dd3a9985125).
-
-The upstream NOTICE identifies the libyaml-derived portion as MIT-licensed and
-the remaining project files as Apache-2.0-licensed; these are not alternative
-licenses for the entire module. The statements above preserve the NOTICE's
-wording. The module declares no additional Go module requirements.
+[Source](https://github.com/yaml/go-yaml/tree/1c17b9cee72bf81ae73a8be50fbd7dd3a9985125).

docs/oss/licenses/CC-BY-SA-4.0.txt

@@ -0,0 +1,170 @@
+Creative Commons Attribution-ShareAlike 4.0 International
+
+ Creative Commons Corporation (“Creative Commons”) is not a law firm and does not provide legal services or legal advice. Distribution of Creative Commons public licenses does not create a lawyer-client or other relationship. Creative Commons makes its licenses and related information available on an “as-is” basis. Creative Commons gives no warranties regarding its licenses, any material licensed under their terms and conditions, or any related information. Creative Commons disclaims all liability for damages resulting from their use to the fullest extent possible.
+
+Using Creative Commons Public Licenses
+
+Creative Commons public licenses provide a standard set of terms and conditions that creators and other rights holders may use to share original works of authorship and other material subject to copyright and certain other rights specified in the public license below. The following considerations are for informational purposes only, are not exhaustive, and do not form part of our licenses.
+
+Considerations for licensors: Our public licenses are intended for use by those authorized to give the public permission to use material in ways otherwise restricted by copyright and certain other rights. Our licenses are irrevocable. Licensors should read and understand the terms and conditions of the license they choose before applying it. Licensors should also secure all rights necessary before applying our licenses so that the public can reuse the material as expected. Licensors should clearly mark any material not subject to the license. This includes other CC-licensed material, or material used under an exception or limitation to copyright. More considerations for licensors.
+
+Considerations for the public: By using one of our public licenses, a licensor grants the public permission to use the licensed material under specified terms and conditions. If the licensor’s permission is not necessary for any reason–for example, because of any applicable exception or limitation to copyright–then that use is not regulated by the license. Our licenses grant only permissions under copyright and certain other rights that a licensor has authority to grant. Use of the licensed material may still be restricted for other reasons, including because others have copyright or other rights in the material. A licensor may make special requests, such as asking that all changes be marked or described.
+
+Although not required by our licenses, you are encouraged to respect those requests where reasonable. More considerations for the public.
+
+Creative Commons Attribution-ShareAlike 4.0 International Public License
+
+By exercising the Licensed Rights (defined below), You accept and agree to be bound by the terms and conditions of this Creative Commons Attribution-ShareAlike 4.0 International Public License ("Public License"). To the extent this Public License may be interpreted as a contract, You are granted the Licensed Rights in consideration of Your acceptance of these terms and conditions, and the Licensor grants You such rights in consideration of benefits the Licensor receives from making the Licensed Material available under these terms and conditions.
+
+Section 1 – Definitions.
+
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+
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+
+Section 2 – Scope.
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+     d.	Nothing in this Public License constitutes or may be interpreted as a limitation upon, or waiver of, any privileges and immunities that apply to the Licensor or You, including from the legal processes of any jurisdiction or authority.
+
+Creative Commons is not a party to its public licenses. Notwithstanding, Creative Commons may elect to apply one of its public licenses to material it publishes and in those instances will be considered the “Licensor.” Except for the limited purpose of indicating that material is shared under a Creative Commons public license or as otherwise permitted by the Creative Commons policies published at creativecommons.org/policies, Creative Commons does not authorize the use of the trademark “Creative Commons” or any other trademark or logo of Creative Commons without its prior written consent including, without limitation, in connection with any unauthorized modifications to any of its public licenses or any other arrangements, understandings, or agreements concerning use of licensed material. For the avoidance of doubt, this paragraph does not form part of the public licenses.
+
+Creative Commons may be contacted at creativecommons.org.

docs/policy/agents.md

@@ -1,12 +1,14 @@
 # Agent Policy
 
-**Base Policy Version:** 1.1
+**Base Policy Version:** 1.3
 
-**Last Updated**: 2026-09-23
+**Last Updated**: 2026-09-28
+
+**Upstream Source:** [Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/docs/policy/agents.md)
 
 ## Purpose
 
-Agents working in this repository must read and adhere to the following house rules.
+Agents must read and follow these rules.
 
 ## Implementation Discipline
 
@@ -14,8 +16,6 @@ Agents working in this repository must read and adhere to the following house ru
 request. Do not implicitly strengthen requirements, restrictions, or guarantees
 beyond what the user actually requested.
 
-Simplify the mechanism, not the user's choices.
-
 **Keep implementation machinery proportionate.** Use straightforward,
 idiomatic code and introduce only the machinery needed to support the requested
 behavior and flexibility. Optimize for conceptual simplicity and
@@ -57,15 +57,15 @@ the ambiguity rather than treating repetition as approval.
 
 ## Git Commit Policy
 
-By default, create a commit after completing each coherent unit of work, using a
+By default, commit each completed, nonempty unit of work using a
 concise, plain-English message describing what changed. This policy is standing
 authorization to create those local commits; a separate user request is not
 required. An explicit user instruction to leave work uncommitted takes precedence.
 
 A unit of work is a focused, reviewable outcome, including its relevant tests and
-documentation. Do not commit after every intermediate edit or create empty commits.
+documentation.
 Complete the appropriate validation before committing. If work is incomplete or
-validation is blocked, report that state rather than presenting it as completed.
+validation is blocked, report that state accurately.
 
 Before committing:
 
@@ -73,10 +73,10 @@ Before committing:
    changes. Identify changes that predate the current unit of work.
 2. Exclude secrets, local environment files, generated junk, and unrelated changes.
 3. Stage only the files or hunks belonging to the completed unit. Use `git add .`
-   only when every included change belongs to that unit. Do not disturb unrelated
-   staged or unstaged work.
-4. Review `git diff --staged` and run appropriate checks for the change. Do not
-   repeat checks already passed for unchanged content merely to create a commit.
+   only when every included change belongs to that unit. Preserve unrelated
+   staged and unstaged work.
+4. Review `git diff --staged` and run appropriate checks for the change. Reuse
+   successful checks for unchanged content.
 5. Review `git log --oneline -n 10` and use
    `git commit -m "<concise plain-English commit message>"`.
 6. Report the commit identifier and any remaining uncommitted work.

docs/policy/architecture.md

@@ -1,18 +1,61 @@
 # Architecture Policy
 
-**Base Policy Version:** 1.0
+**Base Policy Version:** 1.3
 
-**Last Updated:** 2026-09-06
+**Last Updated**: 2026-10-22
 
-## Purpose and applicability
+**Upstream Source:** [Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/docs/policy/architecture.md)
+
+## Purpose And Ownership
+
+The adopted policy defines the application's purpose and the architectural
+constraints contributors must follow. It owns system boundaries, responsibility
+and dependency rules, established invariants, and explicit non-goals.
+
+Describe the concrete package inventory and implementation mechanics in internal
+documentation. Link to canonical public contracts for their exact behavior and
+to ADRs for decision rationale.
 
 ConfigKit is an opinionated Go library for consistent YAML configuration loading
-and resolution across consuming applications. This policy governs contributions.
-The [component overview](../internal/overview.md) owns implementation inventory, the
-[configuration contract](../config.md) owns implemented behavior, and the
-[deferred scope](../roadmap/deferred.md) preserves deferred scope.
+and resolution across consuming applications. The [component overview](../internal/overview.md)
+owns implementation inventory, the [configuration contract](../config.md) owns
+implemented behavior, and the [future feature list](../roadmap/future.md) preserves
+candidates for future consideration.
 
-## Success criteria
+## Adopted Constraints And Implemented Structure
+
+Architectural constraints govern current and future development. Record
+implemented structure accurately, proposals and implementation status in the
+roadmap, and significant decisions and rationale in ADRs. Describe a target
+structure as implemented when its changes land.
+
+Constraints must reflect deliberately selected requirements and decisions.
+Do not promote incidental implementation choices into architectural invariants.
+
+The implemented collection-policy and CLI-ordering constraints below reflect
+accepted [ADR 0017](../adr/0017-collection-sequence-policy.md) and
+[ADR 0018](../adr/0018-cli-after-structural-resolution.md). The configuration
+contract owns their current behavior; these architectural constraints describe
+the system boundaries and guarantees that guide changes to that behavior.
+
+## Success Criteria
+
+ConfigKit prioritizes a coherent configuration model: consistency and
+predictability take precedence over flexibility for accommodating individual
+downstream conventions. Consumers should learn one set of rules, not different
+combination or presence semantics depending on the source format or consuming
+application. Distinct operations such as strict composition and intentional
+overlay express distinct purposes within that model.
+
+Consumers should be able to load once and receive a complete, validated
+configuration with inspectable provenance for its final values, including
+defaults and recorded application-derived values. Configuration and metadata
+together must distinguish explicit zero, false, empty, and null input from
+omission; ordinary Go values alone need not encode those distinctions.
+Application-owned resolution belongs within the recorded loading lifecycle, so
+consumers need no subsequent generic merging, defaulting, or provenance
+reconstruction. This does not transfer domain execution or runtime resource
+management into ConfigKit.
 
 1. **Reduce application infrastructure:** Can applications delete substantial
    configuration infrastructure while retaining clear ownership of their domain
@@ -21,8 +64,11 @@ The [component overview](../internal/overview.md) owns implementation inventory,
    configuration model, with only the flexibility needed to express genuine
    application requirements?
 
-Both criteria must hold. ConfigKit should not preserve divergent consumer
-conventions merely for compatibility, nor impose restrictions that prevent useful
+Both criteria must hold. Minimize consumer loading and processing code subject
+to the consistency, presence, and provenance principles above, rather than
+trading those principles for consumer-specific shortcuts. ConfigKit should not
+preserve divergent consumer conventions merely for compatibility, nor impose
+restrictions that prevent useful
 domain information from being expressed. Prefer a canonical representation using
 existing primitives before adding another mechanism. Extend the model when a
 concrete requirement cannot be accommodated cleanly, not simply because a
@@ -51,24 +97,128 @@ boundaries, and keep simple consumers independent of optional composition
 features. The [consumer adoption guide](../consumers/README.md) demonstrates the
 implemented surface against representative simple and complex shapes.
 
-## Responsibility boundaries
+## Simplicity, Defaults, And Explicit Controls
+
+These principles apply throughout ConfigKit: to configuration syntax, the public
+Go API, defaults, and feature design. Evaluate their effects on both configuration
+authors and consuming applications.
+
+**Keep straightforward workflows straightforward.** Common configuration
+workflows should require little configuration text and minimal API setup.
+Support more demanding workflows through explicit, composable options, without
+requiring simple consumers to understand or configure those options.
+
+**Prefer simple, permissive defaults with explicit controls.** Choose predictable
+defaults that minimize required setup and accommodate valid configurations
+without unnecessary restrictions. Provide selectable options for workflows that
+need additional capabilities, narrower behavior, or stronger requirements.
+
+Measure simplicity by what consumers must understand and maintain, including
+configuration text and application-side plumbing. Concise syntax is useful, but
+hidden inference and interacting meanings can make a shorter declaration harder
+to understand. Prefer explicitness where it makes behavior more predictable.
+A terse configuration format that requires substantial application-side
+infrastructure does not satisfy the simplicity principle.
+
+Define what permissiveness means for each behavior. Allowing an optional
+contribution to be absent or accepting valid inputs without an unnecessary
+filename restriction can reduce required setup. Invalid declarations, ambiguous
+composition, and unreadable selected sources must still produce meaningful
+errors under the applicable contracts. Permissiveness does not authorize silent
+recovery from invalid supplied configuration or weaken configuration integrity.
+
+Options should express coherent choices with understandable purposes and fit
+ConfigKit's shared configuration model. Support powerful controls when they
+serve concrete needs; these principles do not require a switch for every
+implementation behavior or conceivable consumer preference.
+
+Defaults require judgment when simplicity and permissiveness pull in different
+directions. Broader discovery can accommodate more layouts while increasing the
+implicit search scope. Evaluate such tradeoffs explicitly; these principles do
+not mechanically select the broadest behavior for every option. Changes to
+existing defaults remain subject to compatibility review, and proposed behavior
+remains in the roadmap until implemented.
+
+## Responsibility Boundaries
 
 ConfigKit owns configuration input processing and the coordination of decoding,
 resolution, validation, and inspection. Applications own their configuration
 types, field meanings, defaults, normalization, semantic validation, and schema
-version policy. Applications also own main-file search conventions, CLI wiring,
-remote acquisition, runtime initialization, and resource checks.
+version policy. Applications choose and order their main-file search conventions;
+ConfigKit provides explicitly selected search descriptions that resolve during
+loading. Applications also own CLI wiring, remote acquisition, runtime
+initialization, and resource checks. See the [configuration discovery
+contract](../config.md#configuration-discovery) and [ADR
+0019](../adr/0019-explicit-configuration-discovery.md).
+
+The engine applies each input's mapping destination within the existing source
+assembly, applies immediate-parent-relative YAML destinations to imports, and
+retains each effective placement with source identity and inspection records;
+the root facade owns the public fields and conversions. The
+[configuration contract](../config.md#input-destinations) defines the observable
+placement behavior. [ADR 0011](../adr/0011-input-destinations.md) records input
+placement, and [ADR 0012](../adr/0012-relative-import-destinations.md) records
+the import extension.
 
 Library code must not depend on consuming applications or initialize their
-runtime resources. It must not perform implicit network access, discover
-application-specific paths, or change process-global state during ordinary `Load`.
+runtime resources. It must not perform implicit network access, implicitly
+discover application-specific paths, or change process-global state during
+ordinary `Load`.
+Import discovery is available only through declarations in selected sources:
+explicit `path`, `dir`, and `glob` selectors may search their declared scope, but
+ConfigKit does not search conventional application paths unless the application
+explicitly supplies a discovery description, and it never discovers a main
+configuration file implicitly. Imports and sibling inheritance share
+dependency-ready scheduling within their existing scopes; acquisition order and
+precedence-tier boundaries remain distinct. The [configuration contract](../config.md#explicit-imports)
+owns observable behavior; [ADR 0015](../adr/0015-shared-dependency-ready-ordering.md)
+and [ADR 0016](../adr/0016-independent-import-controls.md) record the decisions.
 The explicit secrets-directory bootstrap is a narrow, opt-in exception: applications
 invoke it during startup, and it reports writes, skips and partial failures. It
 must never run implicitly as part of configuration loading.
 Remote data can enter through application-supplied input without introducing a
 network provider into the library.
 
-## Public API and dependency direction
+## Loading Lifecycle
+
+Configuration loading is a synchronous, complete-on-return operation. A successful
+load provides the final configuration and inspection metadata after the configured
+processing and validation phases complete. A failed load reports diagnostics and
+returns no usable partial result. The normal application pattern is one load near
+startup; applications may explicitly initiate additional loads.
+
+ConfigKit releases its library-owned loading handles before returning and remains
+inactive until the application explicitly invokes it again. It performs no
+background watching, refresh, or mutation of published results. Caller-owned
+resources and application callback effects remain the caller's responsibility.
+The [configuration contract](../config.md#completion-and-resource-lifetime) owns
+the precise completion and ownership behavior. The proposed decision record is
+[ADR 0008](../adr/0008-complete-on-return-loading.md).
+
+### Accepted Processing Order
+
+Complete source composition and precedence, including selected overlays, before
+sibling inheritance. Then apply typed defaults and decode the configuration.
+Apply explicit CLI overrides to that configuration and check their types before
+running application resolution. Effective secret lookup and final validation
+follow resolution, before publication. [ADR 0018](../adr/0018-cli-after-structural-resolution.md)
+records this ordering.
+
+CLI overrides are the highest-priority input to application resolution. Supplied
+sequences replace whole sequences, and mappings combine recursively. Inheritance
+and typed defaulting do not run again after CLI application. CLI paths and values
+must not introduce structural directives; earlier source, inheritance, and
+decoding failures remain errors even if a CLI assignment would replace the value.
+Semantic validation assesses the final configuration after overrides and resolution.
+
+Applications own flag parsing and domain resolution. ConfigKit owns override
+application, validation, and source attribution. Resolution receives CLI values
+with their explicit-presence and source information. Absence-based defaults
+preserve explicit values; recorded normalization and derivation can still change
+them. Typed defaults and application resolution retain their own assignment
+semantics, independently of collection operations during source assembly.
+
+## Public API And Dependency Direction
 
 Keep one small, coherent public surface for the supported lifecycle. Simple
 single-document consumers must not need import, overlay, or provider machinery.
@@ -94,25 +244,62 @@ Dependencies must preserve those boundaries; package splits and abstractions
 must earn their complexity. Do not impose a full application or hexagonal
 framework on this library.
 
-## Configuration integrity
+## Configuration Integrity
 
-Composition and intentional overlay are distinct operations. Composition must
-not silently become last-wins override through file ordering. The decision and
-alternatives are recorded in [ADR 0001](../adr/0001-separate-composition-and-overlay.md).
+Within a configuration tier, independent contributions use strict composition.
+Shared mappings combine recursively. Sequences with an applicable identity
+combine distinct records and reject duplicate identities, including equal
+records. Other overlapping non-mapping values remain conflicts, including equal
+values. Conflicting identity or operation declarations among peers also fail.
+Traversal order establishes stable reporting and record order; it does not grant
+precedence to peers. [ADR 0001](../adr/0001-separate-composition-and-overlay.md)
+records the distinction between strict composition and intentional overrides.
+
+The main document and its imports form a strictly composed tier. Explicit
+underlay groups compose strictly within each group, then combine from lowest to
+highest beneath the main tier. Between tiers, mappings combine recursively and
+retain omitted lower-priority children. Sequence values follow collection policy;
+other present values retain the established replacement rules. Source acquisition
+kind does not determine precedence. Input-specific constraints, including version
+ownership and path protections, remain part of the configuration contract.
+Consistent combination semantics do not require identical acquisition or lifetime
+behavior from every source kind.
+
+Built-in sibling `extends` relationships resolve after source precedence in the
+parser-independent document representation. Preserve existing mapping-sibling
+scopes and allow an identified sequence to provide a sibling scope for its
+records. A record may inherit from one parent in that sequence, selected by
+complete identity. The child supplies and keeps its own identity while inheriting
+the parent's other settings. Parents remain ordinary records subject to normal
+validation.
+
+Use the shared dependency ordering and preserve assembled sequence order.
+Resolve enclosing relationships before nested destination-local relationships.
+Mappings combine recursively; sequences use the inheriting collection's policy.
+Whole-record upsert replaces records during combination; explicit inheritance
+uses the records that remain. Inheritance remains built-in and creates no
+acquired source.
+[ADR 0009](../adr/0009-sibling-inheritance.md) records the
+original scope and continuing ownership decisions, with sequence combination
+and identified-sequence inheritance defined by
+[ADR 0017](../adr/0017-collection-sequence-policy.md) and CLI ordering by
+[ADR 0018](../adr/0018-cli-after-structural-resolution.md).
 
 ConfigKit must define supported YAML semantics explicitly rather than inherit
 parser defaults. Processing order and diagnostics must be deterministic for the
 same inputs and options. Invalid input must not produce a successful usable
 configuration. Do not run application hooks on invalid typed configuration.
 
-User-controlled precedence is application defaults, composed base, selected
-overlay, then explicitly supplied CLI overrides. Applications own flag parsing;
-ConfigKit owns overlay semantics and provenance. Domain resolution follows these
-inputs and must remain recorded, not become a hidden override channel.
+User-controlled precedence is application defaults, ordered underlays, composed
+main input, selected overlay, then explicitly supplied CLI overrides.
+This priority order is distinct from processing order: typed defaults are applied
+at decoding, and application resolution follows CLI input under the lifecycle
+rules above.
 
-Preserve node-based composition until the effective input is ready for typed
-decoding. Preserve presence and source information through processing. Ordinary Go zero
-values must not be used to infer whether input was absent. Final configuration,
+Preserve node-based composition through source assembly and inheritance until
+typed decoding. Preserve presence and source information through later CLI and
+application-resolution changes as well. Ordinary Go zero values must not be used
+to infer whether input was absent. Final configuration,
 metadata, and effective inspection must agree, including application resolution
 changes; see [ADR 0003](../adr/0003-preserve-presence-and-resolution-history.md).
 Safe historical values and an explanation renderer are part of the implemented contract,
@@ -122,7 +309,80 @@ See [ADR 0005](../adr/0005-explicit-overrides-and-safe-explanation.md).
 Detailed syntax and operation tables belong to the
 [current configuration contract](../config.md).
 
-## Ownership and confidentiality
+The frozen inspection boundary also supports comparing completed same-type
+results without reopening sources or rerunning the load lifecycle. The
+[configuration contract](../config.md#effective-configuration-diffs) owns
+comparison and disclosure behavior, the [component overview](../internal/overview.md)
+owns implementation responsibility, and [ADR 0010](../adr/0010-effective-configuration-diff.md)
+records the accepted decision.
+
+## Collection Identity And Combination
+
+ConfigKit owns a common collection policy for imported records, inline sequences,
+selected overlays, and sibling inheritance. Configuration authors may declare
+identity and combination rules; applications may register authoritative identity
+constraints. Configuration declarations must agree with application constraints.
+Keep source placement explicit and separate from policy, retaining the placement
+decision in [ADR 0014](../adr/0014-sequence-placement-and-composition.md).
+[ADR 0017](../adr/0017-collection-sequence-policy.md) owns the rationale for
+collection policy and its relationship to application authority.
+
+Gather declarations for the relevant destination and source or item-local scope
+before strict composition. Applicable identity from accumulated lower tiers must
+be available when composing higher-tier peers. Higher-tier declarations cannot
+repair invalid lower-tier composition. Preserve the distinction between source
+acquisition, dependency-ready scheduling within scopes, and precedence order.
+
+Strictly compose each tier's contributions before applying one operation for the
+collection against its lower value. Support whole-sequence replacement,
+duplicate-rejecting append, and whole-record replacement by identity (`upsert`).
+Append and upsert require identity; do not infer it from record fields or position.
+Duplicate identities among peers fail under every mode. Source precedence and
+inheritance use the same operations and deterministic ordering rules. Whole-record
+upsert replaces the matching record's fields together; recursive record merging
+and unkeyed sequence concatenation are outside this operation model.
+
+An explicit mode persists at its applicable destination until a higher explicit
+mode changes it. With no explicit mode, effective identity selects upsert and
+its absence selects whole-sequence replacement. Inferred defaults do not become
+persistent instructions. The inheriting destination chooses its operation; copying
+a parent collection does not automatically copy its mode to that destination.
+
+Track YAML identity and explicit modes according to their separate lifetimes.
+Actual whole-value replacement discards lower YAML identity while preserving
+application constraints and any new identity declaration. Item-local policies
+belong to their records: retaining a record retains its rules, and discarding it
+discards those rules. Policies independently applicable at a destination remain
+in effect. Inheritance can copy YAML identity subject to agreement and replacement
+rules; application registrations continue to constrain their registered paths.
+Numeric positions alone do not establish policy ownership.
+
+Allow declarations without accompanying records. A key declaration validates a
+retained sequence immediately or remains pending in its owning scope when no
+sequence exists. A mode-only declaration affects later combinations without
+recombining earlier tiers. Neither declaration alone clears a collection, and
+declaring replace alone does not authorize changing a retained collection's
+identity. These rules do not independently impose path-existence or shape
+requirements.
+
+Enforce YAML identity during source composition, precedence, and identified
+inheritance operations. Application registrations additionally constrain final
+effective sequences after defaults, CLI overrides, and application resolution.
+The application schema and validation own existence, nullability, and allowed
+shape. The final identity guarantee covers actual sequences on successful load;
+it does not cover every intermediate callback state or later caller mutations.
+YAML-only declarations carry no such final guarantee through defaults, CLI
+assignments, or application resolution.
+
+Preserve source attribution, presence, history, sensitivity, and resource context
+as records survive, move, or are replaced. Identity diagnostics use paths and
+available origin information without exposing identity values. The guarantee
+requires no new mutation-history system or exact reconstruction of causes for
+records supplied by defaults or callbacks. Exact identity equality, declaration
+syntax, presence cases, and operation tables belong in the
+[configuration contract](../config.md#strict-document-composition).
+
+## Ownership And Confidentiality
 
 Returned configuration and metadata must not share mutable state across loads.
 ConfigKit must not mutate a result after returning it. Ordinary exported Go
@@ -143,12 +403,12 @@ forwarded blindly when they can include raw input. Do not log configuration
 implicitly. Applications remain responsible for classifying their secrets and
 for safe messages supplied by their hooks.
 
-## Scope boundaries
+## Scope Boundaries
 
 Do not introduce automatic directory discovery, network providers, arbitrary
 merge strategies, additional configuration languages, or application runtime
 management without concrete consumer evidence and an explicit design decision.
-The [deferred scope](../roadmap/deferred.md#explicit-non-goals-and-deferred-scope)
-owns the deferred-feature inventory. Significant boundary
-changes require an ADR and corresponding policy/contract updates; implementation
-convenience alone is not a reason to broaden the public API.
+Record significant decisions to exclude capabilities, and their rationale, in
+ADRs. Significant boundary changes require an ADR and corresponding
+policy/contract updates; implementation convenience alone is not a reason to
+broaden the public API.

docs/policy/documentation.md

@@ -1,140 +1,179 @@
 # Documentation Policy
 
-**Base Policy Version:** 1.1
+**Base Policy Version:** 1.11
 
-**Last Updated:** 2026-09-26
+**Last Updated**: 2026-10-16
 
-Licensing ownership incorporates the upstream documentation policy v1.5;
-unrelated policy revisions remain outside this adoption.
+**Upstream Source:** [Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/docs/policy/documentation.md)
 
 ## Purpose
 
-Assign each documentation topic one canonical owner so ConfigKit's documentation
-remains accurate and useful to consumers, maintainers, and implementation agents.
+This policy assigns each documentation topic to one canonical owner. Its goal is
+to keep ConfigKit's documentation accurate, concise, discoverable, and resistant
+to drift for consumers, maintainers, developers, and coding agents.
 
-## Core rules
+## Core Rules
 
-### One canonical owner
+### One Canonical Owner
 
-Each authoritative fact belongs in one owning document or Go declaration's
-reference documentation. Other documents may summarize and link to that owner;
-they must not maintain competing definitions of commands, API contracts, YAML
-semantics, defaults, paths, diagnostics, or compatibility guarantees.
+Each authoritative fact belongs in one document. A non-owning document may give
+a short, stable summary for orientation, but it must link to the canonical owner
+for volatile details.
 
-### Policies, current behavior, and future work
+Volatile details include commands, flags, configuration fields and defaults,
+module keys, schemas, file names, paths, status codes, retry behavior, and
+runtime guarantees. If readers could reasonably treat a statement as a
+contract, maintain it only in the owning document.
 
-- Policies state currently binding contributor rules, including constraints on
-  future implementation. They do not imply that features already exist.
-- Current API/configuration contracts, consumer guidance, and component
-  documentation describe implemented behavior only, including partial boundaries.
-- ADRs record accepted decisions and rationale. Acceptance is not evidence of
-  implementation; execution status belongs in roadmaps.
-- Roadmaps own unimplemented targets, deferred work, and execution status.
+### Current And Future Behavior
 
-Future implementation plans own their task order, acceptance gates, and progress;
-`docs/roadmap/deferred.md` owns deliberate exclusions, not execution instructions.
-As behavior lands, move its normative definition into the current contract and
-replace the roadmap definition with a link. Retire completed roadmap material
-as part of release preparation; ADRs preserve significant decision history.
+Outside `docs/roadmap/`, documentation describes implemented behavior only.
+Partial features may be described only to their implemented boundary.
 
-### Audience and examples
+Architectural constraints may govern future changes. Describe current structure
+from implemented behavior.
 
-Consumer documentation explains how to use the library and what consumers own.
-Internal documents explain mechanisms and dependencies. Keep implementation
-mechanics out of consumer guidance unless they affect a meaningful choice.
+ADRs may record an accepted architectural decision before implementation. The
+roadmap owns implementation status and sequencing until the decision is
+implemented. Current architecture, user, operator, integration, and internal
+documentation are updated when the behavior lands.
 
-Complete copyable artifacts belong in `examples/`; Go API examples may live in
-executable Go example tests beside the relevant package. Prose should use the
-smallest useful excerpt and link to the maintained artifact. Examples must be
-secret-free and checked against implemented behavior. Clearly label illustrative
-future syntax in roadmaps; do not present it as a runnable current example.
+`docs/roadmap/future.md` owns potential enhancements and their open questions;
+task-specific plans own execution order and progress. Record significant
+architectural exclusions and their rationale in ADRs. Do not maintain a roadmap
+inventory of rejected proposals. Completed plans retire during release preparation.
 
-### Security and privacy
+### Audience And Detail
 
-Do not include real credentials, private keys, environment dumps, sensitive input,
-or private infrastructure details unless intentionally public. Document secret
-handling, not secret values.
+Write for the document's stated audience and include only the detail needed for
+its owned topic. Keep user and operator docs focused on using and operating the
+application. Developer docs should link to user-facing and external contracts
+for their definitions.
 
-## Canonical ownership
+### Examples
 
-| Topic | Owner | Boundary |
-| --- | --- | --- |
-| Product orientation | `README.md` | Current status, purpose, navigation, and a minimal working example |
-| Contributor entry point | `docs/development.md` | Reading guide and actual baseline validation commands |
-| Architecture rules | `docs/policy/architecture.md` | Responsibilities, dependency constraints, invariants, and scope boundaries |
-| Agent rules | `docs/policy/agents.md` | Implementation discipline, proportionality, rules against inventing contracts, and local commit authorization; not application contracts or architecture |
-| Documentation rules | `docs/policy/documentation.md` | Ownership and document lifecycle |
-| Testing rules | `docs/policy/testing.md` | Risk-based sufficiency, test boundaries, and maintenance principles |
-| Release rules | `docs/policy/release.md` | Compatibility, integrity, gates, immutability, and exceptions |
-| Licensing and attribution rules | `docs/policy/oss.md` | Project licensing conventions, attribution format, notice links, discoverability, and maintenance |
-| Project grant | `COPYRIGHT` | Project identity, holders and years, SPDX expression, grant, disclaimer, and third-party statement |
-| Project license texts | `LICENSE` | Complete selected license and incorporated companion text |
-| Upstream attribution | `docs/oss/attribution.md` | Component names, copyright statements, license identification, and source/license/notice links |
-| Standard dependency license texts | `docs/oss/licenses/` | Complete verbatim texts, not project-specific upstream notices |
-| Release procedure | `docs/release.md` | Exact maintainer commands, prerequisites, supported targets, and verification |
-| Exported Go API | Go documentation beside declarations | Symbol contracts, errors, ownership, and lifecycle API behavior |
-| YAML and resolution semantics | `docs/config.md` | Syntax, composition, precedence, conversion, secret references/bootstrap, and explanation semantics; Go reference docs link here for shared rules |
-| Consumer walkthroughs | `docs/consumers/`, when useful | Task-oriented usage and consumer responsibilities, not duplicate API reference |
-| Component inventory | `docs/internal/overview.md` | Implemented components and links to their owners |
-| Component mechanics | Other `docs/internal/` files, when needed | Detailed implementation behavior and change recipes |
-| Architectural decisions | `docs/adr/` | Context, decisions, alternatives, consequences, and supersession history |
-| Deferred scope | `docs/roadmap/deferred.md` | Deliberate exclusions and the conditions for reconsidering them |
-| Future implementation plans | Task-specific files under `docs/roadmap/` | Unfinished work, task order, acceptance gates, and progress; completed plans retire to Git history |
-| Historical release notes | `docs/releases/` | Version-specific historical summaries required by release policy |
-| Complete examples | `examples/` and executable Go examples | Maintained artifacts; prose links instead of duplicating full examples |
+Complete copyable files belong in `examples/`. Documentation may use the
+smallest illustrative snippet needed to explain its owned topic, but should link
+to maintained examples for complete copyable files.
 
-A listed owner is not a requirement to create an empty file before it has useful
-content. Create API, consumer, example, and component documents when the corresponding behavior
-exists and there is useful content to own. Link only to existing files; use plain
-code paths for planned files. Unvalidated candidate and publication work has the
-explicit temporary exception recorded in the release policy.
+Executable Go API examples may live beside the relevant package.
 
-ConfigKit has no owned HTTP service, application CLI, or runtime operations
-interface. Do not create those reference documents for consuming applications.
+Examples must be valid, secret-free, and tested where practical. Commands and
+configuration used in documentation should match the application.
 
-## Boundary rules
+### Security And Privacy
 
-The [OSS policy](oss.md) owns licensing and attribution conventions. COPYRIGHT
-owns the project grant, LICENSE owns its complete texts, and attribution entries
-own component-specific information. README and new release documents provide
-navigation; the release procedure owns concrete release URLs and publication
-mechanics. Do not duplicate notice lists in those documents.
+Documentation and examples must not contain real credentials, private keys,
+private environment dumps, sensitive source material, or private infrastructure
+details unless intentionally public. Document secret-handling mechanisms, not
+secret values.
 
-Architecture owns governing constraints; ADRs explain why; contracts describe
-implemented semantics; internal documentation explains how. A roadmap may link
-to all of them but must not become a second current reference.
+## Canonical Ownership
 
-Release policy owns guarantees; the release procedure owns commands. A release
-note cannot redefine a compatibility contract or replace a current-documentation
-update. The note at an immutable tag is that release's historical record.
+| Topic | Canonical owner | Owned content | Content owned elsewhere |
+| --- | --- | --- | --- |
+| Product orientation and minimal example | `README.md` | Purpose, current status, shortest useful Go example, and navigation, including licensing and attribution. | Full Go API and configuration contracts, release procedure, and implementation detail. |
+| Contributor entry point | `docs/development.md` | Task-oriented reading guide, contributor orientation, baseline validation commands, and canonical links. | Package inventory, architecture rules, subsystem behavior, detailed change recipes. |
+| Application architecture policy | `docs/policy/architecture.md` | System shape, normative ownership, dependency direction, boundaries, invariants, safety properties, and non-goals. | Concrete package inventory, implementation mechanics, contributor procedures, decision history, future work. |
+| Policy-set provenance and upstream navigation | `docs/policy/meta.md` | Policy-set origin, local authority, adoption baselines, and upstream adoption and update links. | Task-specific reading triggers, detailed adoption procedures, and formal attribution notices. |
+| Agent policy | `docs/policy/agents.md` | Proportionate, idiomatic implementation; rules against inventing requirements, restrictions, guarantees, or policy. | Application contracts, architecture, testing policy, and contributor procedures. |
+| Documentation policy | `docs/policy/documentation.md` | Documentation ownership, audience boundaries, maintenance rules, and ADR/document lifecycle. | Application architecture or product behavior. |
+| Testing policy | `docs/policy/testing.md` | Test philosophy, risk sufficiency, boundaries, doubles, coverage, regressions, and test maintenance. | Subsystem behavior, application contracts, subsystem-specific test inventories, and implementation plans. |
+| Release policy | `docs/policy/release.md` | Versioning, compatibility, release integrity and immutability, release documentation, proportionate gates, publication controls, completion, and required versus optional checks. | Repository-specific commands, product installation guidance, CLI version semantics, historical release summaries, and CI implementation detail. |
+| Open source licensing and attribution policy | `docs/policy/oss.md` | License defaults and author choices, COPYRIGHT and attribution formats, license/notice links, discoverability, maintenance, and concrete exceptions. | Component entries, license texts, release commands, and dependency security review. |
+| Project copyright and license grant | `COPYRIGHT` | Project identity, copyright holders and years, SPDX expression, code grant, separately licensed document scope, warranty disclaimer, and third-party statement. | Complete license texts and upstream component attribution. |
+| Project license texts | `LICENSE` | Complete project and incorporated companion license texts, with required project-specific fields. | General licensing policy and upstream component attribution. |
+| Upstream component attribution | `docs/oss/attribution.md` | House Format entries for dependencies and adapted documents: identity, material scope, copyright, license, notices, and source links. | General policy, exception reasoning, and complete standard license texts. |
+| Standard license texts | `docs/oss/licenses/` | Complete, verbatim standard license texts shared by applicable entries, including copied documentation. | Project-specific upstream notices, attribution prose, and policy interpretation. |
+| Repository-specific release procedure | `docs/release.md` | Maintainer prerequisites, candidate preparation, validation and publication commands and automated guards, asynchronous deliverables, delivery status, optional consumer verification, and recovery. | General release requirements, product installation guidance, historical release summaries, and current compatibility contracts. |
+| Exported Go API | Go documentation beside declarations | Symbol contracts, errors, ownership, and lifecycle behavior. | Shared YAML semantics and complete examples. |
+| Configuration contract | `docs/config.md` | YAML syntax, composition, precedence, schema, defaults, resolution, validation, secrets, and explanation semantics. | Go symbol contracts, complete examples, and implementation detail. |
+| Consumer guidance for the public Go API | `docs/consumers/` | Task-oriented public Go API usage, minimal examples, and consumer responsibilities. | Go symbol contracts, configuration semantics, and internal implementation detail. |
+| Inventory of implemented internal packages | `docs/internal/overview.md` | Implemented packages and components, responsibilities, and links to focused internal docs. | Normative architecture, contributor reading policy, external contracts. |
+| Behavior and architecture of internal packages | Other files under `docs/internal/` | Implementation flow, collaborators, state transitions, package-local guarantees and failures, and relevant tests. | Global architecture invariants, configuration definitions and defaults, external schemas, operator procedures. |
+| Architectural decision records | `docs/adr/` | Significant decisions, context, alternatives, rationale, consequences, and supersession history. | Current behavior reference, implementation status, task sequencing. |
+| Potential future features | `docs/roadmap/future.md` | Candidate enhancements and open questions for future consideration. | Rejected proposals, architectural decisions, task execution, and current behavior. |
+| Future implementation plans | Task-specific files under `docs/roadmap/` | Unfinished work, sequencing, acceptance, and progress; completed plans retire during release preparation. | Implemented behavior and ADR rationale. |
+| Release-note history | `docs/releases/` | One checked-in summary per source release under the procedure; the note at its immutable tag is the release record. | Current commands, behavior, contracts, and compatibility definitions. |
+| Complete examples | `examples/` and executable Go examples | Maintained copyable artifacts and Go API examples. | Configuration reference, symbol contracts, and prose explanation. |
 
-This policy owns what documentation may disclose. Architecture owns security
-invariants. Current configuration and Go API contracts own secret-classification
-and rendering behavior when implemented; internal docs own their mechanisms.
+Create supporting documents for existing interfaces and responsibilities when
+substantive content is available.
 
-## Architectural decision records
+Do not create empty owners.
 
-Use sequential filenames, such as `0001-separate-composition-and-overlay.md`,
-and the lightweight Nygard structure: title, status, date, context, decision,
-alternatives considered, and consequences.
+## Boundary Rules
 
-Accepted decision content is immutable. A changed decision requires a new ADR
-and a superseded status/link in the old one. Navigation links may be repaired
-when specification ownership moves without rewriting historical rationale.
-Rejected architectural alternatives belong in ADRs; deferred or rejected product
-features belong in roadmaps. Do not create an ADR for every routine choice.
+### Orientation
 
-## Maintenance and verification
+Link among orientation, architecture, and internal documents; maintain each
+package or behavior description in its canonical owner.
 
-Update the owning current documentation in the same change that implements or
-changes behavior. When ownership moves, remove the old definition and preserve
-useful navigation links.
+### Go API And Configuration
+
+Go declaration documentation owns exported symbol behavior. The configuration
+contract owns shared YAML and resolution semantics. Consumer guidance explains
+tasks and links to those contracts.
+
+### Releases
+
+The release policy defines requirements and invariants that every release must
+satisfy. The repository-specific release procedure defines the commands and
+workflow maintainers use to satisfy that policy. Release notes record history
+at immutable tags. Maintain current behavior in its canonical documentation,
+update it with the corresponding behavior changes, and keep release procedures
+consistent with adopted policy.
+
+### Project Licensing And Upstream Attribution
+
+README and release documents link to the canonical licensing and attribution
+materials under the [OSS policy](oss.md). The release procedure owns URL
+construction and publication mechanics.
+
+### Contracts And Implementation
+
+Go API and configuration documents define externally observable behavior.
+Internal documents explain implementation and link to the owning contract.
+
+### Security Topics
+
+This policy owns what documentation and examples may contain. Architecture owns
+application security invariants. The configuration and public API contracts own
+secret-classification, bootstrap, and rendering behavior. Internal docs own
+implementation mechanisms only.
+
+## Architecture Decision Records
+
+Use sequentially numbered ADR filenames such as
+`0001-record-architecture-decisions.md`. Follow the lightweight Nygard format:
+
+1. title;
+2. status;
+3. date;
+4. context;
+5. decision;
+6. alternatives considered;
+7. consequences.
+
+Treat the decision content of an accepted ADR as immutable. When a decision
+changes, create a new ADR and update the earlier ADR's status to superseded.
+Rejected architectural alternatives and significant architectural exclusions
+belong in ADRs. Roadmaps preserve plausible future work, not rejected product
+ideas. Routine choices and rejected suggestions need no ADR unless they
+represent a significant architectural decision.
+
+## Maintenance
+
+When behavior changes, update its canonical owner in the same change. If
+ownership moves, remove the old definition and replace it with a link where
+navigation remains useful.
 
 Before completing documentation work:
 
-- verify claims against the implementation or clearly identify future design;
-- check changed local links, paths, fragments, examples, and commands;
-- preserve the distinction between policy, decisions, target behavior, and status;
-- check canonical ownership and remove stale or duplicate definitions;
-- inspect formatting and whitespace;
-- ensure no sensitive data was introduced.
+- verify affected behavior and examples;
+- check commands, flags, fields, defaults, schemas, and paths against their
+  implementation;
+- keep unimplemented behavior in the roadmap, subject to the ADR exception;
+- remove stale references and validate links;
+- confirm that non-owning documents summarize and link rather than redefine;
+- confirm that no secrets or sensitive private data were added.

docs/policy/meta.md

@@ -0,0 +1,27 @@
+# Policy Set Provenance
+
+**Base Policy Version:** 1.0
+
+**Last Updated**: 2026-09-28
+
+**Upstream Source:** [Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/docs/policy/meta.md)
+
+## Origin And Local Authority
+
+This repository's policy set is adapted from
+[Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy).
+The adopted local policies govern work in this repository. Upstream revisions
+become local policy through deliberate adoption, preserving local decisions.
+Each policy's `Upstream Source` identifies its adopted baseline.
+
+## Adoption And Updates
+
+For policy adoption, upstream revision reviews, and updates, consult the
+[upstream adoption and update guide](https://gitea.maximumdirect.net/eric/policy/src/branch/main/docs/adoption.md).
+That guide and the reference example collection are maintained upstream and
+accessed through links. Keep discovery links pointed at the current upstream
+project and guide; keep adopted-source and example links pinned to commits.
+
+The local [developer guide](../development.md) routes tasks to applicable
+policies. Formal credit and licensing notices for the copied policy material
+belong in the local [attribution document](../oss/attribution.md).

docs/policy/oss.md

@@ -1,26 +1,33 @@
 # Open Source Licensing And Attribution Policy
 
-**Base Policy Version:** 1.2
+**Base Policy Version:** 1.8
 
-**Last Updated**: 2026-09-26
+**Last Updated**: 2026-09-28
 
-## ConfigKit applicability
+**Upstream Source:** [Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/docs/policy/oss.md)
+
+## ConfigKit Applicability
 
 ConfigKit's selected grant is LGPL-3.0-or-later, recorded in
 [COPYRIGHT](../../COPYRIGHT), with the complete LGPLv3 and incorporated GPLv3
-texts in [LICENSE](../../LICENSE). Adoption does not change that grant.
-The [release procedure](../release.md) owns the Gitea source host, source-only
-Go module distribution, and annotated-tag publication mechanism. No separate
-hosted download page or license asset is required for this source-only channel.
+texts in [LICENSE](../../LICENSE). The [release procedure](../release.md)
+owns source-only Go module publication through Gitea. No separate hosted release
+object or license asset is required for this channel.
 
 ## Purpose And Scope
 
 This policy defines project licensing conventions and a repeatable House Format
 for upstream attribution and license notices. It covers the project's own code
-and upstream components incorporated into or distributed with the project,
-including relevant transitive dependencies and
-copied code or assets. Treatment follows the component's terms and actual use,
-rather than its classification as a direct dependency.
+and upstream components incorporated into or distributed with the application
+or library, including relevant transitive dependencies and copied code,
+documentation, or assets.
+Determine treatment from the component's terms and actual use.
+
+Consulting development guidance or using tooling alone does not require an
+attribution entry. Copying or adapting documentation for inclusion in the
+repository is different: preserve its applicable attribution and license terms.
+A material's role as development guidance does not exempt copied documents.
+Apply any express permissions for attribution-free reuse of example formatting.
 
 The baseline is a publicly available source repository with releases published
 alongside it. The format is independent of language, forge, and build system.
@@ -31,18 +38,25 @@ compatibility, or resolve every obligation arising from use or distribution.
 
 The [documentation policy](documentation.md) assigns ownership:
 
-- `COPYRIGHT` contains the project name, copyright statements, SPDX expression,
-  license grant, warranty disclaimer, and statement about third-party material.
+- `COPYRIGHT`: project name, copyright statements, SPDX expression, grant,
+  warranty disclaimer, and third-party statement.
 - `LICENSE` contains the complete, unmodified project license text, including
   incorporated companion text. Dependency attribution does not relicense the project.
-- `docs/oss/attribution.md` contains the canonical component entries.
-- `docs/oss/licenses/` contains complete, verbatim standard license texts,
-  including companion texts where applicable.
+- `docs/oss/attribution.md`: canonical component entries.
+- `docs/oss/licenses/`: complete, verbatim standard and applicable companion texts.
 
 Use recognizable license filenames, such as `Apache-2.0.txt` or `LGPL-3.0.txt`.
 A shared standard text may serve multiple entries. Keep explanations outside
 license texts and preserve distinct versions and exceptions.
 
+## Upstream Reference Examples
+
+Use the commit-pinned upstream examples to create actual project notices.
+Retain their links and keep the example collection upstream; keep applicable
+license texts locally as specified above. The
+[standard license-text collection](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/docs/oss/licenses/README.md)
+identifies the available reference texts.
+
 ## Project Licensing
 
 Unless the author specifies otherwise, use **GPL version 3 or later**
@@ -57,10 +71,12 @@ license unless the author deliberately changes it. For mixed-purpose projects,
 follow the author's selected scope rather than inferring different licenses for
 individual packages.
 
-Keep project name, years, and holders accurate in COPYRIGHT; do not assume the
-maintainer owns every contribution or advance years automatically. For another
-selected license, adapt the grant, SPDX expression, disclaimer, and text
-references together.
+Use the upstream [application COPYRIGHT example](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/examples/licensing/application/COPYRIGHT)
+or [library COPYRIGHT example](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/examples/licensing/library/COPYRIGHT)
+to create the project’s root `COPYRIGHT` file.
+Use verified project names, contribution years, and copyright holders.
+For another selected license, adapt the grant, SPDX expression, disclaimer, and
+text references together to reflect the author's selected grant.
 
 For GPLv3 projects, copy the complete GPLv3 text into `LICENSE`. For LGPLv3
 projects, place the complete LGPLv3 text followed by the complete GPLv3 text in
@@ -75,40 +91,70 @@ fields; the standard reference collection remains unchanged. Keep `COPYRIGHT`,
 grant. This convention introduces no blanket requirement for per-file headers;
 preserve notices or add them where the applicable terms require them.
 
+Identify separately licensed documentation or assets in the project grant, with
+links to their attribution and license information. An application's default
+code license does not override the terms of incorporated documentation.
+
 ## Upstream Attribution House Format
 
-Each component entry has five fields:
+Begin `docs/oss/attribution.md` with `# Open Source Attribution Notices`,
+followed directly by component entries. These comprise the complete document.
 
-1. **Project name**, normally as the entry heading.
+Each entry presents these five fields in order, with blank lines between them:
+
+1. **Project name** as a level-two heading. An optional identification paragraph
+   may follow, such as `Selected module: MODULE at VERSION.` with the module and
+   version in backticks. For copied documentation, a concise `Material:` sentence
+   may identify the affected files and whether they were adapted or copied
+   without modification. A factual qualifier such as `(transitive dependency)`
+   is permitted. Limit optional identification prose to factual component and
+   material scope.
 2. **Upstream copyright statement or statements**, preserving their wording.
-3. **SPDX license identifier or expression**, when applicable.
-4. **License and notice links**, covering the applicable standard texts and
-   upstream project-specific material.
-5. **Source repository link**, identifying the source corresponding to the
-   imported version.
+   Put multiple statements in separate paragraphs. Include this field when the
+   selected upstream source supplies an applicable statement; otherwise, omit it.
+3. **SPDX license identifier or expression**, when applicable, using
+   `SPDX-License-Identifier: EXPRESSION`.
+4. **License and notice links**, beginning `License and notices:`, separated
+   by ` | `, and ending with a period. Label local standard texts by license
+   name, such as `MIT` or `Apache 2.0`. Label upstream files by their actual
+   filenames, such as `COPYRIGHT`, `LICENSE`, `NOTICE`, or `PATENTS`.
+5. **Source repository link**, rendered exactly as `[Source](COMMIT_URL).`.
 
-The [go-yaml entry](../oss/attribution.md#go-yaml-v4) demonstrates this format
-with the pinned module's actual statements and links.
+Use the upstream [attribution example](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/examples/licensing/attribution.md)
+to create the project’s `docs/oss/attribution.md`.
+The example illustrates omitted fields and multiple copyrights and licenses.
+Replace the uppercase placeholders and illustrative URLs with actual component
+information. Local license links are relative to the destination
+`docs/oss/attribution.md`; copy the applicable texts into its `licenses/`
+directory. Do not copy example entries for components the project does not use.
 
-These are five fields, not a line limit. Include multiple statements and links
-where needed. Omit the SPDX field when no applicable identifier exists; identify
-nonstandard terms accurately through the linked text. Preserve licensing
-alternatives and exceptions, and record a selected option when relevant. Do not
-invent an identifier or silently resolve an unsettled licensing choice.
+These are five fields, not a line limit. Omit the SPDX field when no applicable
+identifier exists; identify nonstandard terms through the linked text. Preserve
+licensing alternatives and exceptions, and record a selected option when
+relevant through the factual license identification. Do not invent an identifier
+or silently resolve an unsettled licensing choice.
+
+Keep entries factual. Do not add agent-authored explanations of license
+expressions, file-level license scope, research performed, retained source
+notices, or compliance conclusions. Avoid filler such as "none is invented
+here" and embellished link labels such as "upstream LICENSE", "additional
+patent grant", or "at the imported commit". Preserve actual required upstream
+content; this rule excludes editorial additions, not required notices. Policy
+interpretation and exception reasoning belong in the adopted OSS policy or an
+appropriate decision record, not the attribution document.
 
 ## License Texts And Upstream Links
 
 Link standard license texts to their local copies. Link project-specific
-notices to the upstream copies instead of storing them locally. Every upstream
-repository or notice link must identify the exact commit corresponding to the
+notices to their upstream copies. Every upstream repository or notice link must
+identify the exact commit corresponding to the
 imported version, including the selected source revision for copied material.
-Do not use moving branches or version tags as substitutes for that commit.
 
-Classify material by its contents, not its filename. An upstream `LICENSE`,
+Classify material according to its contents. An upstream `LICENSE`,
 `COPYING`, or similar file may contain project-specific notices or exceptions
 in addition to standard wording. Link both the local standard text and the
 commit-specific upstream file when needed. Make companion license texts directly
-reachable from the entry rather than leaving readers to infer their location.
+reachable from the entry.
 
 For project-specific license and attribution material, this policy accepts
 direct links to the applicable upstream texts as satisfying reproduction,
@@ -124,10 +170,9 @@ source files; the central attribution entry does not authorize stripping them.
 ## Discoverability
 
 End the project's README with two friendly statements linking to its actual
-grant in `COPYRIGHT` and the attribution document. ConfigKit's [README](../../README.md)
-uses "ConfigKit is licensed under the LGPL v3.0 or later" and "Open Source
-attribution notices are available", linking the license name to COPYRIGHT and
-the attribution phrase to `docs/oss/attribution.md` relative to the repository root.
+grant in `COPYRIGHT` and the attribution document. ConfigKit's
+[README](../../README.md) contains the two required statements: one linking to
+the project grant and one linking to attribution.
 
 Each new checked-in release document and its hosted download page must end
 with links whose visible text is `COPYRIGHT | LICENSE | ATTRIBUTION`. Use absolute
@@ -159,8 +204,10 @@ to implement this policy.
 Use the House Format routinely. Raise an exception only for a concrete obligation
 or unresolved rights question it does not address, including any arising from a
 particular distribution channel. Record the issue and selected treatment in the
-adopted policy or affected attribution entry as appropriate. Resolve the issue
-before the affected use or distribution without reopening settled choices.
+adopted OSS policy or an appropriate decision record. Attribution entries
+contain the resulting factual identification and required material, without
+repeating that reasoning. Resolve the issue before the affected use or
+distribution without reopening settled choices.
 Common ownership of projects is neither required nor a blanket exception.
 
 Apply the formatting convention prospectively. Do not rewrite published tags,

docs/policy/release.md

@@ -1,45 +1,39 @@
 # Release Policy
 
-**Base Policy Version:** 1.0
+**Base Policy Version:** 1.6
 
-**Last Updated:** 2026-09-26
+**Last Updated**: 2026-10-09
 
-The licensing-footer requirement incorporates upstream release policy v1.2;
-other release-workflow changes from that version are not adopted here.
+**Upstream Source:** [Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy/src/commit/e833faddf120c789a9b45348edaf75720de16348/docs/policy/release.md)
 
 ## Purpose
 
-This policy defines the minimum requirements for selecting, validating,
-publishing, verifying, and correcting releases. Its goal is to make every
-release intentional, reproducible from an exact source revision, documented
-for consumers, and safe from retrospective replacement.
+This policy defines a proportionate workflow for validating and publishing an
+intended source revision under a fresh version. Releases should require little
+routine intervention, avoid repeated work, and preserve published contents.
 
-The repository-specific commands that implement these requirements belong in
-`docs/release.md`. Historical release summaries belong in `docs/releases/`.
-Neither document may weaken this policy.
+Adopt stronger verification or reproducibility requirements through an explicit
+project-specific decision justified by the intended audience and support needs.
 
-## ConfigKit applicability
+The repository-specific commands belong in `docs/release.md`. Historical release
+summaries belong in `docs/releases/`. The procedure must agree with the adopted
+policy and link to it rather than introduce additional release requirements.
 
-ConfigKit adopts a source-only Go module release model. The source tag and
-version-matched release note are the declared deliverables. Standalone binaries,
-container images, and separate binary/package-registry publication are not
-required. This does not waive source compilation, module hygiene, testing, or
-local target-build validation. Post-publication consumer retrieval is optional,
-as documented under Policy Exceptions.
+## ConfigKit Applicability
 
-The release procedure must define the module path, authoritative remote,
-supported Go versions and operating-system/architecture targets, prerequisite
-dependency acquisition, and the exact verification commands once established.
-The default tests themselves remain deterministic and offline. Additional
-publication channels require documented deliverables and verification before use.
+ConfigKit publishes a source-only Go module. Its declared deliverables are the
+immutable annotated source tag and version-matched checked-in release note.
+Standalone binaries, container images, hosted release objects, and separate
+registry publication are not required. Additional channels require a deliberate
+update to the policy and procedure.
 
-The Go API, documented YAML/resolution semantics, and structured diagnostic
-contracts all participate in compatibility review. A signature-preserving change
+The Go API, documented YAML and resolution semantics, and structured diagnostic
+contracts participate in compatibility review. A signature-preserving change
 can still break consumers. Human diagnostic wording is stable only where a
-contract expressly promises it. Minimum Go version and platform support changes
-also require an explicit compatibility assessment.
+contract expressly promises it. Minimum Go version and platform support
+changes also require an explicit compatibility assessment.
 
-### Platform support
+### Platform Support
 
 Linux is the release-validated platform. macOS has best-effort support: keeping
 it working remains desirable, but neither native macOS validation nor Darwin
@@ -48,53 +42,67 @@ does not by itself block a release. Voluntary checks and fixes are welcome; ther
 is no guarantee that each release has been validated on macOS.
 
 The [release procedure](../release.md#release-identity-and-support) owns target
-architectures and required Linux checks. This support change applies to upcoming
-releases; historical release notes and their validation records remain unchanged.
-The v0.3.0 release note must explain the change in Compatibility, with version
-selection following this policy's existing compatibility rules.
+architectures and required Linux checks. Historical release notes and their
+validation records remain unchanged.
 
-## Release Model
+## Release Model And Completion
 
-A release consists of:
+A source release identifies one exact committed source revision through an
+immutable version tag and a version-matched, checked-in release note. The
+primary release branch is `main` unless the adopted policy specifies otherwise.
+The procedure must name the authoritative publication remote.
 
-- one exact source commit reachable from the repository's primary branch;
-- one immutable version tag identifying that commit;
-- one version-matched, checked-in release note; and
-- every artifact, image, package, registry entry, or other deliverable the
-  repository declares for that release.
+A successful push of the intended tag, with its source commit available on the
+authoritative primary branch, completes the release. The source commit may be
+pushed before the tag or published together with it through an atomic push.
+The procedure must choose and document the supported approach.
 
-The repository's primary branch is `main` unless an adopted policy documents
-an exception. A release candidate must be committed and pushed to that branch
-before its release tag is published.
+ConfigKit uses sequential publication: first push the committed candidate to
+authoritative `main`, then invoke ReleaseKit once to validate that candidate and
+publish its annotated tag. The [release procedure](../release.md) names
+`origin`; ReleaseKit checks its exact effective push URL before validation and
+tag publication.
 
-The source tag is the authoritative release identity. Published deliverables
-must be traceable to the tagged source and must agree with its version. A
-repository may publish source only. When it publishes additional deliverables,
-its release procedure must enumerate them and define how each is built,
-identified, published, and verified.
+Release commands must finish at successful publication. They must not wait for
+or poll CI, require successful CI status, inspect downloadable artifacts, or
+check consumer installation or Go module availability as completion gates.
+A failed or ambiguous push requires resolving the authoritative remote state
+before declaring success or retrying; successful pushes do not require a
+separate remote read-back gate.
 
-Release automation may validate or publish a release only when its exact
-responsibility is documented. Automation must not silently change the source
-candidate, move a published tag, replace a published deliverable, or repair a
-release in place.
+Remote tag read-back and fresh consumer retrieval are optional and non-gating
+after successful publication. A failed push receives one bounded check of the
+authoritative ref; do not poll or blindly retry.
 
-A successful push of the intended annotated tag completes the source-only release.
-Never wait for CI or use its status as a readiness or completion gate. Optional
-post-publication checks must not delay reporting success.
+Repositories may publish source only. Additional binaries, images, packages,
+checksums, or other declared deliverables may be published asynchronously from
+the tagged source. The procedure must identify those deliverables and the
+responsibility of their automation. Published deliverables must be traceable
+to that source and identify the same version.
+
+ConfigKit currently declares no additional deliverables. Confirmed publication
+of the intended source tag is the completion point. CI, macOS validation,
+hosted delivery, and consumer retrieval are outside the release gates.
 
 ## Versioning And Compatibility
 
 Stable releases use Semantic Versioning in the form `vMAJOR.MINOR.PATCH`, with
-no leading zeroes. Each version must be unused locally and in every configured
-remote or publication channel before publication begins.
+no leading zeroes. Prereleases require an explicit adopted policy defining
+their format and use.
 
-Unless an adopted policy explicitly supports and defines prereleases,
-prerelease versions are not permitted.
+ConfigKit does not support prereleases.
+
+The selected version must be unused locally and on the authoritative remote.
+Do not require queries to every configured remote or publication service.
+A version known to have already been published must not be reused, even if the
+normal guards do not inspect that channel. Adding a distribution channel
+requires a deliberate update to the policy and procedure where needed.
 
 For releases at or after `v1.0.0`:
 
 - a major release may make intentional incompatible changes;
-- a minor release may add backward-compatible behavior; and
+- a minor release may add backward-compatible behavior or raise the Go consumer
+  minimum as described below; and
 - a patch release may make backward-compatible fixes.
 
 Before `v1.0.0`, a minor release may change a documented public, operational,
@@ -102,157 +110,210 @@ configuration, data, integration, or compatibility contract when the release
 note explains the impact and required consumer action. A patch release must
 not intentionally break those contracts within its minor line.
 
-A repository with additional compatibility promises must define them in its
-adopted policy or canonical contract documentation. A release note may explain
-a compatibility change, but it must not redefine the current compatibility
-contract.
+Additional compatibility promises and deliberate exceptions belong in the
+adopted policy or canonical contract documentation. Release notes explain
+changes; they do not redefine current compatibility contracts.
 
-## Release Documentation
+## Consumer Minimum And Release Toolchain
 
-Every release made under this policy must include
-`docs/releases/<version>.md` in the tagged source tree. The filename must use
-the complete version tag, and the document must begin with a title containing
-the product name and that exact version.
+Distinguish the minimum toolchain supported for consumers from the toolchain
+maintainers use to build and validate a release. Record the consumer minimum in
+the language's standard metadata and explain its support meaning in canonical
+documentation. Define the selected release toolchain and its setup commands in
+`docs/release.md`. Toolchain selection and upgrade cadence are repository-specific
+choices.
 
-Every new release note must contain these sections:
+For Go repositories, normally declare the initial stable release of the selected
+series as the consumer minimum, such as `go 1.26.0`. Use a higher patch minimum
+when a dependency or an identified correctness fix requires it, and document
+the reason.
 
-```markdown
-# <Product> vMAJOR.MINOR.PATCH
+For release-policy purposes, successful build and release validation on the
+selected Go patch release are sufficient to presume support across that Go
+series, subject to the declared consumer minimum and concrete evidence of
+incompatibility. Investigate specific compatibility concerns as they arise.
 
-This release ...
+Use the selected release toolchain for candidate validation and release builds,
+including CI jobs performing those tasks. A newer validation patch version alone
+leaves the consumer minimum unchanged.
 
-## Summary
+A minor release may raise the Go consumer minimum, including from one Go series
+to the next, both before and after `v1.0.0`. This is an explicit exception to the
+backward-compatibility requirement for minor releases. Patch releases preserve
+the consumer minimum. Explain an increase's impact and required consumer action
+in the release note. Other incompatible changes remain subject to the versioning
+rules above.
 
-## Compatibility
+### ConfigKit Toolchain Selection
 
-## Upgrade
+For minor and major releases, select the newest stable Go series available in
+the development environment. For patch releases, retain the series recorded in
+`go.mod` and its consumer minimum. Use the latest locally available compatible
+patch in the selected series, with `GOTOOLCHAIN=local`, to build the
+module-selected ReleaseKit CLI and validate the candidate. The same Go
+executable builds the tool and runs its validation commands.
 
-## Changes
-```
+## Release Documentation And Preparation
 
-Use an explicit statement such as "No action required" when a section has no
-substantive content.
+Every new release must include `docs/releases/<version>.md` in the tagged
+source tree. Use the complete version tag as the filename and begin with a
+title containing the product name and that exact version.
 
-Release notes are immutable historical summaries. They should link to current
-canonical documentation for exact behavior. Every affected canonical document
-must be updated in the same candidate; a release note must not substitute for
-current documentation or defer required documentation changes.
+ConfigKit requires the first line `# ConfigKit <version>`. ReleaseKit's
+publication guard checks the release-note H1 for the product and version.
 
-Each new release note must end with the release navigation defined by the
-[OSS policy](oss.md#discoverability). Preserve those links on a hosted download
-page if one is used. The release procedure owns URL construction and channel
-treatment. This is ordinary preparation, not a new network check or approval
-gate; historical release notes are unchanged.
+Include a short summary and any relevant compatibility impact or upgrade
+instructions. Choose sections suited to the release and keep the note
+proportionate to the change.
 
-## Candidate Preparation And Validation
+Keep exact current contracts in their canonical documents and update affected
+documentation with the behavior change. Link to those documents from the note
+where useful. If annotated tags are used, derive their summary from the
+checked-in note.
 
-ConfigKit provides one local release checker. Run it once against the final
-committed candidate using one maintained patch of the minimum supported Go line
-on Linux. It checks module hygiene, formatting and whitespace, the full offline
-suite with the race detector, static analysis, and CGO-disabled Linux amd64/arm64
-builds. Examples, documentation links, consumer fixtures, and package boundaries
-are covered by that suite, not separate repeated runs. Native package compilation
-is covered by the test run. A second toolchain is optional and non-gating.
+ConfigKit uses the complete checked-in note as the annotated tag message.
 
-Commit the release note and associated changes before release validation. Record
-the exact validated commit; revalidate if the candidate changes. Do not require
-both pre-commit and post-commit full checker runs for unchanged content.
-Do not publish uncommitted or unvalidated content. Local check failures still
-block publication. Skipped test cases are reported, not separate human sign-off
-requirements.
+Include the release footer defined by the [OSS policy](oss.md#discoverability)
+in each new release document. The release procedure defines the concrete URLs
+and publication mechanics. Prepare these links with the release note; they do
+not add a network check or approval gate. If a hosted download page is used in
+a future channel, preserve the footer there.
 
-Compatibility review, release-note accuracy, removal of completed roadmaps, and
-review for unintended files, credentials, private data, and unrelated changes
-are ordinary preparation. The executing agent may perform them without routine
-human approval or separate manual evidence records. Ask the maintainer only for
-genuine unresolved decisions or missing authority. A clean existing checkout is
-sufficient; a dedicated clone is optional. Dependency and toolchain update
-research belongs to maintenance or relevant changes, not every release.
+Handle version selection, release-note content, and retirement of completed
+roadmaps during preparation. Preserve planned and deferred work and repair
+affected links when retiring roadmaps. Reuse ordinary change review for
+unintended files, credentials, and private data. Scope release-content review
+to the tagged source.
+
+## Candidate Validation
+
+Provide one publication command that validates the final committed candidate,
+checks publication state, and publishes the intended refs. A validation-only
+mode or command may be provided for diagnosis, but must not be a required step
+before publication repeats the same checks.
+
+ConfigKit uses the module-selected ReleaseKit CLI's `publish
+vMAJOR.MINOR.PATCH` command. Its `check` command is optional for diagnosis; it
+is not a required preliminary pass to publication.
+
+Run the complete deterministic, offline default test suite once for the final
+candidate, following the [testing policy](testing.md). For repositories that
+publish builds, verify the required build targets. Select those targets for
+the application's actual support commitments; native testing on each platform
+and access to particular hardware are not default release prerequisites.
+
+Prepare dependencies and build the tool before offline validation; the
+publication command is the required validation run, with no separate successful
+test or CI run required before it.
+
+The selected profile runs the complete deterministic, offline default suite
+once with the race detector and test-time vet disabled. The suite already
+includes examples, consumer fixtures, documentation links, and package
+boundaries. One full vet pass adds static checks beyond the test-time subset.
+CGO-disabled Linux amd64 and arm64 package compilation covers supported
+configurations distinct from native race compilation. macOS and newer-toolchain
+checks are optional.
+
+Additional gates must address a concrete risk that the existing checks do not
+adequately cover. Do not automatically require linting, race testing, module
+hygiene audits, documentation audits, credential scans, example validation, or
+expanded platform matrices solely because they are possible. Retain such
+checks when their distinct protection justifies their cost. A one-time migration
+check must not silently become a permanent release requirement.
+
+ReleaseKit runs its selected Go commands with readonly module mode and
+`GOPROXY=off`; acquire dependencies and build the tool before candidate
+validation. Formatting and whitespace remain ordinary development checks in
+`scripts/check.sh`.
+Review module tidiness when dependencies change, not as a release gate.
+
+Release tests must not require real credentials, mutable application services,
+paid APIs, provider probes, or inference calls. The procedure may describe dependency
+preparation separately from offline validation.
+
+Avoid duplicate validation across release phases. Successful checks for the
+same final candidate need not be repeated solely to satisfy another phase;
+any reuse must clearly apply to that exact candidate. Persistent validation
+caches are not required. If the candidate changes, validate the new candidate.
+Cheap publication-state checks may be repeated immediately before pushing
+because local or remote state may have changed during validation.
+
+Automate mechanical guards. Human review gates are strongly disfavored: add one
+only through an explicit project-specific policy decision explaining the
+concrete risk and why ordinary change review or automation is insufficient.
+Do not add routine confirmations for checks the command can perform itself.
+
+Compatibility review, release-note accuracy, completed-roadmap retirement, and
+review for unintended files or credentials remain ordinary preparation. The
+executing agent may perform them without routine human approval or separate
+manual evidence records. Publication itself requires authorization.
 
 ## Publication Guards
 
-Immediately before publication, the maintainer or release automation must
-fetch the current primary branch and tags from the authoritative remote and
-verify all of the following:
+Automate the checks needed to publish the intended source under a fresh version:
 
-- the version has the required format and is not already published;
-- the current branch is the primary release branch;
-- the worktree and index are clean;
-- the current commit is the recorded, validated candidate;
-- the authoritative remote branch points to that same commit;
-- the matching release note exists in that commit and has the required title
-  and sections;
-- release publication is authorized and the local automated gates succeeded for
-  that commit; and
-- no local or remote tag already uses the selected version.
+- the version has the adopted format and is unused locally and on the
+  authoritative remote;
+- the worktree and index are clean on the primary release branch;
+- the source being published is the exact candidate that passed validation,
+  including its matching release note H1;
+- the remote primary branch can be advanced to that candidate without
+  discarding remote history, and is published before the tag; and
+- the tag identifies the validated candidate and only the intended refs are
+  published.
 
-Create the version tag against the guarded commit and verify its target before
-publishing it. Publish only the exact intended ref and deliverables. Broad
-operations such as `git push --tags` are discouraged because they can publish
-unreviewed refs unrelated to the release.
+ReleaseKit checks that `origin`'s effective push URL exactly matches the
+authoritative URL before candidate validation. This does not assert the
+configured fetch URL or require the release-note H1 to be the first line; the
+required `# ConfigKit <version>` first-line format remains a content rule. The
+command checks the candidate and unused version again after validation, and
+checks local state before creating the tag. Ignored local files do not block
+publication.
 
-The repository-specific procedure must make these guards executable or give
-copyable commands for performing them.
+Fetch the authoritative branch and tag state as needed for these checks.
+Do not force branch or tag updates to bypass a failed guard. Publish explicit
+refs rather than all local tags. Do not require CI success, publication-service
+availability checks, or a separate manual confirmation for each guard.
 
 ## Immutability And Correction
 
-Published version tags and published deliverables are immutable. Do not move,
-overwrite, recreate, or delete a published tag. Do not replace an artifact,
-image, package, checksum, signature, provenance statement, or release note
-under an already published version.
+Published version tags and published contents are immutable. Do not move,
+overwrite, recreate, or delete a published tag, or replace a published artifact,
+checksum, signature, provenance statement, or release note under that version.
+The checked-in note at the immutable tag is that release's historical record.
 
-If validation fails before publication, correct the candidate, rerun the
-complete gates, and repeat the publication guards. An unpublished local tag
-may be removed after confirming that it was never published or used by a
-release channel.
+If validation fails before publication, correct and commit the candidate and
+rerun the publication command. If a push fails or its outcome is ambiguous,
+inspect the authoritative remote before retrying. Remove an unpublished local
+tag only after confirming it was never published or used by a release channel.
+An unavailable remote leaves publication status unknown; do not overwrite a tag
+to resolve uncertainty.
 
-If publication or post-publication verification reveals a defect, leave the
-published release intact. Correct the defect on the primary branch, choose a
-new patch version or other semantically appropriate new version, write a new
-matching release note, and perform the complete release procedure again.
+Transient network, authentication, CI, or consumer-availability failures do not
+by themselves require a new version.
 
-A distribution channel's supported yank, deprecation, or advisory mechanism
-may warn consumers away from a defective release, but it must not replace that
-release's contents or reuse its version.
+A defect requiring changes to published source or contents requires a corrected
+commit, a new semantically appropriate version, a matching release note, and
+the release procedure again. Leave the original release intact. A channel's
+yank, deprecation, or advisory mechanism may warn consumers away from a defective
+release without replacing its contents or reusing its version.
 
 ## Repository Release Procedure
 
-Every adopting repository must maintain `docs/release.md` as the canonical
-maintainer runbook for implementing this policy. It must define, in execution
-order:
+Maintain `docs/release.md` as a short, executable maintainer runbook. It must
+identify prerequisites, the selected release toolchain, the primary branch and
+authoritative remote, version and note preparation, one publication command with
+local checks and guards, source-only deliverables, the successful-tag-push
+completion point, and partial or unknown-state recovery.
 
-1. maintainer prerequisites and required access;
-2. version selection and compatibility review;
-3. release-note creation;
-4. candidate preparation and commit;
-5. one local validation pass, exact candidate recording, and push;
-6. publication guards;
-7. exact tag and deliverable publication commands;
-8. completion on successful tag push and optional post-publication checks; and
-9. failure handling and correction.
-
-The procedure should use copyable, fail-fast commands where practical. It must
-name the primary branch, authoritative remote, tag form, published
-deliverables, supported build targets, release automation responsibilities,
-and optional consumer verification path. It must link to this policy instead of
-restating or redefining its requirements.
+Use copyable commands where practical. Keep optional diagnostics and consumer
+verification clearly optional. The procedure must not turn preparation work,
+ordinary change review, or post-publication investigation into additional
+release gates.
 
 ## Policy Exceptions
 
-Any exception to this policy must be explicitly documented in this section,
-including the repository constraint requiring it, its rationale, scope, and
-compensating controls. Customizing release mechanics must not silently weaken
-the policy's integrity, validation, documentation, verification, or immutability
-requirements.
-
-For ConfigKit's source-only releases, the maintainer accepts successful publication
-of the intended tag as sufficient completion evidence. This is an explicit
-exception to the shared standard's mandatory post-publication verification:
-authoritative tag read-back and fresh consumer retrieval are optional and
-non-gating. CI status and downstream retrieval availability must not delay release
-completion. Compensating controls are local validation of the exact candidate,
-automated pre-publication guards, matching remote main, verification of the local
-annotated tag target, explicit ref pushes, and immutable published versions.
+The following historical exceptions do not change the current release workflow.
 
 For v0.1.1 only, the maintainer approved renaming the reserved `_configkit` key to
 `configkit` as an error-correcting point release because there are no current
@@ -266,6 +327,3 @@ For v0.2.0 only, the maintainer accepted the successful native macOS check at
 only. The final candidate still requires the complete Linux release checker.
 This exception waives only repeating the macOS check after those documentation
 changes; it does not waive other publication or verification gates.
-
-Candidate selection and guarded publication remain mandatory; post-publication
-verification is optional in the [release procedure](../release.md).

docs/policy/testing.md

@@ -1,14 +1,16 @@
 # Testing Policy
 
-**Base Policy Version:** 1.0
+**Base Policy Version:** 1.3
 
-**Last Updated:** 2026-09-06
+**Last Updated**: 2026-09-28
+
+**Upstream Source:** [Standard Repository Policies](https://gitea.maximumdirect.net/eric/policy/src/commit/d84a38ebab26f048cafbe59a2246700c35d29843/docs/policy/testing.md)
 
 ## Purpose
 
 Our tests exist to make **incorrect changes expensive and correct changes cheap**.
 
-We do not optimize for test count, line coverage, exhaustive isolation, or the fewest possible tests. We optimize for sufficient confidence in important behavior while imposing as little unnecessary friction as possible on future development.
+We optimize for sufficient confidence in important behavior while minimizing friction on future development.
 
 ## ConfigKit-specific priorities
 
@@ -44,32 +46,19 @@ policy does not imply that those tools or tests already exist.
 
 ## Every test has a cost
 
-Testing is not an unqualified good. Every test imposes both an immediate cost and a continuing lifetime cost.
-
-A test must be:
-
-- written and reviewed;
-- understood by future maintainers and coding agents;
-- executed in local and CI workflows;
-- diagnosed when it fails;
-- updated when legitimate behavior changes;
-- maintained as fixtures, APIs, and dependencies evolve; and
-- removed or rewritten when it becomes redundant, brittle, misleading, or obsolete.
-
-Tests also create cognitive and architectural friction. They can constrain refactoring, duplicate policy, slow feedback loops, add noise to failures, and cause harmless implementation changes to require unrelated edits across the suite.
+Every test has an immediate and continuing cost: writing, review, execution,
+diagnosis, fixture maintenance, and updates when legitimate behavior changes.
+Tests can also constrain refactoring, duplicate policy, and add failure noise.
 
 A test is warranted only when the confidence it provides justifies these costs.
-
-Apply this cost-benefit analysis at two levels:
+Evaluate that tradeoff at two levels:
 
 1. **Per test:** What realistic defect does this test detect, how consequential would that defect be, and is that protection worth the test's lifetime cost?
 2. **Across the suite:** Does this collection provide materially more confidence than a smaller, simpler suite would?
 
-The preferred test suite is a **lean suite that provides sufficient confidence in the risks that matter, without redundant or low-value tests**. We seek sufficient confidence with the least unnecessary testing friction, not the fewest possible tests.
+Some friction is intentional. Tests should make dangerous changes—such as breaking compatibility, corrupting data, violating security boundaries, or reintroducing subtle bugs—require deliberate review. Keep ordinary internal changes inexpensive.
 
-Some friction is intentional. Tests should make dangerous changes—such as breaking compatibility, corrupting data, violating security boundaries, or reintroducing subtle bugs—require deliberate review. They should not make ordinary internal changes needlessly expensive.
-
-The cost of a test is not a reason to omit testing by default. Do not cite maintenance cost abstractly. When omitting a plausible test, be able to state why the protected failure is low-risk, already covered, obvious, reversible, or cheaper to detect elsewhere. For consequential, subtle, or difficult-to-observe behavior, the presumption should favor testing.
+Evaluate maintenance cost against the specific failure being protected. When omitting a plausible test, be able to state why the protected failure is low-risk, already covered, obvious, reversible, or cheaper to detect elsewhere. For consequential, subtle, or difficult-to-observe behavior, the presumption should favor testing.
 
 ## Default testing style
 
@@ -81,6 +70,8 @@ Use a **classical/Detroit-style** approach:
 - Prefer package-level behavioral tests over tests coupled to private helpers or internal call sequences.
 - Treat exact collaborator interactions as testable behavior only when the interaction itself is a requirement.
 
+Examples of appropriate seams include clocks, randomness, subprocesses, remote APIs, object storage, email, and paid LLM calls.
+
 For ConfigKit, controlled input readers and filesystem failures are useful seams.
 Prefer actual parsing, composition, and decoding over mocks of their call order.
 
@@ -92,7 +83,7 @@ Control clocks, randomness, environment variables, and other process-global or m
 
 ## What deserves tests
 
-Prioritize tests for:
+To the extent the following features are present in the application, prioritize tests for:
 
 1. Public and package-level contracts.
 2. Domain rules and important invariants.
@@ -102,15 +93,27 @@ Prioritize tests for:
 6. Previously observed or plausible regressions.
 7. Representative integration and end-to-end workflows.
 
-A package-level contract is behavior relied upon by another package or major collaborator, not every observable detail of a package implementation.
+A package-level contract comprises behavior relied upon by another package or major collaborator.
 
-For behavior involving **data integrity, destructive operations, compatibility, security, concurrency, idempotency, or recovery**, presume that durable tests are required unless the behavior is already credibly protected at another layer.
+Choose tests for requested behavior and established contracts. Tests must not
+introduce new restrictions, guarantees, or threat scenarios merely because they
+could be asserted. Follow the [agent policy](agents.md) when deciding whether a
+behavior belongs to the contract; current implementation behavior alone is not
+sufficient authority.
+
+For established behavior involving **data integrity, destructive operations,
+compatibility, security, concurrency, idempotency, or recovery**, favor durable
+tests for realistic failures whose consequences warrant protection. Identify
+the failure and the existing contract it would violate. These categories call
+for attention, not an automatic test inventory or permission to strengthen the
+application's guarantees. Account for protection already provided at other layers.
 
 Do not add tests merely because a function, branch, or line exists. Do not add a test when the same meaningful risk is already adequately protected elsewhere.
 
 ## Choose the right test boundary
 
-Test through the narrowest stable boundary that expresses the behavior clearly.
+Choose the narrowest stable boundary that expresses the behavior clearly and
+provides durable confidence with minimal incidental coupling.
 
 This is often the package API, but it may instead be:
 
@@ -118,28 +121,15 @@ This is often the package API, but it may instead be:
 - a package-level operation when several internal collaborators jointly produce the behavior; or
 - a larger integration boundary when correctness emerges from interaction with a real dependency.
 
-Do not force all behavior through oversized end-to-end tests. Do not test every private helper merely because it exists. Choose the boundary that gives durable confidence with the least incidental coupling.
-
 ## Test behavior, not implementation
 
-A test should protect a decision, contract, or invariant—not memorialize the current implementation.
+A test should protect a selected decision, contract, or invariant.
 
-Before adding or retaining a test, ask:
+A test is suspect when it primarily detects changes to private constants or
+helpers, equivalent operation ordering, incidental formatting, equivalent
+algorithms, or internal structure that preserves behavior.
 
-> What realistic defect would this test catch?
-
-A test is suspect when its main purpose is to detect that someone:
-
-- changed an internal constant;
-- renamed or split a private helper;
-- reordered equivalent internal operations;
-- changed incidental formatting;
-- replaced one correct algorithm with another; or
-- refactored internal object structure without changing behavior.
-
-Refactoring should normally require no test edits unless the refactored structure is itself part of the contract.
-
-A test can be factually correct and still have negative value. Accurately describing current behavior is not enough; the protected behavior must be important enough to justify the future friction.
+Behavioral tests should normally remain stable through internal refactoring that preserves the contract.
 
 ## Expected effects of different changes
 
@@ -156,12 +146,13 @@ A test failing is not the same as a test needing to be edited. Many tests may co
 
 ## Separate mechanism from policy
 
-Configurable thresholds and defaults must not be duplicated throughout the test suite.
+Derive expectations from test-controlled configuration and relationships.
 
-For example, do not encode an internal concurrency limit indirectly:
+For this example, assume the selected contract rejects a request to start more
+processes than a configured limit. Do not encode its production default indirectly:
 
 ```go
-// Production policy:
+// Production default:
 const maxConcurrency = 4
 
 // Brittle test:
@@ -179,25 +170,30 @@ require.NoError(t, runner.Start(limit))
 require.ErrorIs(t, runner.Start(limit+1), ErrTooMuchConcurrency)
 ```
 
-The test should prove:
+For this selected contract, the test should prove:
 
 - the configured limit is accepted; and
 - one beyond the configured limit is rejected.
 
+Rejection is not a general requirement for concurrency control. If the selected
+contract queues excess work or limits active workers while accepting larger
+batches, test that behavior instead. Do not add rejection or a configurable
+limit solely to reproduce this example.
+
 The production default should be tested exactly only when its literal value is itself a public, operational, safety, protocol, or compatibility requirement.
 
-Apply the same rule to limits, timeouts, capacities, retry counts, and ranges: test relationships and behavior, not duplicated literals.
+Apply the same rule to limits, timeouts, capacities, retry counts, and ranges: test relationships and behavior.
 
-For concurrency limits, test both kinds of behavior when relevant:
+For established concurrency limits, distinguish these behaviors where the contract requires them:
 
-1. **Configuration enforcement:** invalid or excessive requested values are handled correctly.
+1. **Configuration handling:** values are accepted or rejected according to the selected contract.
 2. **Runtime enforcement:** observed peak concurrency never exceeds the configured limit.
 
-Use a test-controlled limit and measure the behavior relative to that limit. Do not merely assert today's default value.
+Use a test-controlled limit and measure the behavior relative to that limit.
 
-## Avoid semantic duplication across layers
+## Assign each behavior a test owner
 
-Each behavior should have a clear test owner.
+For ConfigKit, assign ownership as follows:
 
 - YAML boundary tests own syntax and policy enforcement.
 - Composition and overlay tests own their operation semantics.
@@ -209,9 +205,7 @@ Each behavior should have a clear test owner.
 
 These are responsibility boundaries, not a required package layout.
 
-Higher-level tests should not repeat every lower-level case. A single intentional policy change should not require unrelated edits across many test files.
-
-Tests that are individually reasonable may still be collectively redundant. Evaluate the marginal value of each additional test in light of the protection already provided by the rest of the suite.
+Give each layer its distinct responsibility and keep expectation updates localized to the contract being changed.
 
 ## Use test doubles deliberately
 
@@ -232,104 +226,77 @@ Mocks are appropriate when the contract includes facts such as:
 - an expensive API is called no more than once; or
 - a security audit event is emitted.
 
-Do not use mocks merely to isolate every object or reproduce the implementation's call graph.
-
 ## Go-specific guidance
 
-Use:
+Select techniques by behavior and risk:
 
 - table-driven tests for meaningful behavioral categories and boundaries;
 - `t.TempDir()` for real filesystem behavior;
-- fuzz tests for parsers, normalization, path handling, and broad input spaces;
+- `httptest.Server` for realistic HTTP interactions;
+- fuzz tests when exploring broad input spaces, such as parsers or path handling, adds useful protection beyond representative cases;
 - golden files only when the complete output is intentionally stable;
 - integration tests where correctness depends on component interaction; and
-- a small number of representative end-to-end tests.
+- a small number of representative end-to-end tests when assembled workflows expose meaningful risks not adequately covered at narrower boundaries.
 
-Avoid exact error-string assertions unless the wording is itself contractual. Prefer `errors.Is`, `errors.As`, typed errors, or structured error fields.
+Prefer `errors.Is`, `errors.As`, typed errors, or structured error fields. Use exact error-wording assertions only when the wording is contractual.
 
 At the public library boundary, prefer diagnostic codes, paths, and source
 locations over complete message snapshots. Assert wording only when contractual.
 
 Golden-file updates must require an explicit local flag. CI must not update golden files automatically, and reviewers must inspect the semantic diff before accepting an update.
 
-Keep tests readable and direct. Test helpers and fixture frameworks must earn their own maintenance cost; do not build elaborate test infrastructure for small or isolated needs.
+Keep tests readable and direct. Size test helpers and fixture frameworks to the maintenance benefit they provide.
 
 ## Coverage
 
-Coverage is a diagnostic, not a target.
+Use coverage to locate untested critical branches and unexpectedly weak packages. Evaluate test quality through meaningful behavioral protection and choose coverage according to risk.
 
-Use it to find untested critical branches and unexpectedly weak packages. Do not write low-value tests solely to increase a percentage, and do not infer test quality from coverage alone.
-
-Dense configuration semantics will often warrant higher coverage than simple input wiring. Uneven coverage is acceptable when it reflects risk.
-
-Increasing coverage is valuable only when the newly covered behavior protects a meaningful risk at an acceptable cost.
+Pure domain logic will often warrant higher coverage than CLI wiring or external adapters. Uneven coverage is acceptable when it reflects risk.
 
 ## Regression tests
 
 A bug fix should normally include a regression test that fails before the fix and passes afterward.
 
-Retain the test when the defect could realistically recur and its consequences justify the ongoing cost. Prefer the narrowest durable test of the violated contract or invariant; do not preserve accidental implementation details from the original bug.
+Retain the test when the defect could realistically recur and its consequences justify the ongoing cost. Prefer the narrowest durable test of the violated contract or invariant.
 
-Not every historical bug requires a permanent test. If the underlying design has made recurrence impossible, the test has become redundant, or a stronger invariant test now subsumes it, remove or consolidate it.
+Remove or consolidate a test when the underlying design has made recurrence impossible, its protection is redundant, or a stronger invariant test subsumes it.
 
 ## Deleting or rewriting tests
 
-Tests are maintained code, not permanent historical artifacts.
-
-Delete or rewrite a test when its maintenance cost exceeds the confidence it provides.
+Delete or rewrite tests when maintenance cost exceeds their continuing
+protective value.
 
 Strong candidates include tests that:
 
 - require updates after harmless internal changes;
-- directly assert private constants without protecting a real contract;
-- duplicate the same policy across several layers;
+- assert incidental private constants or snapshot large amounts of incidental output;
 - verify mock choreography rather than outcomes;
-- snapshot large amounts of incidental output;
-- test trivial private helpers already exercised through stable package behavior;
-- protect risks already covered more effectively elsewhere;
+- duplicate policy across layers, retest trivial helpers covered by package
+  behavior, or protect risks covered more effectively elsewhere;
 - are flaky, misleading, obsolete, or disproportionately expensive to diagnose; or
 - no longer correspond to a plausible failure mode.
 
-Several brittle tests may encode one genuine requirement. Replace them with one durable behavior-level or invariant test rather than preserving all of them.
-
-Deleting a low-value test can improve the quality of the suite by reducing noise, maintenance burden, and friction around legitimate change.
+Several brittle tests may encode one genuine requirement. Consolidate them into one durable behavior-level or invariant test.
 
 ## Reviewing a proposed test
 
-Use the following questions when the value, boundary, or durability of a proposed test is not self-evident. Significant test additions should be reviewable against them, but written answers are not required for every routine test.
+Use the following questions when a proposed test needs closer evaluation. Significant test additions should be reviewable against them; written answers are optional for routine tests.
 
-1. What realistic defect would it catch?
-2. How likely is that defect?
-3. How consequential would it be?
-4. Is the behavior already protected elsewhere?
-5. At which layer should this behavior be owned?
-6. Does the test assert a durable contract or an incidental implementation detail?
-7. Could the implementation be refactored without changing the behavior and without editing this test?
-8. What should cause this test to fail?
-9. What legitimate changes should not cause this test to fail?
-10. What ongoing maintenance, execution, and diagnostic cost will the test impose?
-11. Is there a smaller or more direct test that protects the same risk?
-
-Do not add the test when its expected lifetime cost exceeds its expected protective value.
-
-When deciding not to test plausible behavior, record or be able to explain why the risk is low, already protected, obvious, reversible, or cheaper to detect elsewhere.
+1. Which requested behavior or established contract does it protect, and what realistic defect would violate it?
+2. How likely and consequential is that defect, and is it already protected elsewhere?
+3. What is the narrowest stable boundary that can test it clearly?
+4. Would a correct internal refactor or a change to an incidental default require test edits?
+5. Does its confidence justify its maintenance, execution, and diagnostic cost, or would a smaller test suffice?
 
 ## Definition of sufficient
 
 A test suite is sufficient when:
 
-- important contracts and invariants are protected;
-- meaningful boundaries and failure modes are exercised;
-- realistic and consequential regressions are credibly protected against silent recurrence;
-- behavior involving data integrity, destructive operations, compatibility, security, concurrency, idempotency, and recovery is credibly protected;
-- important external boundaries have realistic integration coverage;
-- representative complete workflows are tested;
-- failures provide useful signal rather than redundant noise;
-- legitimate internal changes usually do not require test edits; and
+- important requested behavior and established contracts are protected against realistic, consequential failures;
+- boundaries and component interactions have coverage where they introduce meaningful risks not protected elsewhere;
+- failures provide useful, distinct signals;
+- tests usually remain stable through legitimate internal changes; and
 - additional tests would mostly repeat existing protection or preserve inconsequential implementation details.
 
-Sufficiency is a risk judgment, not a coverage percentage or test count. Reassess it as the library, its consumers, and the consequences of failure evolve.
-
-The governing rule is:
-
-> Test heavily where failure is consequential, subtle, or difficult to detect after the fact. Test lightly where failure is obvious, reversible, and inexpensive—and retain no test whose lifetime cost exceeds the confidence it provides.
+Reassess sufficiency as the application, its users, and the consequences of
+failure evolve.

docs/release.md

@@ -1,252 +1,237 @@
 # ConfigKit Release Procedure
 
 This is the maintainer runbook for ConfigKit's [release policy](policy/release.md).
-ConfigKit publishes one source-only Go module: the immutable source tag and the
-matching checked-in release note are the deliverables. There is no application
-binary, container image, generated package, or separate registry publication.
+ConfigKit publishes a source-only Go module. The immutable annotated tag and
+matching checked-in release note are the deliverables; there is no binary,
+container image, generated package, or separate registry publication.
 
 ## Release identity and support
 
 - Module: `gitea.maximumdirect.net/eric/ConfigKit`
 - Primary branch: `main`
-- Authoritative remote: `origin`, expected to fetch from
-  `https://gitea.maximumdirect.net/eric/ConfigKit.git`
-- Tags: stable Semantic Versions such as `v0.1.0`; prerelease tags are not supported
-- Minimum Go language/toolchain line: Go 1.25, release-validated with one maintained
-  patch of that line; newer-toolchain testing is optional and non-gating
-- Release-gated build targets: Linux on amd64 and arm64
-- Best-effort targets: macOS on amd64 and arm64, under the
+- Authoritative remote: `origin`
+- Authoritative push URL: `https://gitea.maximumdirect.net/eric/ConfigKit.git`
+- Tags: stable Semantic Versions such as `v0.5.0`; no prereleases
+- Minimum Go version: the first stable patch of the selected Go series, or a
+  higher patch when required by a dependency or specific correctness fix, as
+  recorded in `go.mod`; see the
+  [consumer minimum policy](policy/release.md#consumer-minimum-and-release-toolchain)
+- Release-gated targets: Linux amd64 and arm64
+- Best-effort targets: macOS amd64 and arm64, under the
   [platform support policy](policy/release.md#platform-support)
 
-The local Linux checker includes native race tests and CGO-disabled cross-builds.
-Its output reports skipped filesystem cases; no separate evidence record or
-human sign-off is required. Native macOS checks and Darwin cross-builds are
-optional and do not gate publication.
+Release validation runs one offline race-enabled Go suite, one full vet pass,
+and CGO-disabled package compilation for both Linux targets. macOS and CI are
+not release gates; do not wait for or poll CI.
 
-CI is never a release gate. Do not wait for it, poll its status, or delay reporting
-completion because it is pending, unavailable, or failed.
+## 1. Select Go and prepare the tool
 
-## 1. Prepare access and tools
+Use a clean checkout with Git, Bash 3.2 or newer, and a native compiler for race
+tests. Choose the release type before selecting Go. For a minor or major release,
+select the newest stable Go series available in the development environment.
+For a patch release, retain the series recorded in `go.mod` and leave its consumer
+minimum unchanged. Follow the
+[toolchain selection policy](policy/release.md#configkit-toolchain-selection).
 
-The release maintainer owns this procedure. Use a clean checkout (a dedicated clone is optional) with Git, Bash 3.2 or newer,
-a maintained Go 1.25 patch, and the compiler needed for native race tests. The checker supports the stock macOS
-Bash; its filename enumeration is null-delimited, including names with whitespace. Configure private-host Git and Go module
-access through the normal credential manager before starting. Keep tokens, passwords,
-SSH material, and environment dumps outside the repository and command transcript.
-Verify access without displaying credentials:
+Put the selected series' latest locally available compatible patch first on
+`PATH`, ensuring it meets `go.mod`'s minimum. The same `go` executable must build
+ReleaseKit and run its child validation commands. Set local toolchain selection
+and verify it:
 
 ```sh
-git remote get-url origin
-git ls-remote origin HEAD
+export GOTOOLCHAIN=local
+go version
+go env GOVERSION
+command -v go
 ```
 
-The remote URL must equal the authoritative URL above. Acquire the selected
-toolchain and dependencies explicitly. For example, with the maintained patch
-used when this procedure was simplified:
+Only when a minor or major release advances the consumer minimum to a newer Go
+series, derive that series' initial stable release from the selected executable:
 
 ```sh
-export CONFIGKIT_BASELINE_TOOLCHAIN=go1.25.14
-GOTOOLCHAIN="$CONFIGKIT_BASELINE_TOOLCHAIN" go version
-GOTOOLCHAIN="$CONFIGKIT_BASELINE_TOOLCHAIN" go mod download
+selected_go=$(GOTOOLCHAIN=local go env GOVERSION)
+selected_series=${selected_go#go}
+selected_series=${selected_series%.*}
+release_minimum="$selected_series.0"
+go mod edit -go="$release_minimum"
 ```
 
-Keep toolchains maintained, but do not require latest-version discovery for each
-release. The checker sets `GOPROXY=off` and fails if the cache is incomplete.
-Toolchain and YAML-dependency update research belongs to periodic maintenance or
-relevant dependency changes. No renewed approval of an unchanged pin is required.
+If a dependency or identified correctness fix requires a higher patch minimum,
+use that required version instead and document the reason. When the series is
+unchanged, leave the minimum unchanged unless a minor or major release
+deliberately changes it under the
+[consumer minimum policy](policy/release.md#consumer-minimum-and-release-toolchain).
+For example, validating with Go 1.26.8 leaves `go 1.26.0` unchanged. There is no
+separate requirement to validate with Go 1.26.0.
 
-Use Bash with `set -euo pipefail` for the command blocks below so any failed gate
-stops the sequence. Publication requires user authorization; the agent policy's
-local-commit authorization is not permission to push or release.
-
-## 2. Select the version and review compatibility
-
-Choose an unused stable version and compare the candidate with the previous tag.
-For the first release, review the whole public surface and current contracts.
+Prepare dependencies whether or not the minimum changes:
 
 ```sh
-release_version=v0.1.0
-printf '%s\n' "$release_version" | grep -Eq '^v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)$'
-if git show-ref --verify --quiet "refs/tags/$release_version"; then exit 1; fi
-if git ls-remote --exit-code --tags origin "refs/tags/$release_version" >/dev/null; then
-  printf 'remote tag already exists: %s\n' "$release_version" >&2
-  exit 1
-else
-  test $? -eq 2
-fi
-git log --oneline --decorate --no-merges
+go mod download
 ```
 
-Review exported Go signatures and ownership, YAML and scalar behavior, precedence,
-diagnostic codes, minimum Go version, and platform support. Before `v1.0.0`, any
-intentional incompatible minor-release change must be explained with consumer action;
-patch releases must remain compatible within their minor line. Review the maintained
-consumer examples and the migration guide even when signatures did not change.
+Build the tool selected by `go.mod` into temporary storage outside the checkout.
+Ensure `$TMPDIR` names a system temporary location, not the repository. These
+commands never install another ReleaseKit version:
 
-When dependencies change, review parser behavior and migration impact as part of
-that change. Keep Compatibility accurate about the dependency pin, but do not
-perform an external version survey for every patch release.
+```sh
+releasekit_tmp=$(mktemp -d "${TMPDIR:-/tmp}/configkit-releasekit.XXXXXX")
+releasekit_bin="$releasekit_tmp/releasekit"
+go build -o "$releasekit_bin" gitea.maximumdirect.net/eric/ReleaseKit/cmd/releasekit
+go list -m gitea.maximumdirect.net/eric/ReleaseKit
+"$releasekit_bin" version
+```
 
-## 3. Write the release note
+The module-selected executable is ReleaseKit v0.4.1. Use the built executable
+for publication to preserve its exit status and publication-state diagnostics.
+`go run` maps a nonzero child exit status to 1. ReleaseKit's child Go commands
+use the `go` found on `PATH` with `GOTOOLCHAIN=local`; keep the selected
+executable first on `PATH` through the publication command.
 
-Create `docs/releases/$release_version.md` before selecting the candidate. It must
-begin with `# ConfigKit $release_version` and contain `Summary`, `Compatibility`,
-`Upgrade`, and `Changes` sections. Use “No action required” where appropriate. Link
-to current canonical contracts instead of copying their definitions. Do not create a
-release note until there is a real candidate and reviewed content.
+Verify access to the authoritative remote without displaying credentials:
 
-End each new release note with the footer required by the
-[OSS policy](policy/oss.md#discoverability). For the selected version, use these
-absolute Gitea URLs (replace every `VERSION` with the complete intended tag):
+```sh
+git ls-remote https://gitea.maximumdirect.net/eric/ConfigKit.git HEAD refs/heads/main
+```
+
+Publication requires explicit authorization. Local implementation commits do
+not authorize a push or release.
+
+## 2. Prepare and commit the candidate
+
+Choose an unused stable version locally and on the authoritative remote. Compare
+the candidate with the previous tag and review exported Go signatures and
+ownership, YAML and resolution semantics, diagnostic contracts, minimum Go
+version, and platform support. Review maintained consumer examples and the
+migration guidance. Explain any consumer-minimum increase and required consumer
+action under the
+[consumer minimum policy](policy/release.md#consumer-minimum-and-release-toolchain).
+
+Create `docs/releases/<version>.md`. Its first line must be exactly
+`# ConfigKit <version>`, and it must end with the license and attribution footer:
 
 ```markdown
 [COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/VERSION/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/VERSION/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/VERSION/docs/oss/attribution.md)
 ```
 
-Confirm the three target files exist in the candidate and the version is correct
-during ordinary note review. The future tag need not resolve remotely yet; do
-not add publication-time network checks. ConfigKit publishes source tags with
-checked-in notes, not separate hosted download pages. If a hosted release page
-is used later, reuse the checked-in note as its body and retain this footer.
-Do not retrofit published notes or add separate downloadable license assets.
+Replace `VERSION` with the full tag and confirm the three target files exist in
+the candidate. Retire completed roadmaps, preserve unfinished and deferred
+work, and repair affected links. Review the complete candidate for unintended
+files and credentials, then commit it on `main`. These are ordinary preparation
+tasks, not separate approval gates. Any `go.mod` change belongs in this
+candidate.
 
-## 4. Validate the source candidate
+## 3. Push the candidate to `main`
 
-Before release validation, finish compatibility review, inspect the diff and file
-list for unintended content or credentials, retire completed roadmaps, repair
-links, and review the release note. These are ordinary preparation tasks the
-executing agent may perform, not separate human approvals or evidence records.
-Ask the maintainer only for an unresolved product decision or missing authority.
-
-Commit the candidate, staging only its intended changes, then run the checker
-once against that clean commit. Do not run both everyday and release checkers to
-repeat the same gates.
+Push only that committed candidate to the literal authoritative URL. This does
+not follow local tags:
 
 ```sh
-git status --short
-# Stage the specific files belonging to the candidate, then review:
-git diff --staged
-git commit --message "Prepare ConfigKit $release_version"
-test -z "$(git status --porcelain=v1 --untracked-files=all)"
-candidate_commit=$(git rev-parse HEAD)
-./scripts/release-check.sh
-test "$(git rev-parse HEAD)" = "$candidate_commit"
-test -z "$(git status --porcelain=v1 --untracked-files=all)"
-printf '%s\n' "$candidate_commit" > "$(git rev-parse --git-path configkit-release-candidate)"
+git push --no-follow-tags https://gitea.maximumdirect.net/eric/ConfigKit.git HEAD:refs/heads/main
 ```
 
-If the final candidate is already committed, omit the staging and commit commands;
-do not create an empty commit. The checker validates module manifests in a
-disposable copy, formatting, whitespace, the full offline suite once with the race
-detector and verbose skip reporting, vet once, and CGO-disabled Linux amd64/arm64
-builds. The suite includes examples, consumer fixtures, documentation links, and
-package boundaries; no separate reruns are required. No additional linter is
-claimed. Sibling-consumer links are checked when those checkouts exist and are
-otherwise inapplicable in an isolated checkout.
+ReleaseKit requires authoritative `main` to equal this candidate before it
+validates. A failure before this push means ReleaseKit publication has not
+started. If the push result is uncertain, inspect authoritative `main` and
+continue only when it is confirmed at the candidate. If validation later fails,
+no release tag is published; correct the issue in a new commit, push the new
+candidate to `main`, and invoke validation again.
 
-A changed candidate requires validation again. Do not reuse a recorded candidate
-from an older revision. The record is written only after successful local checks.
+## 4. Publish the committed candidate
 
-## 5. Prepare publication
-
-The following guarded sequence pushes only `main` and the selected tag. Local
-validation failures block it; CI does not. Keep the selected `release_version`
-from step 2 in the same shell. If starting a new shell, set it explicitly again.
-
-## 6. Run publication guards
-
-Immediately before tagging, fetch the authoritative branch and tags, restore the
-recorded variables if this is a new shell, and execute every guard:
+With the authorized candidate already on authoritative `main`, invoke the
+module-selected native executable exactly once:
 
 ```sh
-candidate_commit=$(cat "$(git rev-parse --git-path configkit-release-candidate)")
-git fetch --prune origin main
-git fetch --tags origin
-test "$(git branch --show-current)" = main
-test -z "$(git status --porcelain=v1 --untracked-files=all)"
-test "$(git rev-parse HEAD)" = "$candidate_commit"
-test "$(git remote get-url origin)" = 'https://gitea.maximumdirect.net/eric/ConfigKit.git'
-printf '%s\n' "$release_version" | grep -Eq '^v(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)\.(0|[1-9][0-9]*)$'
-test -f "docs/releases/$release_version.md"
-test "$(sed -n '1p' "docs/releases/$release_version.md")" = "# ConfigKit $release_version"
-for heading in Summary Compatibility Upgrade Changes; do
-  grep -Fxq "## $heading" "docs/releases/$release_version.md"
-done
-if git show-ref --verify --quiet "refs/tags/$release_version"; then exit 1; fi
-if git ls-remote --exit-code --tags origin "refs/tags/$release_version" >/dev/null; then
-  printf 'remote tag already exists: %s\n' "$release_version" >&2
-  exit 1
-else
-  test $? -eq 2
-fi
-git push origin HEAD:refs/heads/main
-git fetch origin main
-test "$(git rev-parse refs/remotes/origin/main)" = "$candidate_commit"
-test "$(git rev-parse HEAD)" = "$candidate_commit"
-test -z "$(git status --porcelain=v1 --untracked-files=all)"
+"$releasekit_bin" publish vMAJOR.MINOR.PATCH
 ```
 
-The recorded local validation must apply to exactly `$candidate_commit`. No
-separate human sign-off, CI status, or manual evidence document is required.
-
-## 7. Tag and publish the exact ref
-
-Create one annotated tag at the guarded commit, verify its peeled target, and push
-only that ref. Do not use `git push --tags`.
+Replace the placeholder with the selected version. ReleaseKit checks the
+effective push URL against `expected_push_url`, verifies the candidate on
+`main`, and checks the release-note H1 for the product and version. It then
+runs the selected race-enabled standard suite once with test-time vet disabled,
+one full vet pass, and CGO-disabled package compilation for Linux amd64 and
+arm64. It publishes only the annotated tag for that candidate. Confirmed
+publication of the intended tag completes the release. The tag points to the
+captured commit and uses the complete checked-in note as its annotation message.
+The optional `check`
+command is available for diagnosis but is not a separate required pass:
 
 ```sh
-git tag --annotate "$release_version" --message "ConfigKit $release_version" "$candidate_commit"
-test "$(git rev-list -n 1 "$release_version")" = "$candidate_commit"
-git push origin "refs/tags/$release_version:refs/tags/$release_version"
+"$releasekit_bin" check vMAJOR.MINOR.PATCH
 ```
 
-A successful push of the intended tag completes the release. Report success now;
-do not wait for CI, module propagation, or any post-publication check. No Gitea
-release object or binary upload is required.
+Status 0 confirms publication, status 1 reports a known publication failure or
+conflict, status 2 reports usage, profile, or version errors, and status 3 means
+the push outcome remains unknown. Preserve both the native exit status and its
+diagnostics.
 
-## 8. Optional post-publication checks
+The command does not push or repair `main`, wait for CI, or publish binaries or
+a hosted release page. A successful intended-tag publication does not require
+remote read-back or consumer retrieval; those checks remain optional.
 
-Only when useful or requested, read back the remote tag or retrieve the exact
+## 5. Recover from a failed or uncertain tag push
+
+The executable reports the publication state, phase, version, candidate commit,
+tag-object ID, effective endpoint, and error on standard error. It performs one
+bounded authoritative reconciliation after a failed tag push. Exit status 3
+means the tag outcome remains unknown; do not blindly retry or move a tag.
+
+For an uncertain result, use the exact endpoint, candidate commit, version, and
+tag-object ID from the report. Copy the captured endpoint into the variable
+below using normal shell quoting. Check that Git still resolves it to itself,
+then query the authoritative refs once:
+
+```sh
+authoritative='COPY_CAPTURED_ENDPOINT'
+release_version='vMAJOR.MINOR.PATCH'
+test "$(git ls-remote --get-url -- "$authoritative")" = "$authoritative" &&
+  git ls-remote --refs -- "$authoritative" refs/heads/main "refs/tags/$release_version"
+```
+
+A failed URL-equality check or remote query leaves the outcome unresolved.
+Correct transport configuration before continuing; a rewritten destination
+cannot establish absence at the captured endpoint.
+
+Compare the `main` object ID with the reported candidate commit and the tag
+object ID with the reported tag-object ID. `--refs` returns the annotated tag
+object itself, not merely its peeled commit. If the tag object matches, the
+release is published. If the query fails, the result is conflicting, or the
+endpoint or candidate differs, stop and resolve the state before retrying. If
+the endpoint is reachable, the tag is confirmed absent, and `main` still equals
+the reported candidate, remove a retained local tag only after confirming it
+was not published or used by another channel; then rerun `publish`, which
+revalidates the candidate:
+
+```sh
+git tag -d "$release_version"
+"$releasekit_bin" publish "$release_version"
+```
+
+A validation failure after the candidate reached `main` leaves an untagged
+candidate there. Correct it with a new commit rather than rewriting or rolling
+back `main`. A conflicting published tag must never be moved or reused. A
+defect in published source requires a corrected commit, a new semantically
+appropriate version, and a matching release note.
+
+## 6. Optional consumer verification
+
+When useful or requested, read back the remote tag or retrieve the exact
 version into a new module without a local `replace` directive. These checks are
-optional and non-gating; their failure or unavailability does not delay release
-completion. Do not poll CI or wait for module propagation. Private-host credentials
-must already be configured. Example direct-origin verification:
+optional and non-gating. Do not poll CI or wait for module propagation. For
+direct-origin verification, use the exact published version in a temporary
+consumer module:
 
 ```sh
-remote_tag_commit=$(git ls-remote origin "refs/tags/$release_version^{}" | awk '{print $1}')
-test "$remote_tag_commit" = "$candidate_commit"
+release_version=vMAJOR.MINOR.PATCH
 consumer_dir=$(mktemp -d)
 (
   cd "$consumer_dir"
   go mod init example.invalid/configkit-release-check
   GOPRIVATE=gitea.maximumdirect.net GOPROXY=direct go get "gitea.maximumdirect.net/eric/ConfigKit@$release_version"
-  cat > main.go <<'EOF'
-package main
-
-import configkit "gitea.maximumdirect.net/eric/ConfigKit"
-
-func main() {
-        _ = configkit.NoSource()
-}
-EOF
-  gofmt -w main.go
-  go test ./...
-  go build ./...
   go list -m -f '{{.Path}} {{.Version}}' gitea.maximumdirect.net/eric/ConfigKit
 )
-rm -rf -- "$consumer_dir"
 ```
 
-If performed, the final `go list` output should show the exact module path and
-`$release_version`. Report optional verification separately from publication success.
-
-## 9. Handle failures without replacement
-
-Before publication, fix and commit the candidate, validate it, record the new
-exact candidate, and repeat the guarded publication sequence. An unpublished local tag may be deleted only after verifying it
-was never pushed or used by another release channel.
-
-After publication, never move, delete, or recreate the tag and never replace its
-release note. Correct the defect on `main`, choose a new semantically appropriate
-version, and repeat this procedure. A supported advisory or deprecation mechanism
-may warn consumers about the old version but cannot change its contents.
+The output should show the exact module path and selected version. Report this
+optional check separately from publication success.

docs/releases/v0.10.0.md

@@ -0,0 +1,77 @@
+# ConfigKit v0.10.0
+
+This minor release adds explicit, composable discovery of a configuration file.
+Applications choose the search conventions and their order; ConfigKit selects one
+file during loading and returns the final configuration with its normal metadata.
+Optional searches that find no file share the expanded `NoSource()` lifecycle.
+
+## Changes
+
+- Add `SearchConfig`, immutable `Search` and `FilenameGroup` descriptions, and
+  search-wide requiredness through `SearchOptions`. Compose explicit `Paths`,
+  custom `SearchDirectory` descriptions, and built-in Unix system, user-config,
+  home, or working-directory presets with `Searches`. See the
+  [public declarations](../../discovery.go) and
+  [discovery contract](../config.md#configuration-discovery).
+- Expand searches in supplied order, trying a directory's filename groups before
+  moving to the next directory. Named and generic groups provide conventional
+  YAML filenames; custom groups provide literal names. Directory searches
+  distinguish omitted filename selection from an explicitly empty selection.
+  Constructors perform no filesystem access, and each load observes current
+  directory bases and file availability.
+- Select the first existing candidate. Access errors and failures while loading
+  the selected file terminate the load rather than trying another configuration.
+  Selected files retain physical source identity, placement, provenance, imports,
+  and relative-resource context. Discovery works with ordinary loading and
+  layered inputs, including underlays, without adding a precedence tier.
+- Permit enabled imports with an absent main input: there are no main import
+  declarations to traverse, while actual underlay sources retain normal imports.
+  Support ordinary selected overlays with an absent main and explicit filesystem
+  context, including a root-only host context. Layered overlays retain their
+  independent `OverlayFilesystem` requirement. See
+  [single-source loading](../config.md#single-source-loading) and
+  [layered loading](../config.md#layered-loading).
+- Preserve ordinary file-context behavior after discovery and include the
+  failing candidate's file identity in access diagnostics. Use Go's
+  platform-aware Windows component rules and native drive-root-relative path
+  resolution. Isolate user-config tests according to the host Go conventions.
+
+## Compatibility and upgrade
+
+Existing explicit source constructors and loading APIs remain available.
+`File(path)` remains an exclusive selection that fails for a missing file;
+discovery is activated only by explicitly supplying `SearchConfig`.
+
+Searches are optional by default. Set `SearchOptions{Required: true}` when the
+application must find a file. An exhausted optional search contributes no main
+document or source record; application version checks, defaults, resolution,
+and validation still run under their existing rules and may reject incomplete
+configuration. A selected overlay is still required to exist.
+
+The former `NoSource()` rejections of enabled imports and explicit filesystem
+context are relaxed. An active ordinary overlay with no main file now loads
+when explicit context is supplied. Applications that relied on those combinations
+being rejected should review their option handling. Selected host files derive
+their own base directory; do not supply an explicit `BaseDir` or native filesystem
+context for a search that selects a host file.
+
+Applications may replace their own fallback-loading loops with the new search
+descriptions. The maintained [consumer examples](../consumers/README.md#explicit-main-file-discovery)
+show simple preset selection and custom-first discovery alongside existing
+configuration tiers. Composition, collection operations, inheritance, CLI
+precedence, and the complete-on-return ownership model retain their existing
+semantics.
+
+Select this version and rebuild:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.10.0
+```
+
+The consumer minimum remains Go 1.26.0. Release validation uses Go 1.26.10.
+The YAML dependency remains `go.yaml.in/yaml/v4 v4.0.0-rc.6`, and the maintainer
+tool remains ReleaseKit v0.4.1. Linux amd64 and arm64 remain release-validated
+targets; macOS remains best-effort. Publication follows the existing
+[release procedure](../release.md).
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.10.0/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.10.0/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.10.0/docs/oss/attribution.md)

docs/releases/v0.4.2.md

@@ -0,0 +1,45 @@
+# ConfigKit v0.4.2
+
+This patch release simplifies and safeguards source publication and aligns
+maintainer policy and licensing guidance. Library behavior is unchanged.
+
+## Summary
+
+Maintainers can now publish a prepared release with one guarded command. It
+validates the exact committed candidate, checks the authoritative destination,
+and pushes only the candidate on `main` and its annotated version tag. The
+[release procedure](../release.md) explains preparation and partial-publication
+recovery; successful tag publication completes the source-only release without
+waiting for CI or consumer retrieval.
+
+## Compatibility
+
+No Go code, public API, configuration semantics, diagnostic behavior, or
+dependencies changed from v0.4.1. The minimum Go version remains 1.25. Linux
+amd64 and arm64 remain release-validated; macOS remains best-effort. The YAML
+dependency remains `go.yaml.in/yaml/v4 v4.0.0-rc.6`.
+
+## Upgrade
+
+Select this version and rebuild:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.4.2
+```
+
+No application-code or configuration migration is required from v0.4.1.
+
+## Changes
+
+- Add guarded single-command publication with exact candidate, version, and
+  remote checks; note-derived annotated tags; and bounded failed-push recovery.
+- Keep one offline race suite, one full vet pass, and Linux amd64/arm64 builds
+  as release gates. Formatting and whitespace remain development checks;
+  dependency tidiness is reviewed when dependencies change.
+- Align adopted policies and contributor guidance with their pinned upstream
+  revision, and include the CC BY-SA 4.0 license text and attribution for
+  adapted policy material. The project grant remains LGPL-3.0-or-later.
+- Retire completed release-workflow and policy-alignment planning records while
+  preserving their history in Git. Deferred scope remains documented.
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.4.2/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.4.2/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.4.2/docs/oss/attribution.md)

docs/releases/v0.5.0.md

@@ -0,0 +1,53 @@
+# ConfigKit v0.5.0
+
+This minor release adds source-backed layered configuration and built-in sibling
+inheritance, so applications can load one complete configuration while retaining
+presence, source context, and explainable derivation.
+
+## Summary
+
+- `LoadLayered` combines ordered underlay groups beneath the main input, selected
+  overlay, and explicit CLI overrides. Inputs within a group still compose
+  strictly; precedence tiers combine mappings recursively. The main input
+  remains the owner of the optional schema-version check.
+- `NewFilesystem(...).File(...)` accepts caller-owned `fs.FS` sources, and
+  `Mapping(...)` snapshots supported built-in values as a labeled source.
+  `Result.SourceContext` and `Resolution.SourceContext` expose passive resource
+  contexts for values from file-backed sources.
+- `extends` now resolves a mapping against one named sibling after source
+  precedence and before typed decoding. Inherited values count as explicit
+  input. Origins, history, explanations, and redacted rendering retain the
+  source and the structural path by which a value reached its destination.
+  Review corrections preserve immutable nested-history evidence and bounded
+  expansion work.
+
+See the [configuration contract](../config.md#layered-loading),
+[inheritance rules](../config.md#sibling-inheritance), and
+[consumer examples](../consumers/README.md) for current behavior.
+
+## Compatibility and upgrade
+
+This is an intentional pre-v1 incompatible minor release for configurations
+that use `extends` as ordinary data. That key is now reserved wherever an input
+mapping occurs; it is consumed before decoding. Rename any such YAML key and
+corresponding Go field, then rebuild. No collection registration or opt-in flag
+is available. Configurations without `extends` retain their existing meaning.
+
+Applications adopting the new features may move source-backed defaults into
+explicit `Underlay` groups, use `SourceContext` for relative resources, or
+replace application-owned sibling merging with one `extends` relationship per
+mapping. Adoption is optional. The maintained
+[named-preset example](../consumers/README.md#named-sibling-inheritance)
+shows inherited `false` and destination-local nested resolution.
+
+Select the new module version:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.5.0
+```
+
+The minimum Go line remains 1.25. Linux amd64 and arm64 remain the
+release-validated targets; macOS remains best-effort. The YAML dependency is
+unchanged at `go.yaml.in/yaml/v4 v4.0.0-rc.6`.
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.5.0/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.5.0/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.5.0/docs/oss/attribution.md)

docs/releases/v0.6.0.md

@@ -0,0 +1,63 @@
+# ConfigKit v0.6.0
+
+This minor release reduces avoidable configuration-loading and inspection work,
+adopts ReleaseKit for source publication, and raises the consumer Go minimum to
+1.26.0. The public configuration model remains unchanged from v0.5.0.
+
+## Changes
+
+- Reduce temporary path allocations by sizing pointer-formatting buffers,
+  combining final metadata traversal, reusing parsed sensitivity paths, and
+  avoiding path construction when detecting inheritance. Effective and
+  historical metadata indexes retain independently owned paths.
+- Replace repeated resolution-coverage, metadata-update, CLI-overlap, and
+  sensitivity-propagation scans with private indexes and incremental processing.
+  Preserve diagnostic ordering, history, contextual path shapes, and redaction.
+- Make presence-only metadata queries avoid materializing provenance. Prepare
+  resolution replay descriptors and immutable mapping and inheritance-history
+  lookups for inspection, and use ordered membership indexes for provenance
+  collections. Returned records remain detached; explanations still replay
+  complete trees and render on demand.
+- Add a maintained public-API startup construction benchmark. The initial path
+  formatting and metadata traversal experiments reproduced allocation reductions
+  across local and downstream workloads. Later algorithmic improvements were
+  validated behaviorally without a new benchmark campaign. Busy-host timings
+  were inconclusive; no fixed speedup or allocation threshold is promised.
+- Replace ConfigKit-owned release scripts with a small profile and the
+  module-selected ReleaseKit v0.3.0 tool. The
+  [release procedure](../release.md) documents candidate preparation, tag-only
+  publication, and failed-push recovery. Existing release checks and the
+  successful-tag-push completion point remain unchanged; CI is not a gate.
+- Adopt release policy 1.6, distinguishing the consumer Go minimum from the
+  validation toolchain. Retire completed planning and measurement records into
+  Git history while preserving [performance candidates](../roadmap/future.md#3-performance-experiments).
+
+## Compatibility and upgrade
+
+The consumer minimum increases from Go 1.25.0 to **Go 1.26.0**. Install Go 1.26.0
+or newer before upgrading, and update application build and CI environments that
+still use Go 1.25. The `go.mod` directive records the consumer minimum; using a
+newer validation patch does not itself raise that minimum. See the
+[consumer minimum policy](../policy/release.md#consumer-minimum-and-release-toolchain).
+
+Select this version and rebuild:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.6.0
+```
+
+No application-code or configuration migration is required from v0.5.0. Public
+Go signatures, strict within-tier composition, recursive tier precedence,
+sibling inheritance, presence/null distinctions, provenance, secret handling,
+and synchronous completion retain their existing contracts. See the
+[configuration contract](../config.md) and
+[consumer guide](../consumers/README.md).
+
+The YAML dependency remains `go.yaml.in/yaml/v4 v4.0.0-rc.6`. ReleaseKit is a
+declared Go tool dependency for maintainer commands, not a library runtime
+import; its requirements participate in ConfigKit's module graph. Linux amd64
+and arm64 remain release-validated targets, and macOS remains best-effort.
+Maintainers should use the current release procedure instead of the retired
+`scripts/release.sh` and `scripts/release-check.sh` commands.
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.6.0/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.6.0/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.6.0/docs/oss/attribution.md)

docs/releases/v0.7.0.md

@@ -0,0 +1,58 @@
+# ConfigKit v0.7.0
+
+This minor release adds structured comparison of completed configurations.
+Applications can inspect changes between two configuration files or the
+effective impact of a selected overlay, with ConfigKit handling comparison and
+safe value disclosure while applications own presentation.
+
+## Changes
+
+- Add `Diff[T](left, right *Result[T]) ([]Difference, error)` through the public
+  facade. It compares frozen effective inspection values from successful loads,
+  including defaults and recorded application resolution, rather than source
+  text or later mutations of `Result.Config`.
+- Return detached changed-region records containing a semantic path, safe left
+  and right `ValueSnapshot` values, and `HiddenChanged`. Mappings compare
+  recursively, sequences report atomic changes, and records follow canonical
+  pointer order. Presence distinguishes additions and removals from explicit
+  null; equal effective values produce no records regardless of provenance or
+  loading history.
+- Protect both snapshots with sensitivity from both loads, including historical
+  and dependency-derived classification. Compatible regions retain public
+  siblings; incompatible structural replacements use complete-region masking
+  where required. `HiddenChanged` identifies actual changes withheld by masking,
+  rather than merely indicating that a snapshot contains redacted content.
+- Preserve visible public scalar changes when only historical sensitive
+  descendants remain, including additions and removals. Historical explanation
+  redaction and masking of incompatible present shapes remain intact.
+- Add maintained file-comparison and base-versus-overlay examples with
+  consumer-owned formatting, plus an executable public API example. See the
+  [consumer guide](../consumers/README.md#effective-configuration-diffs) and
+  [configuration contract](../config.md#effective-configuration-diffs).
+
+## Compatibility and upgrade
+
+No application-code or configuration migration is required from v0.6.0.
+Adopting the new API is optional. Loading, composition, inheritance, provenance,
+existing inspection, and secret-handling contracts remain unchanged.
+
+Load both configurations successfully before calling `Diff`; nil or
+uninitialized results return an error with no records. Comparison does not
+reopen sources, rerun callbacks, or reread environment variables. Typed secret
+references compare by configured reference name, not resolved credential bytes,
+so credential rotation behind an unchanged name is not reported. Returned
+snapshots describe changed regions, not cross-protected full-document context.
+
+Select this version and rebuild:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.7.0
+```
+
+The consumer minimum remains Go 1.26.0. The YAML dependency remains
+`go.yaml.in/yaml/v4 v4.0.0-rc.6`, and the maintainer tool dependency remains
+ReleaseKit v0.3.0. Linux amd64 and arm64 remain release-validated targets;
+macOS remains best-effort. Publication follows the existing
+[release procedure](../release.md).
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.7.0/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.7.0/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.7.0/docs/oss/attribution.md)

docs/releases/v0.7.1.md

@@ -0,0 +1,22 @@
+# ConfigKit v0.7.1
+
+This patch updates the maintainer release tool to ReleaseKit v0.4.1. ConfigKit's
+runtime behavior and public API are unchanged.
+
+## Compatibility and upgrade
+
+No application-code or configuration migration is required from v0.7.0. The
+consumer minimum remains Go 1.26.0, and the YAML dependency is unchanged.
+
+Select this version and rebuild:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.7.1
+```
+
+ReleaseKit v0.4.1 is a maintainer tool dependency and does not change consumer
+configuration or runtime behavior. Linux amd64 and arm64 remain
+release-validated targets; macOS remains best-effort. Publication follows the
+existing [release procedure](../release.md).
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.7.1/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.7.1/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.7.1/docs/oss/attribution.md)

docs/releases/v0.8.0.md

@@ -0,0 +1,70 @@
+# ConfigKit v0.8.0
+
+This minor release adds explicit input placement, relative import destinations,
+shared source-version checking, and opt-in composition of identified sequence
+records. Applications can assemble independently authored configuration fragments
+into one final configuration while retaining source locations, provenance,
+history, and sensitivity information.
+
+## Changes
+
+- Add `Destination` to ordinary load options and layered inputs. A source mapping
+  can contribute beneath literal application keys without being rewritten by the
+  consumer. Imports inherit that destination or append a relative YAML
+  `destination`. Physical import paths and resource contexts remain relative to
+  their declaring sources. See [input destinations](../config.md#input-destinations),
+  [import syntax](../config.md#explicit-imports), and the
+  [mounted collection example](../consumers/README.md#input-destinations-and-mounted-collections).
+- Add `SourceVersionModeIfPresent` and `SourceVersionModeRequired` to apply one
+  application-owned version checker across main, underlay, imported, and selected
+  overlay documents. Enabled modes check source-local declarations and consume
+  accepted non-main headers before composition. Detached, sensitivity-aware
+  evidence is available through `SourceInfo.VersionCheck`. Acceptance remains
+  application policy; ConfigKit does not require declarations to equal the main
+  version. See [shared source-version checks](../config.md#shared-source-version-checks).
+- Add explicit `PlacementModeSequenceItem` placement for ordinary and layered
+  inputs, and `placement: sequence-item` for path and glob imports. A source
+  mapping becomes one item at its destination; ordinary helper imports compose
+  within that item and can supply its identity. See
+  [imports](../config.md#explicit-imports).
+- Add `Definition.SequenceCompositions` registrations for strict composition at
+  selected literal paths using one string identity field. Distinct records append
+  in contribution order, while duplicate identities conflict. Higher-priority
+  sequences still replace lower-priority sequences wholesale. Registration does
+  not add identity-based overlays or final identity validation after defaults and
+  application resolution. See the [composition contract](../config.md#strict-document-composition)
+  and [maintained prompt catalog](../consumers/README.md#identified-prompt-sequences).
+- Extend source inspection with destination and placement evidence, including
+  whether a nested destination is unresolved in an intermediate or failed-load
+  snapshot. Preserve source-specific history, consumed-header sensitivity, and
+  explanations of descendants removed by sequence replacement as records are
+  assembled. Source locations continue to identify authored coordinates.
+
+## Compatibility and upgrade
+
+The new behavior is opt-in: zero-valued destinations retain root placement,
+mapping placement remains the default, unregistered sequences retain strict
+conflict behavior, and the default source-version mode preserves the existing
+main-only version policy. Recursive mapping precedence, whole-sequence
+replacement between tiers, and application-owned final validation remain intact.
+
+Public option, definition, input, and source-information structs gain fields.
+Consumers using unkeyed literals for affected structs must switch to keyed
+literals or update them. `SourceInfo` now contains a `Path` and is no longer
+comparable with `==` or usable directly as a map key; compare the relevant fields
+or select an application-appropriate key instead. Existing keyed literals need
+no changes to retain the previous loading behavior.
+
+Select this version and rebuild:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.8.0
+```
+
+The consumer minimum remains Go 1.26.0. The YAML dependency remains
+`go.yaml.in/yaml/v4 v4.0.0-rc.6`, and the maintainer tool dependency remains
+ReleaseKit v0.4.1. Linux amd64 and arm64 remain release-validated targets;
+macOS remains best-effort. Publication follows the existing
+[release procedure](../release.md).
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.8.0/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.8.0/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.8.0/docs/oss/attribution.md)

docs/releases/v0.9.0.md

@@ -0,0 +1,111 @@
+# ConfigKit v0.9.0
+
+This minor release expands import selection, adds author-declared collection
+identity and operations, and supports inheritance between identified records.
+It also moves CLI assignments after inheritance and typed decoding. These changes
+include breaking API and configuration behavior changes from v0.8.0; review the
+migration guidance below before upgrading.
+
+## Changes
+
+- Extend imports with named-file and directory lists, directory filename patterns,
+  exclusions, recursion and depth controls, and explicit hidden-file and symlink
+  discovery controls. Add `ImportDefaults` to ordinary and layered options, with
+  authored declarations taking precedence over application defaults. Imports are
+  optional by default. `SourceInfo.ImportSelections` exposes completed optional
+  declarations that selected no sources. See the
+  [import contract](../config.md#explicit-imports) and
+  [consumer guidance](../consumers/README.md#import-defaults-and-selection-inspection).
+- Use shared dependency-ready ordering for import composition and sibling
+  inheritance. Dependencies complete before dependents, with deterministic
+  selection among currently eligible contributions. Source acquisition and
+  callback order remain separate from assembly order. See the
+  [ordering decision](../adr/0015-shared-dependency-ready-ordering.md).
+- Add root `configkit.sequences` declarations for collection identity and
+  `replace`, `append`, or `upsert` operations, including in selected overlays.
+  Strict peers combine distinct identities and reject duplicates; precedence
+  and inheritance apply the destination's collection operation. Upsert replaces
+  a whole matching record at its retained position. Identity supports compound
+  field sets and scalar strings, numbers, booleans, and null. See the
+  [collection contract](../config.md#strict-document-composition).
+- Add `Definition.SequenceIdentities`, exact `SequenceIdentityAt` registrations,
+  and dynamic `SequenceIdentityMatching` selectors. Application registrations
+  govern structural collection operations and check existing matching final
+  typed sequences, including values from defaults, CLI assignments, and
+  application resolution. YAML-only declarations govern structural operations
+  without adding that final-result check.
+- Support record inheritance within an identified sequence using an `extends`
+  mapping containing the parent's complete identity. The child retains its own
+  identity, relationships use surviving assembled records, and output sequence
+  order is preserved. See [sibling inheritance](../config.md#sibling-inheritance)
+  and the maintained [sequence catalog](../consumers/README.md#identified-prompt-sequences).
+- Apply explicit CLI overrides to the decoded configuration before application
+  resolution. Mappings retain omitted fields and their presence metadata;
+  sequences replace whole lists independently of collection operations. See the
+  [CLI contract](../config.md#explicit-cli-overrides).
+- Correct native import alias and contained-symlink handling, source-version
+  path projection, and provenance/history through collection movement,
+  replacement, inheritance, and CLI assignment. Reduce repeated scans,
+  accumulated policy copying, and sparse-projection storage during construction.
+
+## Compatibility and upgrade
+
+This pre-v1 minor release intentionally changes the v0.8.0 contracts:
+
+1. **Migrate import requiredness.** The YAML `optional` field is removed and is
+   rejected. Replace `optional: true` with `required: false`; omission is equivalent
+   when the application does not default imports to required. Replace
+   `optional: false` with `required: true`. Imports that previously relied on
+   implicit requiredness now need `required: true`, or an application
+   `ImportDefaults.Required` default set to true. Review discovery filters:
+   `follow` and `hidden` default to true, and directory searches select all
+   filenames unless a pattern is supplied.
+2. **Replace sequence registrations.** `SequenceComposition` and
+   `Definition.SequenceCompositions` are removed without compatibility aliases.
+   For a previous registration at `prompts` using `id`, use:
+
+   ```go
+   rules.SequenceIdentities = []configkit.SequenceIdentity{
+       configkit.SequenceIdentityAt(configkit.Keys("prompts"), "id"),
+   }
+   ```
+
+   These registrations now also enforce identity in final typed sequences. Fix
+   missing or duplicate identities introduced by defaults, CLI assignments, or
+   application resolution. Registration does not require a collection to exist
+   or determine its allowed shape; schema and application validation retain
+   those responsibilities.
+3. **Review collection precedence and ordering.** An identified collection now
+   defaults to upsert across layers and inheritance when no explicit mode
+   applies, rather than unconditional whole-sequence replacement. Declare
+   `mode: replace` at the relevant destination where replacement is intended.
+   With append or upsert, `[]` contributes no records and does not clear the
+   collection; null is invalid. Use `mode: replace` with `[]` to clear it.
+   An explicit mode persists at its destination until changed; a parent's mode
+   does not transfer to a different inheriting destination. Unidentified
+   sequences retain strict peer conflicts and whole-value precedence
+   replacement. Dependency-ready assembly can change sequence positions and
+   diagnostic or history order compared with the former traversal order.
+4. **Review CLI recovery and inheritance assumptions.** CLI overrides can no
+   longer repair values that fail earlier decoding, bypass source or inheritance
+   errors, or add or cancel inheritance relationships. Supply structural
+   directives in source configuration. Application resolution still receives
+   explicit CLI values and may record subsequent normalization or derivation.
+5. **Update affected Go literals and diagnostic handling.** Use keyed literals
+   for expanded option and source-information structs. Collection validation adds
+   `CodeSequenceInvalid` (`sequence.invalid`) and `CodeSequenceConflict`
+   (`sequence.conflict`); update diagnostic handling where applicable.
+
+Select this version and rebuild:
+
+```sh
+go get gitea.maximumdirect.net/eric/ConfigKit@v0.9.0
+```
+
+The consumer minimum remains Go 1.26.0. The YAML dependency remains
+`go.yaml.in/yaml/v4 v4.0.0-rc.6`, and the maintainer tool dependency remains
+ReleaseKit v0.4.1. Linux amd64 and arm64 remain release-validated targets;
+macOS remains best-effort. Publication follows the existing
+[release procedure](../release.md).
+
+[COPYRIGHT](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.9.0/COPYRIGHT) | [LICENSE](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.9.0/LICENSE) | [ATTRIBUTION](https://gitea.maximumdirect.net/eric/ConfigKit/src/tag/v0.9.0/docs/oss/attribution.md)

docs/roadmap/complexity.md

@@ -0,0 +1,222 @@
+# Internal Complexity Refactoring Roadmap
+
+Status: proposed target state. This roadmap defines a behavior-preserving
+refactor; a later implementation plan will define stages and exact private
+signatures and file names.
+
+## Purpose
+
+Make ConfigKit's import, inheritance, and projection implementation easier to
+understand, review, and change while preserving its public APIs and configuration
+behavior. Concentrate on functions that coordinate several responsibilities and
+carry substantial shared state.
+
+The target is clearer responsibility and ownership. Adding a few well-named
+helpers, private records, or focused files can serve that target even when total
+line count increases. Complexity measurements help locate candidates; they do
+not establish function-size limits, score thresholds, or release gates.
+
+The [architecture policy](../policy/architecture.md) owns package and ownership
+constraints. The [configuration contract](../config.md) and exported Go comments
+remain authoritative for consumer behavior.
+
+## Current Baseline
+
+Reviewed baseline: `7a83704f43ef9870db33661231cdff5d6ee502f7`.
+
+The root facade delegates to a cohesive private engine, supported by the ordered
+document representation and YAML adapter. Most functions are small. The
+complexity audit identified these concentrated maintenance costs:
+
+| Area | Current implementation | Required improvement |
+| --- | --- | --- |
+| Imports | `imports.go` spans acquisition, item-local composition, and evidence projection. Private loading variants pass long positional argument lists. Source admission and directory selection contain substantial mixed control flow. | Give import entry points explicit, cohesive inputs and separate the responsibilities of acquisition, scope assembly, and evidence projection. |
+| Inheritance | `applyInheritanceScopeTemplates` coordinates payload preparation, parent combination, policy ownership, origins, history, and accounting in one executor. | Keep one readable executor with focused operations and explicit state handoffs. |
+| Projection | `valueOperation.project` combines type dispatch with struct flattening, map and sequence traversal, scalar conversion, sensitivity, and accounting. | Retain clear dispatch while moving substantial value-kind handling into focused helpers. |
+
+The implemented inventory belongs to the
+[component overview](../internal/overview.md). Existing import flow and scheduling
+are described in [import internals](../internal/imports.md).
+
+## Target Architecture
+
+The refactor stays within `internal/engine`. The root facade, `internal/document`,
+and `internal/yaml` retain their existing responsibilities and dependency
+direction. Focused files and ordinary private functions express the new internal
+organization. Package extraction is outside this roadmap's selected design.
+
+`executeLoadRequest` remains the visible coordinator of the shared load lifecycle.
+Its phase order should remain easy to follow. Helpers expose meaningful work and
+results rather than distributing that order across a generic execution framework.
+
+Existing shared mechanisms remain shared: recursive mapping combination,
+identified-sequence operations, dependency-ready scheduling, schema descriptors,
+and projection/accounting state. New helper boundaries make their ownership and
+use clearer without creating parallel implementations.
+
+### Imports: Cohesive Inputs And Scope Ownership
+
+Import loading has a clear private entry surface using named request/context
+fields for related inputs. Reuse the existing load-request, acquisition-scope,
+and traversal models where they fit. Consolidate forwarding variants whose only
+purpose is passing another optional positional argument through the chain.
+Retain convenience helpers when they express a useful, distinct operation.
+
+Keep these state lifetimes identifiable:
+
+- Load-wide state: accounting, shared inclusion/repetition information,
+  namespaces, and source-version processing.
+- Acquisition requests: source and filesystem context, placement, declarations,
+  applicable policy, and the relevant assembly handoff.
+- Composition scopes: peer contributions, item-local helpers, record ownership,
+  and pending declarations.
+- Evidence: physical source records, effective destinations, origins, and retained
+  history projections.
+
+Group acquisition, pending-item assembly, and evidence projection in focused
+files. A caller should be able to identify which operation acquires resources,
+which composes already acquired content, and which projects retained evidence.
+Shared mutable state has a visible owner; a request record need not duplicate
+state already held by that owner.
+
+Within dense admission, directory-selection, and declaration-parsing routines,
+extract coherent operations where that reduces nested, mixed responsibilities.
+Preserve the existing selection algorithms and host/native filesystem behavior.
+Resource ownership and closure remain explicit across success and failure paths.
+
+The resulting flow preserves the distinction among acquisition order, strict
+scope scheduling, and precedence. Completing a helper scope before placing its
+item remains part of the same import flow. Ordinary and layered loading continue
+to share the applicable mechanisms.
+
+### Inheritance: One Executor With Explicit Phases
+
+Keep the mapping and identified-sequence adapters and their shared template
+executor. The executor coordinates focused operations for:
+
+- Preparing child payload, directives, and destination-local state.
+- Preparing the resolved parent payload and applicable inherited policy.
+- Combining values through the existing mapping and sequence mechanisms.
+- Producing policy, origin, replacement, and replay evidence from that combination.
+- Accounting for expansion and retained history under the existing budgets.
+
+These are responsibility boundaries, not a required helper count or a new
+scheduler. Small private result records are appropriate when related outputs
+otherwise travel through long argument lists or implicit mutations.
+
+Authored templates, resolved values, scoped policy, and inspection evidence remain
+distinguishable. Immutable borrowed inputs and owned mutable results have clear
+lifetimes. Nested instructions remain available for destination-local evaluation.
+For identified-record inheritance, the child's own identity fields and origins
+remain intact; the parent's identity fields are excluded from inherited payload
+and its history, as the current contract requires.
+
+One sequence-operation result continues to drive value construction, record
+ownership, origins, and historical position projection. Helpers consume that
+evidence directly. Scheduling remains dependency-ready, enclosing relationships
+resolve before nested ones, and assembled sequence order remains unchanged.
+
+### Projection: Explicit Value-Kind Handlers
+
+Keep `projectConfiguration` as the schema-checked entry and `valueOperation` as
+the owner of per-operation traversal and accounting state. The central dispatch
+clearly selects the appropriate handling for pointers, dynamic values, structs,
+maps, sequences, and scalars.
+
+Substantial struct, map, and sequence work lives in focused handlers. Struct
+projection retains declaration order, inline flattening, collision diagnostics,
+and sensitivity propagation. Map projection retains deterministic key ordering.
+Scalar conversion retains the existing number, duration, text-codec, and secret
+reference representations.
+
+Depth and node accounting retain their existing meaning, including flattened
+containers. Cycle tracking stays active through recursive child traversal and
+is balanced on error paths as well as success. Passing state through a helper
+does not introduce another full-tree projection or an unnecessary ownership copy.
+
+Cloning and source-value construction remain distinct operations with their
+existing semantics. Reuse small helpers when the semantics coincide; keep the
+projection refactor centered on making the existing traversal readable.
+
+## Behavior And Scope Preservation
+
+The implementation preserves:
+
+- Root-owned public types, signatures, supported import paths, and facade boundaries.
+- Supported source forms, opt-ins, import controls, placement, acquisition and
+  composition ordering, and source/version evidence.
+- Strict peer composition, precedence operations, identity agreement and lifetime,
+  record ownership, and destination-local inheritance.
+- The load lifecycle, including typed defaults, post-decode CLI assignment,
+  recorded application resolution, and final validation.
+- Explicit presence, provenance, history, sensitivity, resource contexts, and
+  detached publication/query results.
+- Established diagnostic codes, semantic paths, source coordinates, ordering,
+  resource lifetime, and existing limit behavior.
+
+The owning contracts define the extent of these obligations. Incidental private
+call sequences, exact helper names, and allocation counts do not acquire new
+guarantees through this roadmap. The work adds no consumer options, configuration
+syntax, dependencies, or complexity-based gates.
+
+## Relationship To Remediation And Other Work
+
+The completed remediation record at `ea46001:docs/roadmap/remediation.md`
+documents the identified correctness and algorithmic efficiency findings.
+Several overlap these files, particularly item-scope application matching and
+inheritance policy localization.
+
+Use the documented contract and completed remediation as the behavioral baseline.
+Keep corrective changes reviewable under their findings, and retain their
+regressions through this refactor. The later implementation plan should coordinate
+overlapping work and select its starting revision rather than duplicating the
+remediation plan here. These structural changes do not close a finding merely
+because its function moved or became smaller.
+
+[Configuration discovery](../config.md#configuration-discovery) is implemented.
+Import cleanup should preserve its source-acquisition boundary and behavior as
+part of this refactor.
+
+## Work Needed And Validation
+
+Implementation needs to consolidate import inputs and adapters, separate import
+responsibilities, extract inheritance operations with explicit outputs, and
+decompose projection handling. Remove superseded private plumbing as its callers
+migrate. Review the resulting call flow for repeated traversals, policy scans,
+copies, or hidden state transitions introduced by extraction.
+
+Reuse the existing behavioral suites under the
+[development guide](../development.md) and [testing policy](../policy/testing.md):
+
+- Imports: selection, scheduling, source/version evidence, placement, helper scopes,
+  ordinary/layered equivalence, filesystem failures, and resource lifetime.
+- Inheritance: mapping and record relationships, nested destination resolution,
+  cancellation and replacement, policy ownership, history, sensitivity, and
+  independent loads.
+- Projection: schema/decoding agreement, inline fields, text codecs, nil/empty
+  values, cycles and budgets, secrets, and detached results.
+
+Add focused regressions only where a consequential handoff risk lacks coverage.
+Tests should continue to describe behavior as private functions and files move.
+Use the existing everyday check and applicable ownership race checks during
+implementation. Complexity measurements can inform review; acceptance does not
+depend on numerical scores or a new benchmark campaign.
+
+Update the component overview and import internals to describe the implemented
+ownership and file responsibilities when the refactor lands. Update contributor
+navigation and test-owner references where moves affect them. Public behavior
+continues to be defined by its current canonical owners.
+
+## Completion Criteria
+
+- Import callers pass cohesive named inputs, with clearly owned load-wide and
+  scope-local state and fewer redundant forwarding variants.
+- Import acquisition, item assembly, and evidence projection are easy to locate
+  and follow across focused private files.
+- Inheritance orchestration exposes value, policy, evidence, and accounting work
+  without requiring readers to reconstruct their interaction from one large body.
+- Projection dispatch and substantial value-kind handlers have clear boundaries
+  and share the original operation state correctly.
+- Existing APIs and contracted behavior, including completed remediation, remain
+  covered by the relevant behavioral and ownership checks.
+- Internal documentation matches the resulting implementation.

docs/roadmap/deferred.md

@@ -1,28 +0,0 @@
-# Deferred Scope
-
-This document owns intentionally excluded features, not a committed delivery plan.
-The [architecture policy](../policy/architecture.md) governs changes to these
-boundaries. Implemented behavior belongs in the [configuration contract](../config.md)
-and consumer adoption in the [consumer guide](../consumers/README.md).
-
-## Explicit non-goals and deferred scope
-
-General environment-variable configuration overlays are not supported. Typed secret
-references and explicit directory bootstrap are the environment convention. Literal
-credential configuration and implicit secret-directory discovery are unsupported.
-
-The initial release deliberately excludes:
-
-- automatic `conf.d` discovery;
-- remote imports, arbitrary providers, and additional configuration formats;
-- custom merge strategies, sequence merging, reset operators, and overlay inheritance;
-- parser-specific or custom structural-decoding extension APIs;
-- generic dynamic-subtree conversion and module-registry APIs;
-- automatic schema migrations;
-- hot reload, runtime resource replacement, and remote resource validation;
-- a bundled CLI framework or application commands; and
-- configuration diffs and fingerprints.
-
-Applications may build their own validate, effective-value, source, bootstrap, and
-explanation commands around the library. Broadening these boundaries requires
-concrete consumer evidence, compatibility review, and an explicit design change.

docs/roadmap/future.md

@@ -0,0 +1,85 @@
+# Potential Future Features
+
+This document lists potential enhancements for consideration in future ConfigKit
+releases. Entries are not accepted contracts, implementation plans, or release
+commitments. Adopting a candidate requires an explicit design decision and a
+separate plan. Significant architectural exclusions and their rationale belong
+in ADRs; this document does not maintain a list of rejected proposals.
+
+## 1. Recursive body merging for identified records
+
+Status: deferred. The implemented
+[collection policy](../config.md#strict-document-composition) uses `upsert` to
+replace a complete matched record. Recursive merging of fields inside matching
+records remains a separate candidate and would revisit the whole-record update
+boundary selected by [ADR 0017](../adr/0017-collection-sequence-policy.md).
+
+Consider this only in response to a concrete consumer need. A proposal would need
+to define conflicts for overlapping body fields, removal of omitted fields,
+presence and ordering, and how provenance, history, sensitivity, and resource
+context follow partially retained records. Any change requires a new decision and
+implementation plan; this entry does not alter current upsert behavior.
+
+## 2. Required version declarations for selected sources
+
+Status: deferred. PromptKit requested a way to require version declarations on
+a selected subset of source files while permitting other fragments to omit them.
+
+### Motivation and proposed behavior
+
+PromptKit could require each collection's root file (for example,
+`collection.yml` or `meta.yml`, with naming still undecided) to declare an
+accepted specification version. Other files would use the existing
+[check-when-present behavior](../config.md#shared-source-version-checks).
+This would enforce a rule that otherwise remains a documentation convention.
+
+All declarations would use the same application-owned `Definition.Version`
+path and acceptance policy. The proposal concerns where declarations are
+required; it does not introduce independently versioned collections or subtrees.
+A root declaration would not prove that headerless descendants declare a
+compatible version or replace final configuration validation.
+
+### Questions to resolve before implementation
+
+- **Selection API:** should callers mark explicit inputs, select sources by
+  path or predicate, or annotate imports? An input-level requirement is simpler,
+  but cannot by itself select a root reached only through an import.
+- **Scope:** does a requirement apply only to the selected document or also to
+  its imports? Applying it only to that document best fits PromptKit's request;
+  imported fragments could still declare versions checked by the shared policy.
+- **Mode interaction:** how should selection interact with disabled source
+  checks? Require an enabled mode, or activate checking for selected sources?
+  Selection would strengthen check-when-present behavior and add no requirement
+  beyond the load-wide required mode.
+- **Source handling and evidence:** how should selection work across file,
+  reader, byte, and mapping inputs, glob matches, and repeated imports? Define
+  behavior for absent optional inputs and preserve source-local diagnostics,
+  inspection evidence, and existing sensitivity handling.
+
+## 3. Performance experiments
+
+Status: deferred pending evidence. The completed performance audit identified
+four internal optimization candidates for separate investigation:
+
+- Branch-local explanation replay instead of the current whole-tree replay.
+- Redesigning the private metadata-copy handoff while preserving detached public
+  records.
+- Caching schema descriptors across loads.
+- Indexing complex contributor-trace membership while preserving its equality
+  rules and compact linked traces.
+
+These are experiments, not committed implementation work or promised speedups.
+Reconsider them with evidence that the benefit justifies the ownership,
+retained-memory, or equivalence risks. The completed audit and implementation
+evidence are preserved in Git history at `8e91a2b` under `docs/roadmap/`.
+
+### Questions to resolve before implementation
+
+- Which representative workloads show enough remaining cost to justify each
+  optimization, and what measurements would establish a useful improvement?
+- Can narrower replay and membership indexes preserve explanation results,
+  ordering, provenance, and sensitivity behavior?
+- Can metadata handoff changes preserve detached public records and ownership
+  across loads without introducing aliasing?
+- What cache lifetime and concurrency design would make schema reuse worthwhile
+  without excessive retained memory?

example_test.go

@@ -19,6 +19,28 @@ func ExampleLoad() {
 	// Output: {true 3} <nil>
 }
 
+func ExampleLoad_sequenceDeclaration() {
+	type Item struct {
+		ID string `yaml:"id"`
+	}
+	type Config struct {
+		Items []Item `yaml:"items"`
+	}
+	result, err := configkit.Load[Config](configkit.Bytes("catalog.yml", []byte(`configkit:
+  sequences:
+    - destination: [items]
+      key: id
+items:
+  - id: prompt
+`)))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println(result.Config.Items[0].ID)
+	// Output: prompt
+}
+
 func ExampleNoSource() {
 	type Config struct {
 		Workers int `yaml:"workers"`
@@ -30,6 +52,32 @@ func ExampleNoSource() {
 	// Output: 4 0 <nil>
 }
 
+func ExampleDiff() {
+	type Config struct {
+		Workers int `yaml:"workers"`
+	}
+	before, err := configkit.Load[Config](configkit.Mapping("before", map[string]any{"workers": 2}))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	after, err := configkit.Load[Config](configkit.Mapping("after", map[string]any{"workers": 4}))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	differences, err := configkit.Diff(before, after)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	for _, difference := range differences {
+		fmt.Printf("%s: %s -> %s\n", difference.Path.String(),
+			strings.TrimSpace(difference.Left.YAML), strings.TrimSpace(difference.Right.YAML))
+	}
+	// Output: /workers: 2 -> 4
+}
+
 func ExampleValidation_Error() {
 	type Config struct {
 		First  string `yaml:"first"`
@@ -128,8 +176,15 @@ func ExampleOverride() {
 		})
 	}
 	result, err := configkit.Load(configkit.NoSource(), configkit.Options[Config]{
-		Definition: configkit.Definition[Config]{Defaults: func() Config { return Config{Workers: 4} }},
-		Overrides:  overrides,
+		Definition: configkit.Definition[Config]{
+			Defaults: func() Config { return Config{Workers: 4} },
+			Resolve: func(configuration *Config, resolution *configkit.Resolution) error {
+				configkit.Default(resolution, configkit.Keys("workers"), &configuration.Workers, 100,
+					"preserve an explicitly supplied worker count")
+				return nil
+			},
+		},
+		Overrides: overrides,
 	})
 	fmt.Println(result.Config.Workers, result.Sources()[0].Label, err)
 	// Output: 0 --workers <nil>

examples/consumers/consumers_test.go

@@ -52,6 +52,22 @@ func Example_seriatim() {
 	// Output: visitor true the event occurred <nil> <nil>
 }
 
+func Example_inheritedPresets() {
+	result, err := consumers.LoadPresets(configkit.File(fixture("inheritance", "presets.yml")))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	path := configkit.Keys("presets", "custom", "enabled")
+	info, _ := result.Metadata().Lookup(path)
+	custom := result.Config.Presets["custom"]
+	fmt.Println(custom.Enabled, result.Metadata().IsExplicit(path), custom.Settings["secondary"]["width"])
+	fmt.Println(info.Origin.Locations[0].SourceID, info.Origin.Inheritance[0].From)
+	// Output:
+	// false true 20
+	// source-1 /presets/base/enabled
+}
+
 func Example_weatherStartup() {
 	const blockedName = "CONFIGKIT_WEATHER_EXAMPLE_BLOCKED"
 	const tokenName = "CONFIGKIT_WEATHER_EXAMPLE_TOKEN"

examples/consumers/destinations.go

@@ -0,0 +1,154 @@
+package consumers
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"path"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+// CollectionBundleConfig is a representative application-owned collection
+// shape. Collection and prompt version labels remain ordinary domain fields.
+type CollectionBundleConfig struct {
+	Version     string                          `yaml:"version"`
+	Collections map[string]CollectionDefinition `yaml:"collections"`
+}
+
+type CollectionDefinition struct {
+	Name        string                       `yaml:"name"`
+	Version     string                       `yaml:"version"`
+	Description string                       `yaml:"description"`
+	Prompts     map[string]CollectionPrompt  `yaml:"prompts"`
+	Profiles    map[string]CollectionProfile `yaml:"profiles"`
+}
+
+type CollectionPrompt struct {
+	Version        string              `yaml:"version"`
+	DefaultProfile string              `yaml:"default_profile"`
+	ContentFile    string              `yaml:"content_file"`
+	ResourceText   string              `yaml:"resource_text"`
+	Messages       []CollectionMessage `yaml:"messages"`
+}
+
+type CollectionMessage struct {
+	Role    string `yaml:"role"`
+	Content string `yaml:"content"`
+}
+
+type CollectionProfile struct {
+	Format      string  `yaml:"format"`
+	Temperature float64 `yaml:"temperature"`
+}
+
+// LoadCollectionBundle demonstrates one layered collection load. Its main
+// document owns the application schema version; the mounted entry declares
+// relative destinations for collection metadata, prompt/profile peers, and
+// their nested imports. The operator version override remains a separate tier.
+func LoadCollectionBundle() (*configkit.Result[CollectionBundleConfig], error) {
+	files, err := fs.Sub(bundledFiles, "testdata/collection-bundle")
+	if err != nil {
+		return nil, err
+	}
+	bundle := configkit.NewFilesystem("collection bundle", files)
+	collectionDestination := configkit.Keys("collections", "weatherreporter")
+	promptDestination := collectionDestination.Key("prompts")
+	return configkit.LoadLayered(
+		configkit.Input{Source: configkit.Bytes("application main", []byte("version: 1\n"))},
+		configkit.LayeredOptions[CollectionBundleConfig]{
+			Definition: configkit.Definition[CollectionBundleConfig]{
+				Version: &configkit.VersionRule{Path: configkit.Keys("version"), Check: func(version configkit.Version, _ *configkit.Validation) error {
+					if !version.Present || version.Text != "1" {
+						return errors.New("unsupported application schema version")
+					}
+					return nil
+				}},
+				Resolve:  resolveCollectionResources,
+				Validate: validateCollectionBundle,
+			},
+			Underlays: []configkit.Underlay{
+				{Inputs: []configkit.Input{{
+					Source: bundle.File("collections/weather/collection.yml"), Imports: true, Destination: collectionDestination,
+				}}},
+				{Inputs: []configkit.Input{{
+					Source: bundle.File("operators/weather-prompt-version.yml"), Destination: promptDestination,
+				}}},
+			},
+		},
+	)
+}
+
+func resolveCollectionResources(configuration *CollectionBundleConfig, resolution *configkit.Resolution) error {
+	for collectionID, collection := range configuration.Collections {
+		for promptID, prompt := range collection.Prompts {
+			if prompt.ContentFile == "" {
+				continue
+			}
+			contentPath := configkit.Keys("collections", collectionID, "prompts", promptID, "content_file")
+			info, found := resolution.InputInfo(contentPath)
+			if !found || len(info.Origin.Locations) != 1 {
+				return fmt.Errorf("prompt resource has no single declaring source")
+			}
+			resourceSource, found := resolution.Source(info.Origin.Locations[0].SourceID)
+			if !found {
+				return fmt.Errorf("prompt resource source is unavailable")
+			}
+			context, found := resolution.SourceContext(resourceSource.ID)
+			if !found {
+				return fmt.Errorf("prompt resource context is unavailable")
+			}
+			data, err := fs.ReadFile(context.FS, path.Join(context.BaseDir, prompt.ContentFile))
+			if err != nil {
+				return fmt.Errorf("read prompt resource: %w", err)
+			}
+			prompt.ResourceText = string(data)
+			collection.Prompts[promptID] = prompt
+			resolution.Record(
+				configkit.Keys("collections", collectionID, "prompts", promptID, "resource_text"),
+				configkit.ChangeNormalization, "read source-relative prompt content", contentPath,
+			)
+		}
+		configuration.Collections[collectionID] = collection
+	}
+	return nil
+}
+
+func validateCollectionBundle(configuration *CollectionBundleConfig, validation *configkit.Validation) {
+	for collectionID, collection := range configuration.Collections {
+		for promptID, prompt := range collection.Prompts {
+			if prompt.DefaultProfile == "" {
+				continue
+			}
+			if _, found := collection.Profiles[prompt.DefaultProfile]; !found {
+				validation.Error(configkit.Keys("collections", collectionID, "prompts", promptID, "default_profile"), "must name a profile in this collection")
+			}
+		}
+	}
+}
+
+// ReadCollectionPromptContent follows the effective content field's physical
+// source, including when it was inherited from a peer prompt.
+func ReadCollectionPromptContent(result *configkit.Result[CollectionBundleConfig], collectionID, promptID string) (string, error) {
+	if result == nil {
+		return "", errors.New("collection result is nil")
+	}
+	contentPath := configkit.Keys("collections", collectionID, "prompts", promptID, "content_file")
+	info, found := result.Metadata().Lookup(contentPath)
+	if !found || len(info.Origin.Locations) != 1 {
+		return "", errors.New("prompt resource has no single declaring source")
+	}
+	context, found := result.SourceContext(info.Origin.Locations[0].SourceID)
+	if !found {
+		return "", errors.New("prompt resource context is unavailable")
+	}
+	prompt, found := result.Config.Collections[collectionID].Prompts[promptID]
+	if !found {
+		return "", errors.New("prompt is unavailable")
+	}
+	data, err := fs.ReadFile(context.FS, path.Join(context.BaseDir, prompt.ContentFile))
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}

examples/consumers/destinations_test.go

@@ -0,0 +1,137 @@
+package consumers_test
+
+import (
+	"errors"
+	"fmt"
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+	"gitea.maximumdirect.net/eric/ConfigKit/examples/consumers"
+)
+
+func Example_inputDestination() {
+	mounted, err := configkit.LoadLayered[map[string]any](configkit.Input{
+		Source: configkit.Mapping("weather prompt", map[string]any{
+			"summarize.alerts": map[string]any{"version": "1"},
+		}),
+		Destination: configkit.Keys("collections", "weather.reporter", "prompts"),
+	})
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	root, err := configkit.LoadLayered[map[string]any](configkit.Input{
+		Source: configkit.Bytes("standalone", []byte("name: standalone\n")),
+	})
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	_, found := mounted.Config["collections"]
+	fmt.Println(found, root.Config["name"])
+	// Output: true standalone
+}
+
+func TestCollectionBundleAssemblesMountedPeersAndResources(t *testing.T) {
+	result, err := consumers.LoadCollectionBundle()
+	if err != nil {
+		t.Fatalf("LoadCollectionBundle: %v", err)
+	}
+	collection := result.Config.Collections["weatherreporter"]
+	if result.Config.Version != "1" || collection.Name != "Weather Reporter" || collection.Version != "2.4.0" {
+		t.Fatalf("main and collection versions = %q, %#v", result.Config.Version, collection)
+	}
+	brief := collection.Prompts["brief"]
+	custom := collection.Prompts["custom"]
+	if brief.Version != "2" || brief.DefaultProfile != "compact" || brief.ContentFile != "welcome.txt" || len(brief.Messages) != 1 {
+		t.Fatalf("version-only override replaced lower prompt fields: %#v", brief)
+	}
+	if custom.Version != "2" || custom.DefaultProfile != "weather" || custom.ContentFile != brief.ContentFile ||
+		len(custom.Messages) != 1 || custom.ResourceText != "Welcome to the weather collection.\n" {
+		t.Fatalf("inherited prompt = %#v", custom)
+	}
+	weatherProfile := collection.Profiles["weather"]
+	if weatherProfile.Format != "text" || weatherProfile.Temperature != 0.4 {
+		t.Fatalf("inherited profile = %#v", weatherProfile)
+	}
+	resource, err := consumers.ReadCollectionPromptContent(result, "weatherreporter", "custom")
+	if err != nil || resource != custom.ResourceText {
+		t.Fatalf("inherited prompt resource = %q, %v", resource, err)
+	}
+
+	versionInfo, ok := result.Metadata().Lookup(configkit.Keys("version"))
+	if !ok || !versionInfo.Explicit || versionInfo.Origin.Layer != configkit.LayerBase || len(versionInfo.Origin.Locations) != 1 {
+		t.Fatalf("main-owned version metadata = %#v, %v", versionInfo, ok)
+	}
+	collectionVersionPath := configkit.Keys("collections", "weatherreporter", "version")
+	collectionVersion, ok := result.Metadata().Lookup(collectionVersionPath)
+	if !ok || !collectionVersion.Explicit || collectionVersion.Origin.Layer != configkit.LayerUnderlay || len(collectionVersion.Origin.Locations) != 1 {
+		t.Fatalf("ordinary collection version metadata = %#v, %v", collectionVersion, ok)
+	}
+	var metadataSource configkit.SourceInfo
+	var collectionEntrySource configkit.SourceInfo
+	var versionSource configkit.SourceInfo
+	var parentPromptSource configkit.SourceInfo
+	var promptIndexSource configkit.SourceInfo
+	var profileIndexSource configkit.SourceInfo
+	var promptVersionSource configkit.SourceInfo
+	for _, source := range result.Sources() {
+		switch source.Path {
+		case "collections/weather/collection.yml":
+			collectionEntrySource = source
+		case "collections/weather/metadata.yml":
+			metadataSource = source
+		case "collections/weather/version.yml":
+			versionSource = source
+		case "collections/weather/prompts/index.yml":
+			promptIndexSource = source
+		case "collections/weather/prompts/brief.yml":
+			parentPromptSource = source
+		case "collections/weather/profiles/index.yml":
+			profileIndexSource = source
+		case "operators/weather-prompt-version.yml":
+			promptVersionSource = source
+		}
+	}
+	collectionVersionLocation := collectionVersion.Origin.Locations[0]
+	if collectionEntrySource.ID != "source-2" || collectionEntrySource.Destination.String() != "/collections/weatherreporter" ||
+		metadataSource.ID == "" || metadataSource.Destination.String() != "/collections/weatherreporter" ||
+		metadataSource.ImportedFrom == nil || metadataSource.ImportedFrom.SourceID != collectionEntrySource.ID ||
+		versionSource.ID == "" || collectionVersionLocation.SourceID != versionSource.ID || versionSource.Destination.String() != "/collections/weatherreporter" ||
+		versionSource.ImportedFrom == nil || versionSource.ImportedFrom.SourceID != metadataSource.ID || collectionVersionLocation.Line != 1 {
+		t.Fatalf("nested collection version provenance = entry %#v, metadata %#v, version %#v, location %#v", collectionEntrySource, metadataSource, versionSource, collectionVersionLocation)
+	}
+	if promptIndexSource.ID == "" || promptIndexSource.Destination.String() != "/collections/weatherreporter/prompts" ||
+		promptIndexSource.ImportedFrom == nil || promptIndexSource.ImportedFrom.SourceID != collectionEntrySource.ID ||
+		profileIndexSource.ID == "" || profileIndexSource.Destination.String() != "/collections/weatherreporter/profiles" ||
+		profileIndexSource.ImportedFrom == nil || profileIndexSource.ImportedFrom.SourceID != collectionEntrySource.ID {
+		t.Fatalf("nested prompt/profile placement = prompt %#v profile %#v", promptIndexSource, profileIndexSource)
+	}
+	if promptVersionSource.ID == "" || promptVersionSource.Destination.String() != "/collections/weatherreporter/prompts" || promptVersionSource.UnderlayIndex != 2 {
+		t.Fatalf("prompt version source = %#v", promptVersionSource)
+	}
+	contentPath := configkit.Keys("collections", "weatherreporter", "prompts", "custom", "content_file")
+	contentInfo, ok := result.Metadata().Lookup(contentPath)
+	if !ok || !contentInfo.Explicit || len(contentInfo.Origin.Inheritance) != 1 || len(contentInfo.Origin.Locations) != 1 {
+		t.Fatalf("inherited content field metadata = %#v, %v", contentInfo, ok)
+	}
+	contentLocation := contentInfo.Origin.Locations[0]
+	if parentPromptSource.ID == "" || contentLocation.SourceID != parentPromptSource.ID || contentLocation.Line != 4 ||
+		parentPromptSource.Destination.String() != "/collections/weatherreporter/prompts" {
+		t.Fatalf("inherited resource source coordinates = %#v, source %#v", contentLocation, parentPromptSource)
+	}
+}
+
+func TestCollectionPeerPromptConflictsRemainStrict(t *testing.T) {
+	destination := configkit.Keys("collections", "weatherreporter", "prompts")
+	_, err := configkit.LoadLayered[map[string]any](configkit.Input{Source: configkit.NoSource()}, configkit.LayeredOptions[map[string]any]{
+		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{
+			{Source: configkit.Bytes("peer-a", []byte("brief: {version: '1'}\n")), Destination: destination},
+			{Source: configkit.Bytes("peer-b", []byte("brief: {version: '1'}\n")), Destination: destination},
+		}}},
+	})
+	var loadError *configkit.LoadError
+	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) == 0 || loadError.Diagnostics()[0].Code != configkit.CodeComposeConflict {
+		t.Fatalf("duplicate peer prompt error = %v", err)
+	}
+}

examples/consumers/diff.go

@@ -0,0 +1,136 @@
+package consumers
+
+import (
+	"fmt"
+	"strconv"
+	"strings"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+// FileComparisonConfig is a small application-owned shape for comparing
+// caller-selected configuration files.
+type FileComparisonConfig struct {
+	Name    string         `yaml:"name"`
+	Entries map[string]any `yaml:"entries"`
+}
+
+// CompareFiles loads two caller-selected files with the same application
+// definition, then formats only the safe records returned by configkit.Diff.
+func CompareFiles(leftPath, rightPath string) (string, error) {
+	options := configkit.Options[FileComparisonConfig]{
+		Definition: configkit.Definition[FileComparisonConfig]{
+			Defaults: func() FileComparisonConfig {
+				return FileComparisonConfig{Entries: map[string]any{}}
+			},
+		},
+	}
+	left, err := configkit.Load(configkit.File(leftPath), options)
+	if err != nil {
+		return "", fmt.Errorf("load left configuration: %w", err)
+	}
+	right, err := configkit.Load(configkit.File(rightPath), options)
+	if err != nil {
+		return "", fmt.Errorf("load right configuration: %w", err)
+	}
+	differences, err := configkit.Diff(left, right)
+	if err != nil {
+		return "", err
+	}
+	return FormatDifferences(differences), nil
+}
+
+// RolloutConfig models a service endpoint whose URL is derived by the
+// application resolver and whose credential reference is classified.
+type RolloutConfig struct {
+	Service RolloutService `yaml:"service"`
+}
+
+// RolloutService contains endpoint settings and a classified credential.
+type RolloutService struct {
+	Endpoint   RolloutEndpoint   `yaml:"endpoint"`
+	Credential RolloutCredential `yaml:"credential"`
+}
+
+// RolloutEndpoint is the effective destination used by the application.
+type RolloutEndpoint struct {
+	Host string `yaml:"host"`
+	Port int    `yaml:"port"`
+	URL  string `yaml:"url"`
+}
+
+// RolloutCredential holds only a typed secret reference in configuration.
+type RolloutCredential struct {
+	Token configkit.Secret `yaml:"token" configkit:"secret"`
+}
+
+// LoadRollout loads a base file, optionally with one selected configuration
+// overlay. Resolution derives the effective URL after the overlay is applied.
+func LoadRollout(basePath, overlayName string) (*configkit.Result[RolloutConfig], error) {
+	return configkit.Load(configkit.File(basePath), configkit.Options[RolloutConfig]{
+		Overlay: overlayName,
+		Definition: configkit.Definition[RolloutConfig]{
+			Resolve: resolveRollout,
+		},
+	})
+}
+
+// CompareRolloutOverlay compares the effective base configuration with that
+// same file plus one selected overlay. It presents only safe diff records.
+func CompareRolloutOverlay(basePath, overlayName string) (string, error) {
+	base, err := LoadRollout(basePath, "")
+	if err != nil {
+		return "", fmt.Errorf("load base configuration: %w", err)
+	}
+	withOverlay, err := LoadRollout(basePath, overlayName)
+	if err != nil {
+		return "", fmt.Errorf("load overlay configuration: %w", err)
+	}
+	differences, err := configkit.Diff(base, withOverlay)
+	if err != nil {
+		return "", err
+	}
+	return FormatDifferences(differences), nil
+}
+
+func resolveRollout(configuration *RolloutConfig, resolution *configkit.Resolution) error {
+	endpoint := &configuration.Service.Endpoint
+	if endpoint.Host == "" || endpoint.Port <= 0 {
+		return nil
+	}
+	url := fmt.Sprintf("https://%s:%d", endpoint.Host, endpoint.Port)
+	if endpoint.URL != url {
+		endpoint.URL = url
+		resolution.Record(configkit.Keys("service", "endpoint", "url"),
+			configkit.ChangeNormalization, "derived endpoint URL",
+			configkit.Keys("service", "endpoint", "host"),
+			configkit.Keys("service", "endpoint", "port"))
+	}
+	return nil
+}
+
+// FormatDifferences is consumer-owned presentation. It distinguishes absence
+// through Present and reports withheld changes through HiddenChanged without
+// interpreting redaction marker text.
+func FormatDifferences(differences []configkit.Difference) string {
+	if len(differences) == 0 {
+		return "No effective changes.\n"
+	}
+	var output strings.Builder
+	for _, difference := range differences {
+		fmt.Fprintf(&output, "%s: left=%s right=%s", difference.Path.String(),
+			formatSnapshot(difference.Left), formatSnapshot(difference.Right))
+		if difference.HiddenChanged {
+			output.WriteString(" hidden-change")
+		}
+		output.WriteByte('\n')
+	}
+	return output.String()
+}
+
+func formatSnapshot(snapshot configkit.ValueSnapshot) string {
+	if !snapshot.Present {
+		return "<absent>"
+	}
+	return strconv.Quote(snapshot.YAML)
+}

examples/consumers/diff_test.go

@@ -0,0 +1,187 @@
+package consumers_test
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+	"strings"
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+	"gitea.maximumdirect.net/eric/ConfigKit/examples/consumers"
+)
+
+func ExampleCompareFiles() {
+	directory, err := os.MkdirTemp("", "configkit-diff-files-")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer os.RemoveAll(directory)
+	leftPath := filepath.Join(directory, "before.yml")
+	rightPath := filepath.Join(directory, "after.yml")
+	if err := os.WriteFile(leftPath, []byte("name: before\nentries: {}\n"), 0o600); err != nil {
+		fmt.Println(err)
+		return
+	}
+	if err := os.WriteFile(rightPath, []byte("name: after\nentries:\n  added: null\n"), 0o600); err != nil {
+		fmt.Println(err)
+		return
+	}
+	output, err := consumers.CompareFiles(leftPath, rightPath)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Print(output)
+	// Output:
+	// /entries/added: left=<absent> right="null\n"
+	// /name: left="before\n" right="after\n"
+}
+
+func ExampleCompareRolloutOverlay() {
+	const baseToken = "CONFIGKIT_DIFF_EXAMPLE_BASE_TOKEN"
+	const overlayToken = "CONFIGKIT_DIFF_EXAMPLE_OVERLAY_TOKEN"
+	defer preserveEnvironment(baseToken)()
+	defer preserveEnvironment(overlayToken)()
+	_ = os.Setenv(baseToken, "disposable-example-base-credential")
+	_ = os.Setenv(overlayToken, "disposable-example-overlay-credential")
+
+	directory, err := os.MkdirTemp("", "configkit-diff-overlay-")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer os.RemoveAll(directory)
+	basePath := filepath.Join(directory, "config.yml")
+	overlayPath := filepath.Join(directory, "overlays", "canary.yml")
+	if err := os.MkdirAll(filepath.Dir(overlayPath), 0o700); err != nil {
+		fmt.Println(err)
+		return
+	}
+	base := "service:\n  endpoint:\n    host: base.example\n    port: 8443\n  credential:\n    token: " + baseToken + "\n"
+	overlay := "service:\n  endpoint:\n    host: canary.example\n  credential:\n    token: " + overlayToken + "\n"
+	if err := os.WriteFile(basePath, []byte(base), 0o600); err != nil {
+		fmt.Println(err)
+		return
+	}
+	if err := os.WriteFile(overlayPath, []byte(overlay), 0o600); err != nil {
+		fmt.Println(err)
+		return
+	}
+	output, err := consumers.CompareRolloutOverlay(basePath, "canary")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Print(output)
+	// Output:
+	// /service/credential/token: left="'[REDACTED]'\n" right="'[REDACTED]'\n" hidden-change
+	// /service/endpoint/host: left="base.example\n" right="canary.example\n"
+	// /service/endpoint/url: left="https://base.example:8443\n" right="https://canary.example:8443\n"
+}
+
+func TestCompareFilesUsesCallerSelectedSourcesAndSafePresence(t *testing.T) {
+	directory := t.TempDir()
+	leftPath := filepath.Join(directory, "before.yml")
+	rightPath := filepath.Join(directory, "after.yml")
+	writeConfiguration(t, leftPath, "name: before\nentries: {}\n")
+	writeConfiguration(t, rightPath, "name: after\nentries:\n  added: null\n")
+
+	output, err := consumers.CompareFiles(leftPath, rightPath)
+	if err != nil {
+		t.Fatal(err)
+	}
+	want := "/entries/added: left=<absent> right=\"null\\n\"\n" +
+		"/name: left=\"before\\n\" right=\"after\\n\"\n"
+	if output != want {
+		t.Fatalf("comparison output = %q, want %q", output, want)
+	}
+	if again, err := consumers.CompareFiles(leftPath, rightPath); err != nil || again != output {
+		t.Fatalf("repeat output = %q, %v", again, err)
+	}
+}
+
+func TestCompareFilesReturnsEachLoadError(t *testing.T) {
+	directory := t.TempDir()
+	leftPath := filepath.Join(directory, "before.yml")
+	rightPath := filepath.Join(directory, "after.yml")
+	writeConfiguration(t, leftPath, "name: before\n")
+	writeConfiguration(t, rightPath, "unknown: invalid\n")
+
+	output, err := consumers.CompareFiles(leftPath, rightPath)
+	if err == nil || output != "" || !strings.Contains(err.Error(), "load right configuration") {
+		t.Fatalf("right load failure = %q, %v", output, err)
+	}
+	if _, err := consumers.CompareFiles(filepath.Join(directory, "missing.yml"), rightPath); err == nil || !strings.Contains(err.Error(), "load left configuration") {
+		t.Fatalf("left load failure = %v", err)
+	}
+}
+
+func TestCompareRolloutOverlayShowsResolvedSafeChangesAndRetainsSiblings(t *testing.T) {
+	t.Setenv("CONFIGKIT_DIFF_BASE_TOKEN", "disposable-base-credential")
+	t.Setenv("CONFIGKIT_DIFF_OVERLAY_TOKEN", "disposable-overlay-credential")
+	directory := t.TempDir()
+	basePath := filepath.Join(directory, "config.yml")
+	overlayPath := filepath.Join(directory, "overlays", "canary.yml")
+	if err := os.MkdirAll(filepath.Dir(overlayPath), 0o700); err != nil {
+		t.Fatal(err)
+	}
+	writeConfiguration(t, basePath, "service:\n  endpoint:\n    host: base.example\n    port: 8443\n  credential:\n    token: CONFIGKIT_DIFF_BASE_TOKEN\n")
+	writeConfiguration(t, overlayPath, "service:\n  endpoint:\n    host: canary.example\n  credential:\n    token: CONFIGKIT_DIFF_OVERLAY_TOKEN\n")
+
+	base, err := consumers.LoadRollout(basePath, "")
+	if err != nil {
+		t.Fatal(err)
+	}
+	withOverlay, err := consumers.LoadRollout(basePath, "canary")
+	if err != nil {
+		t.Fatal(err)
+	}
+	if base.Config.Service.Endpoint.Port != 8443 || withOverlay.Config.Service.Endpoint.Port != 8443 {
+		t.Fatalf("lower-priority port was not retained: base=%#v overlay=%#v", base.Config.Service.Endpoint, withOverlay.Config.Service.Endpoint)
+	}
+	urlInfo, found := withOverlay.Metadata().Lookup(configkit.Keys("service", "endpoint", "url"))
+	if !found || urlInfo.Origin.Layer != configkit.LayerResolution || withOverlay.Config.Service.Endpoint.URL != "https://canary.example:8443" {
+		t.Fatalf("resolved endpoint = %#v, metadata=%#v, %v", withOverlay.Config.Service.Endpoint, urlInfo, found)
+	}
+
+	differences, err := configkit.Diff(base, withOverlay)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if len(differences) != 3 {
+		t.Fatalf("differences = %#v", differences)
+	}
+	wantPaths := []string{"/service/credential/token", "/service/endpoint/host", "/service/endpoint/url"}
+	for index, difference := range differences {
+		if got := difference.Path.String(); got != wantPaths[index] {
+			t.Errorf("path[%d] = %q, want %q", index, got, wantPaths[index])
+		}
+	}
+	secret := differences[0]
+	if !secret.Left.Redacted || !secret.Right.Redacted || !secret.HiddenChanged || secret.Left.YAML != "'[REDACTED]'\n" || secret.Right.YAML != "'[REDACTED]'\n" {
+		t.Fatalf("classified credential difference = %#v", secret)
+	}
+	if strings.Contains(consumers.FormatDifferences(differences), "disposable-") {
+		t.Fatal("formatted differences exposed credential contents")
+	}
+
+	output, err := consumers.CompareRolloutOverlay(basePath, "canary")
+	if err != nil || output != consumers.FormatDifferences(differences) {
+		t.Fatalf("formatted base/overlay comparison = %q, %v", output, err)
+	}
+}
+
+func TestFormatDifferencesUsesRecordMembershipForNoChange(t *testing.T) {
+	if got := consumers.FormatDifferences(nil); got != "No effective changes.\n" {
+		t.Fatalf("no-change output = %q", got)
+	}
+}
+
+func writeConfiguration(t *testing.T, filename, contents string) {
+	t.Helper()
+	if err := os.WriteFile(filename, []byte(contents), 0o600); err != nil {
+		t.Fatal(err)
+	}
+}

examples/consumers/discovery_test.go

@@ -0,0 +1,45 @@
+package consumers_test
+
+import (
+	"fmt"
+	"os"
+	"path/filepath"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+type workingDirectoryPresetConfig struct {
+	Name string `yaml:"name"`
+}
+
+func Example_workingDirectoryPreset() {
+	original, err := os.Getwd()
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer func() { _ = os.Chdir(original) }()
+	root, err := os.MkdirTemp("", "configkit-working-search-")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	defer os.RemoveAll(root)
+	if err := os.Chdir(root); err != nil {
+		fmt.Println(err)
+		return
+	}
+	if err := os.WriteFile(filepath.Join(root, "service.yml"), []byte("name: example\n"), 0o600); err != nil {
+		fmt.Println(err)
+		return
+	}
+	result, err := configkit.Load[workingDirectoryPresetConfig](
+		configkit.SearchConfig("service", configkit.WorkingDirectory()),
+	)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println(result.Config.Name, filepath.Base(result.Sources()[0].Path))
+	// Output: example service.yml
+}

examples/consumers/inheritance.go

@@ -0,0 +1,20 @@
+package consumers
+
+import configkit "gitea.maximumdirect.net/eric/ConfigKit"
+
+// PresetCatalog is ordinary application data; no inheritance fields or
+// registration hooks are required in the typed configuration.
+type PresetCatalog struct {
+	Presets map[string]Preset `yaml:"presets"`
+}
+
+type Preset struct {
+	Enabled  bool                      `yaml:"enabled"`
+	Settings map[string]map[string]int `yaml:"settings"`
+}
+
+// LoadPresets performs one load; callers may inspect inherited presence and
+// source origins on the returned result before choosing a preset to execute.
+func LoadPresets(source configkit.Source) (*configkit.Result[PresetCatalog], error) {
+	return configkit.Load[PresetCatalog](source)
+}

examples/consumers/inheritance_test.go

@@ -0,0 +1,35 @@
+package consumers_test
+
+import (
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+	"gitea.maximumdirect.net/eric/ConfigKit/examples/consumers"
+)
+
+func TestPresetCatalogOneLoadAndDerivation(t *testing.T) {
+	result, err := consumers.LoadPresets(configkit.File(fixture("inheritance", "presets.yml")))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.Config.Presets["base"].Settings["secondary"]["width"] != 10 ||
+		result.Config.Presets["custom"].Settings["secondary"]["width"] != 20 ||
+		result.Config.Presets["custom"].Enabled {
+		t.Fatalf("expanded presets = %#v", result.Config.Presets)
+	}
+	enabled := configkit.Keys("presets", "custom", "enabled")
+	if !result.Metadata().IsExplicit(enabled) {
+		t.Fatal("inherited false lost explicit presence")
+	}
+	info, found := result.Metadata().Lookup(enabled)
+	if !found || info.Origin.Locations[0].SourceID != "source-1" ||
+		len(info.Origin.Inheritance) != 1 || info.Origin.Inheritance[0].From.String() != "/presets/base/enabled" {
+		t.Fatalf("origin and derivation = %#v, %v", info, found)
+	}
+	nested := configkit.Keys("presets", "custom", "settings", "secondary", "width")
+	info, found = result.Metadata().Lookup(nested)
+	if !found || len(info.Origin.Inheritance) != 1 ||
+		info.Origin.Inheritance[0].From.String() != "/presets/custom/settings/primary/width" {
+		t.Fatalf("destination-local derivation = %#v, %v", info, found)
+	}
+}

examples/consumers/layered.go

@@ -0,0 +1,119 @@
+package consumers
+
+import (
+	"embed"
+	"errors"
+	"io/fs"
+	"path"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+//go:embed testdata/native-source testdata/layered-bundle testdata/collection-bundle testdata/ordinary-imports testdata/source-version
+var bundledFiles embed.FS
+
+// BundledConfig is a small configuration loaded directly from an embedded file.
+type BundledConfig struct {
+	Name    string `yaml:"name"`
+	Enabled bool   `yaml:"enabled"`
+}
+
+type PromptBundleConfig struct {
+	Name        string                  `yaml:"name"`
+	Version     string                  `yaml:"version"`
+	Description string                  `yaml:"description"`
+	Prompts     map[string]BundlePrompt `yaml:"prompts"`
+}
+
+type BundlePrompt struct {
+	Summary string `yaml:"summary"`
+}
+
+// LoadPromptBundle demonstrates ordinary Load with opt-in imports whose
+// destinations are declared relative to the entry document.
+func LoadPromptBundle() (*configkit.Result[PromptBundleConfig], error) {
+	files, err := fs.Sub(bundledFiles, "testdata/ordinary-imports")
+	if err != nil {
+		return nil, err
+	}
+	return configkit.Load[PromptBundleConfig](
+		configkit.NewFilesystem("prompt bundle", files).File("config.yml"),
+		configkit.Options[PromptBundleConfig]{Imports: true},
+	)
+}
+
+// LoadBundled demonstrates a native filesystem source without layered options.
+func LoadBundled() (*configkit.Result[BundledConfig], error) {
+	files, err := fs.Sub(bundledFiles, "testdata/native-source")
+	if err != nil {
+		return nil, err
+	}
+	return configkit.Load[BundledConfig](configkit.NewFilesystem("bundled", files).File("config.yml"))
+}
+
+// CatalogConfig keeps resource names and domain rules in the application.
+type CatalogConfig struct {
+	Mode      string            `yaml:"mode"`
+	Enabled   bool              `yaml:"enabled"`
+	Workers   int               `yaml:"workers"`
+	Templates map[string]string `yaml:"templates"`
+	Labels    map[string]string `yaml:"labels"`
+}
+
+// LoadCatalog combines two underlay tiers beneath an independently located
+// host main file. ConfigKit assembles and validates the complete result once.
+func LoadCatalog(mainPath string) (*configkit.Result[CatalogConfig], error) {
+	files, err := fs.Sub(bundledFiles, "testdata/layered-bundle")
+	if err != nil {
+		return nil, err
+	}
+	bundle := configkit.NewFilesystem("catalog bundle", files)
+	return configkit.LoadLayered(configkit.Input{Source: configkit.File(mainPath)},
+		configkit.LayeredOptions[CatalogConfig]{
+			Underlays: []configkit.Underlay{
+				{Inputs: []configkit.Input{{Source: bundle.File("defaults/config.yml"), Imports: true}}},
+				{Inputs: []configkit.Input{{Source: configkit.Mapping("local policy", map[string]any{
+					"workers": 2,
+					"labels":  map[string]any{"tenant": "example"},
+				})}}},
+			},
+			Definition: configkit.Definition[CatalogConfig]{
+				Defaults: func() CatalogConfig { return CatalogConfig{Mode: "demo"} },
+				Validate: validateCatalog,
+			},
+		})
+}
+
+func validateCatalog(configuration *CatalogConfig, validation *configkit.Validation) {
+	if configuration.Mode != "demo" && configuration.Mode != "production" {
+		validation.Error(configkit.Keys("mode"), "must be demo or production")
+	}
+	if configuration.Workers < 0 {
+		validation.Error(configkit.Keys("workers"), "must be nonnegative")
+	}
+	if name := configuration.Templates["welcome"]; name == "." || !fs.ValidPath(name) {
+		validation.Error(configkit.Keys("templates", "welcome"), "must be a relative resource name")
+	}
+}
+
+// ReadWelcome follows the effective template field's one declaring source to
+// its retained resource context. Opening and interpreting the resource remain
+// application work; this does not reopen configuration or change metadata.
+func ReadWelcome(result *configkit.Result[CatalogConfig]) (string, error) {
+	if result == nil {
+		return "", errors.New("catalog result is nil")
+	}
+	info, found := result.Metadata().Lookup(configkit.Keys("templates", "welcome"))
+	if !found || len(info.Origin.Locations) != 1 {
+		return "", errors.New("welcome template has no single declaring source")
+	}
+	context, found := result.SourceContext(info.Origin.Locations[0].SourceID)
+	if !found {
+		return "", errors.New("welcome template has no resource context")
+	}
+	data, err := fs.ReadFile(context.FS, path.Join(context.BaseDir, result.Config.Templates["welcome"]))
+	if err != nil {
+		return "", err
+	}
+	return string(data), nil
+}

examples/consumers/layered_test.go

@@ -0,0 +1,151 @@
+package consumers_test
+
+import (
+	"errors"
+	"fmt"
+	"strings"
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+	"gitea.maximumdirect.net/eric/ConfigKit/examples/consumers"
+)
+
+func Example_nativeFilesystem() {
+	result, err := consumers.LoadBundled()
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println(result.Config.Name, result.Config.Enabled)
+	// Output: embedded false
+}
+
+func Example_rootRelativeImports() {
+	result, err := consumers.LoadPromptBundle()
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	source := result.Sources()[2]
+	fmt.Println(result.Config.Name, result.Config.Version, result.Config.Prompts["brief"].Summary, source.Destination.String(), err)
+	// Output: Root import example 1.0 A root-loaded prompt. /prompts <nil>
+}
+
+func TestPromptBundleUsesRelativeImportDestinations(t *testing.T) {
+	result, err := consumers.LoadPromptBundle()
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.Config.Name != "Root import example" || result.Config.Version != "1.0" || result.Config.Prompts["brief"].Summary != "A root-loaded prompt." {
+		t.Fatalf("root import result = %#v", result.Config)
+	}
+	sources := result.Sources()
+	if len(sources) != 3 || sources[0].Destination.String() != configkit.Keys().String() ||
+		sources[1].Path != "metadata.yml" || sources[1].Destination.String() != configkit.Keys().String() ||
+		sources[2].Path != "prompts/brief.yml" || sources[2].Destination.String() != "/prompts" ||
+		sources[2].ImportedFrom == nil || sources[2].ImportedFrom.SourceID != sources[0].ID {
+		t.Fatalf("root import sources = %#v", sources)
+	}
+}
+
+func Example_layeredCatalog() {
+	result, err := consumers.LoadCatalog(fixture("layered-main", "config.yml"))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	welcome, err := consumers.ReadWelcome(result)
+	fmt.Println(result.Config.Mode, result.Config.Enabled, result.Config.Workers,
+		result.Config.Labels["origin"], result.Config.Labels["tenant"], strings.TrimSpace(welcome), err)
+	// Output: production false 0 bundle example Welcome from the bundle. <nil>
+}
+
+func Example_sourceVersionAdoption() {
+	result, err := consumers.LoadVersionedService(configkit.SourceVersionModeIfPresent)
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	checks, redacted := 0, true
+	for _, source := range result.Sources() {
+		if check := source.VersionCheck; check != nil {
+			checks++
+			redacted = redacted && check.Redacted && check.Version.Text == ""
+		}
+	}
+	required, requiredErr := consumers.LoadVersionedService(configkit.SourceVersionModeRequired)
+	fmt.Println(result.Config.Service.Version, result.Config.Service.Metadata.Release,
+		checks, redacted, required != nil && requiredErr == nil)
+	// Output: service-v2 application-2026.10 2 true true
+}
+
+func TestVersionedServiceModesAndMountedProtection(t *testing.T) {
+	for _, mode := range []configkit.SourceVersionMode{
+		configkit.SourceVersionModeIfPresent,
+		configkit.SourceVersionModeRequired,
+	} {
+		result, err := consumers.LoadVersionedService(mode)
+		if err != nil || result == nil || result.Config.Service.Version != "service-v2" ||
+			result.Config.Service.Name != "example service" || result.Config.Service.Endpoint != "https://service.example.invalid" ||
+			result.Config.Service.Metadata.Release != "application-2026.10" {
+			t.Fatalf("versioned service mode %d = %#v, %v", mode, result, err)
+		}
+		sources := result.Sources()
+		if len(sources) != 2 {
+			t.Fatalf("versioned service sources = %#v", sources)
+		}
+		for _, source := range sources {
+			check := source.VersionCheck
+			if check == nil || check.Path.String() != "/version" || !check.Version.Present ||
+				!check.Redacted || check.Version.Text != "" {
+				t.Fatalf("safe source version evidence = %#v", sources)
+			}
+		}
+	}
+	_, err := consumers.LoadVersionedService(configkit.SourceVersionModeIfPresent,
+		configkit.Override{Path: configkit.Keys("service", "version"), Value: "cli-v3", Flag: "--service-version"})
+	var loadError *configkit.LoadError
+	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 ||
+		loadError.Diagnostics()[0].Code != configkit.CodeOverrideVersion ||
+		loadError.Diagnostics()[0].Path.String() != "/service/version" {
+		t.Fatalf("mounted main version override error = %v", err)
+	}
+}
+
+func TestCatalogRetainsPresenceAndSourceContext(t *testing.T) {
+	result, err := consumers.LoadCatalog(fixture("layered-main", "config.yml"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	for _, key := range []string{"enabled", "workers"} {
+		info, found := result.Metadata().Lookup(configkit.Keys(key))
+		if !found || !info.Explicit || info.Origin.Layer != configkit.LayerBase {
+			t.Fatalf("%s presence = %#v, %v", key, info, found)
+		}
+	}
+	info, found := result.Metadata().Lookup(configkit.Keys("templates", "welcome"))
+	if !found || info.Origin.Layer != configkit.LayerUnderlay || len(info.Origin.Locations) != 1 {
+		t.Fatalf("welcome origin = %#v, %v", info, found)
+	}
+	context, found := result.SourceContext(info.Origin.Locations[0].SourceID)
+	if !found || context.BaseDir != "defaults" {
+		t.Fatalf("welcome context = %#v, %v", context, found)
+	}
+	welcome, err := consumers.ReadWelcome(result)
+	if err != nil || strings.TrimSpace(welcome) != "Welcome from the bundle." {
+		t.Fatalf("welcome = %q, %v", welcome, err)
+	}
+	if result.Config.Labels["tenant"] != "example" || result.Config.Labels["origin"] != "bundle" {
+		t.Fatalf("recursive underlay labels = %#v", result.Config.Labels)
+	}
+}
+
+func TestCatalogValidationRejectsInvalidMode(t *testing.T) {
+	_, err := consumers.LoadCatalog(fixture("layered-main", "invalid.yml"))
+	var loadError *configkit.LoadError
+	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) == 0 ||
+		loadError.Diagnostics()[0].Code != configkit.CodeValidateError ||
+		loadError.Diagnostics()[0].Path.String() != "/mode" {
+		t.Fatalf("invalid mode error = %v", err)
+	}
+}

examples/consumers/prompt_catalog.go

@@ -0,0 +1,67 @@
+package consumers
+
+import (
+	"strings"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+// PromptCatalogConfig is an application-owned prompt collection shape.
+type PromptCatalogConfig struct {
+	Prompts []PromptRecord `yaml:"prompts"`
+}
+
+// PromptRecord keeps its identity and message meaning in the consumer.
+type PromptRecord struct {
+	ID       string   `yaml:"id"`
+	Name     string   `yaml:"name"`
+	Messages []string `yaml:"messages"`
+	Resource string   `yaml:"resource"`
+}
+
+// LoadPromptCatalog discovers explicitly registered prompt records in the main
+// tier and replaces the lower-priority default collection as a whole.
+func LoadPromptCatalog(mainPath string) (*configkit.Result[PromptCatalogConfig], error) {
+	return configkit.LoadLayered(configkit.Input{
+		Source:  configkit.File(mainPath),
+		Imports: true,
+	}, configkit.LayeredOptions[PromptCatalogConfig]{
+		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{
+			Source: configkit.Bytes("default prompts", []byte("prompts:\n  - id: default\n    name: Default prompt\n    messages: [Default message]\n")),
+		}}}},
+		ImportDefaults: configkit.ImportDefaults{
+			Pattern: []string{"curated*.yml", "generated-*.yml"},
+		},
+		Definition: promptCatalogDefinition(),
+	})
+}
+
+// LoadRequiredPromptCatalog keeps the common one-file import shape small.
+func LoadRequiredPromptCatalog(mainPath string) (*configkit.Result[PromptCatalogConfig], error) {
+	return configkit.Load(configkit.File(mainPath), configkit.Options[PromptCatalogConfig]{
+		Imports: true, Definition: promptCatalogDefinition(),
+	})
+}
+
+func promptCatalogDefinition() configkit.Definition[PromptCatalogConfig] {
+	return configkit.Definition[PromptCatalogConfig]{
+		SequenceIdentities: []configkit.SequenceIdentity{
+			configkit.SequenceIdentityAt(configkit.Keys("prompts"), "id"),
+		},
+		Validate: validatePromptCatalog,
+	}
+}
+
+func validatePromptCatalog(configuration *PromptCatalogConfig, validation *configkit.Validation) {
+	for index, prompt := range configuration.Prompts {
+		if strings.TrimSpace(prompt.Name) == "" {
+			validation.Error(configkit.Keys("prompts").Index(index).Key("name"), "must not be empty")
+		}
+		if len(prompt.Messages) == 0 {
+			validation.Error(configkit.Keys("prompts").Index(index).Key("messages"), "must contain at least one message")
+		}
+	}
+	if len(configuration.Prompts) == 0 {
+		validation.Error(configkit.Keys("prompts"), "must contain at least one prompt")
+	}
+}

examples/consumers/prompt_catalog_test.go

@@ -0,0 +1,135 @@
+package consumers_test
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	pathpkg "path"
+	"path/filepath"
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+	"gitea.maximumdirect.net/eric/ConfigKit/examples/consumers"
+)
+
+func Example_identifiedPromptCatalog() {
+	result, err := consumers.LoadPromptCatalog(fixture("prompt-catalog", "config.yml"))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	ids := make([]string, 0, len(result.Config.Prompts))
+	for _, prompt := range result.Config.Prompts {
+		ids = append(ids, prompt.ID)
+	}
+	emptySearches := 0
+	for _, source := range result.Sources() {
+		for _, selection := range source.ImportSelections {
+			if selection.Selector == configkit.ImportSelectorDirectory && selection.Outcome == configkit.ImportSelectionNone {
+				emptySearches++
+			}
+		}
+	}
+	fmt.Println(ids, emptySearches, err)
+	// Output: [weather curated welcome main] 1 <nil>
+}
+
+func Example_requiredPromptCatalog() {
+	result, err := consumers.LoadRequiredPromptCatalog(fixture("prompt-catalog", "simple.yml"))
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	fmt.Println(result.Config.Prompts[0].ID, err)
+	// Output: required <nil>
+}
+
+func TestPromptCatalogImportsRegisteredItemsAndReplacesDefaults(t *testing.T) {
+	result, err := consumers.LoadPromptCatalog(fixture("prompt-catalog", "config.yml"))
+	if err != nil {
+		var loadError *configkit.LoadError
+		if errors.As(err, &loadError) {
+			t.Fatalf("load prompt catalog: %v (%#v)", err, loadError.Diagnostics())
+		}
+		t.Fatal(err)
+	}
+	if len(result.Config.Prompts) != 4 {
+		t.Fatalf("prompt records = %#v", result.Config.Prompts)
+	}
+	ids := []string{"weather", "curated", "welcome", "main"}
+	for index, id := range ids {
+		if result.Config.Prompts[index].ID != id {
+			t.Fatalf("prompt %d ID = %q, want %q", index, result.Config.Prompts[index].ID, id)
+		}
+	}
+	for _, prompt := range result.Config.Prompts {
+		if prompt.ID == "default" {
+			t.Fatalf("lower-priority default survived main sequence replacement: %#v", result.Config.Prompts)
+		}
+		if prompt.ID == "ignored" {
+			t.Fatalf("excluded generated prompt was selected: %#v", result.Config.Prompts)
+		}
+	}
+
+	var itemImports, helperImports int
+	for _, source := range result.Sources() {
+		switch filepath.Base(source.Path) {
+		case "curated.yml", "weather-feature.yml", "generated-welcome.yml":
+			if source.PlacementMode != configkit.PlacementModeSequenceItem || source.Destination.String() != "/prompts" {
+				t.Fatalf("item source placement = %#v", source)
+			}
+			itemImports++
+		case "curated-id.yml":
+			if source.PlacementMode != configkit.PlacementModeMapping || source.ImportedFrom == nil {
+				t.Fatalf("helper source = %#v", source)
+			}
+			helperImports++
+		}
+	}
+	if itemImports != 3 || helperImports != 1 {
+		t.Fatalf("item imports = %d, helper imports = %d, sources = %#v", itemImports, helperImports, result.Sources())
+	}
+	if result.Config.Prompts[1].ID != "curated" {
+		t.Fatalf("helper did not provide prompt ID: %#v", result.Config.Prompts[1])
+	}
+}
+
+func TestPromptCatalogMountsResourceFromScheduledPromptOrigin(t *testing.T) {
+	result, err := consumers.LoadPromptCatalog(fixture("prompt-catalog", "config.yml"))
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.Config.Prompts[2].ID != "welcome" || result.Config.Prompts[2].Resource != "welcome.txt" {
+		t.Fatalf("scheduled resource prompt = %#v", result.Config.Prompts)
+	}
+	resourcePath := configkit.Keys("prompts").Index(2).Key("resource")
+	info, ok := result.Metadata().Lookup(resourcePath)
+	if !ok || len(info.Origin.Locations) != 1 {
+		t.Fatalf("resource origin = %#v, %v", info, ok)
+	}
+	context, ok := result.SourceContext(info.Origin.Locations[0].SourceID)
+	if !ok || context.FS == nil || filepath.Base(context.BaseDir) != "prompts" {
+		t.Fatalf("resource source context = %#v, %v", context, ok)
+	}
+	contents, err := fs.ReadFile(context.FS, pathpkg.Join(context.BaseDir, result.Config.Prompts[2].Resource))
+	if err != nil || string(contents) != "Welcome resource text.\n" {
+		t.Fatalf("mounted resource = %q, %v", contents, err)
+	}
+}
+
+func TestRequiredPromptCatalogUsesOneRequiredFile(t *testing.T) {
+	result, err := consumers.LoadRequiredPromptCatalog(fixture("prompt-catalog", "simple.yml"))
+	if err != nil || len(result.Config.Prompts) != 1 || result.Config.Prompts[0].ID != "required" {
+		t.Fatalf("simple required prompt = %#v, %v", result, err)
+	}
+}
+
+func TestPromptCatalogLeavesDomainValidationWithConsumer(t *testing.T) {
+	_, err := consumers.LoadPromptCatalog(fixture("prompt-catalog", "invalid.yml"))
+	var loadError *configkit.LoadError
+	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 ||
+		loadError.Diagnostics()[0].Code != configkit.CodeValidateError ||
+		loadError.Diagnostics()[0].Path.String() != "/prompts/0/messages" {
+		t.Fatalf("consumer domain validation error = %v", err)
+	}
+}

examples/consumers/sequence_catalog.go

@@ -0,0 +1,145 @@
+package consumers
+
+import (
+	"errors"
+	"fmt"
+	"io/fs"
+	"os"
+	"path"
+	"path/filepath"
+	"strings"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+// SequenceCatalogConfig is a source-backed prompt catalog with an application
+// supplied run label and a value derived from that label during resolution.
+type SequenceCatalogConfig struct {
+	RunLabel      string                 `yaml:"run_label"`
+	ResolvedLabel string                 `yaml:"resolved_label"`
+	Prompts       []SequenceCatalogEntry `yaml:"prompts"`
+}
+
+// SequenceCatalogEntry keeps prompt meaning, resources, and credentials in the
+// consuming application while ConfigKit handles collection assembly.
+type SequenceCatalogEntry struct {
+	ID          string           `yaml:"id"`
+	Name        string           `yaml:"name"`
+	Description string           `yaml:"description"`
+	Messages    []string         `yaml:"messages"`
+	Resource    string           `yaml:"resource"`
+	Credential  configkit.Secret `yaml:"credential"`
+}
+
+// LoadSequenceCatalog searches its caller-selected main path before a custom
+// fallback directory, assembles imported fragments over a file-backed underlay,
+// applies one selected collection overlay, then resolves and validates once.
+func LoadSequenceCatalog(mainPath, overlayName, runLabel string) (*configkit.Result[SequenceCatalogConfig], error) {
+	absoluteMain, err := filepath.Abs(mainPath)
+	if err != nil {
+		return nil, err
+	}
+	root := filepath.Dir(absoluteMain)
+	filesystem := configkit.NewFilesystem("sequence catalog", os.DirFS(root))
+	filesystemContext := &configkit.FilesystemContext{BaseDir: ".", Root: ".", FS: &filesystem}
+	mainSearch := configkit.SearchConfig("", configkit.Searches(
+		configkit.Paths(absoluteMain),
+		configkit.SearchDirectory(filepath.Join(root, "fallback"), configkit.DirectorySearchOptions{
+			Filenames: []configkit.FilenameGroup{configkit.CustomFilenames(filepath.Base(absoluteMain))},
+		}),
+	), configkit.SearchOptions{Required: true})
+	definition := configkit.Definition[SequenceCatalogConfig]{
+		SequenceIdentities: []configkit.SequenceIdentity{
+			configkit.SequenceIdentityAt(configkit.Keys("prompts"), "id"),
+		},
+		Resolve: func(configuration *SequenceCatalogConfig, resolution *configkit.Resolution) error {
+			configuration.ResolvedLabel = "for:" + configuration.RunLabel
+			resolution.Record(configkit.Keys("resolved_label"), configkit.ChangeNormalization,
+				"derive the resolved label from the selected run label", configkit.Keys("run_label"))
+			return nil
+		},
+		Validate: validateSequenceCatalog,
+	}
+	return configkit.LoadLayered(configkit.Input{
+		Source:     mainSearch,
+		Imports:    true,
+		Filesystem: &configkit.FilesystemContext{Root: root},
+	}, configkit.LayeredOptions[SequenceCatalogConfig]{
+		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{
+			Source: filesystem.File("underlay.yml"),
+		}}}},
+		Overlay:           overlayName,
+		OverlayFilesystem: filesystemContext,
+		Overrides: []configkit.Override{{
+			Path: configkit.Keys("run_label"), Value: runLabel, Flag: "--run-label",
+		}},
+		Definition: definition,
+	})
+}
+
+// ReadSequenceCatalogResource follows the final prompt field's source context,
+// including when record inheritance retained a resource from an underlay.
+func ReadSequenceCatalogResource(result *configkit.Result[SequenceCatalogConfig], promptID string) (string, error) {
+	if result == nil {
+		return "", errors.New("sequence catalog result is nil")
+	}
+	for index, prompt := range result.Config.Prompts {
+		if prompt.ID != promptID {
+			continue
+		}
+		resourcePath := configkit.Keys("prompts").Index(index).Key("resource")
+		info, found := result.Metadata().Lookup(resourcePath)
+		if !found || len(info.Origin.Locations) != 1 {
+			return "", errors.New("prompt resource has no single declaring source")
+		}
+		context, found := result.SourceContext(info.Origin.Locations[0].SourceID)
+		if !found {
+			return "", errors.New("prompt resource source context is unavailable")
+		}
+		data, err := fs.ReadFile(context.FS, path.Join(context.BaseDir, prompt.Resource))
+		if err != nil {
+			return "", fmt.Errorf("read prompt resource: %w", err)
+		}
+		return string(data), nil
+	}
+	return "", fmt.Errorf("prompt %q is unavailable", promptID)
+}
+
+func validateSequenceCatalog(configuration *SequenceCatalogConfig, validation *configkit.Validation) {
+	for index, prompt := range configuration.Prompts {
+		if strings.TrimSpace(prompt.Name) == "" {
+			validation.Error(configkit.Keys("prompts").Index(index).Key("name"), "must not be empty")
+		}
+		if len(prompt.Messages) == 0 {
+			validation.Error(configkit.Keys("prompts").Index(index).Key("messages"), "must contain at least one message")
+		}
+	}
+	if len(configuration.Prompts) == 0 {
+		validation.Error(configkit.Keys("prompts"), "must contain at least one prompt")
+	}
+}
+
+// NamespacedMapCatalogConfig demonstrates typed application maps whose
+// independent prompt sequences use root and dynamic namespace registrations.
+type NamespacedMapCatalogConfig struct {
+	Prompts     []map[string]any          `yaml:"prompts"`
+	Collections map[string]map[string]any `yaml:"collections"`
+}
+
+// LoadNamespacedMapCatalog applies the same scalar identity constraint to one
+// root collection and each namespace's independently scoped collection.
+func LoadNamespacedMapCatalog(source configkit.Source) (*configkit.Result[NamespacedMapCatalogConfig], error) {
+	selector := configkit.SequenceSelector{
+		configkit.SequenceLiteralKey("collections"),
+		configkit.SequenceAnyMappingKey(),
+		configkit.SequenceLiteralKey("prompts"),
+	}
+	return configkit.Load(source, configkit.Options[NamespacedMapCatalogConfig]{
+		Definition: configkit.Definition[NamespacedMapCatalogConfig]{
+			SequenceIdentities: []configkit.SequenceIdentity{
+				configkit.SequenceIdentityAt(configkit.Keys("prompts"), "id"),
+				configkit.SequenceIdentityMatching(selector, "id"),
+			},
+		},
+	})
+}

examples/consumers/sequence_catalog_test.go

@@ -0,0 +1,239 @@
+package consumers_test
+
+import (
+	"bytes"
+	"errors"
+	"fmt"
+	"os"
+	"strings"
+	"testing"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+	"gitea.maximumdirect.net/eric/ConfigKit/examples/consumers"
+)
+
+func Example_sequenceCatalog() {
+	const oldSecret = "CONFIGKIT_SEQUENCE_CATALOG_OLD_SECRET"
+	const newSecret = "CONFIGKIT_SEQUENCE_CATALOG_NEW_SECRET"
+	restoreOld, restoreNew := preserveEnvironment(oldSecret), preserveEnvironment(newSecret)
+	defer restoreOld()
+	defer restoreNew()
+	_ = os.Setenv(oldSecret, "disposable-old-example-credential")
+	_ = os.Setenv(newSecret, "disposable-new-example-credential")
+
+	result, err := consumers.LoadSequenceCatalog(fixture("sequence-catalog", "config.yml"), "upsert", "preview")
+	if err != nil {
+		fmt.Println(err)
+		return
+	}
+	ids := make([]string, 0, len(result.Config.Prompts))
+	for _, prompt := range result.Config.Prompts {
+		ids = append(ids, prompt.ID)
+	}
+	shared := configkit.Keys("prompts").Index(1).Key("name")
+	info, _ := result.Metadata().Lookup(shared)
+	resource, resourceErr := consumers.ReadSequenceCatalogResource(result, "concise")
+	fmt.Println(ids, result.Config.ResolvedLabel, info.Explicit, len(result.Metadata().History(shared)), resource, resourceErr == nil, err)
+	// Output: [foundation shared welcome concise extra] for:preview true 2 Foundation resource text.
+	//  true <nil>
+}
+
+func TestSequenceCatalogSelectedOverlayOperations(t *testing.T) {
+	const oldSecret = "CONFIGKIT_SEQUENCE_CATALOG_OLD_SECRET"
+	const newSecret = "CONFIGKIT_SEQUENCE_CATALOG_NEW_SECRET"
+	t.Setenv(oldSecret, "sequence-catalog-old-canary")
+	t.Setenv(newSecret, "sequence-catalog-new-canary")
+
+	tests := []struct {
+		name    string
+		wantIDs []string
+		shared  *consumers.SequenceCatalogEntry
+	}{
+		{name: "append", wantIDs: []string{"foundation", "shared", "welcome", "concise", "extra"}},
+		{name: "upsert", wantIDs: []string{"foundation", "shared", "welcome", "concise", "extra"}, shared: &consumers.SequenceCatalogEntry{ID: "shared", Name: "Shared replacement", Messages: []string{"Replacement message"}, Credential: configkit.SecretEnv(newSecret)}},
+		{name: "replace", wantIDs: []string{"replacement", "last"}},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			result, err := consumers.LoadSequenceCatalog(fixture("sequence-catalog", "config.yml"), test.name, "test")
+			if err != nil {
+				var loadError *configkit.LoadError
+				if errors.As(err, &loadError) {
+					t.Fatalf("load selected overlay: %v (%#v)", err, loadError.Diagnostics())
+				}
+				t.Fatal(err)
+			}
+			gotIDs := make([]string, 0, len(result.Config.Prompts))
+			for _, prompt := range result.Config.Prompts {
+				gotIDs = append(gotIDs, prompt.ID)
+			}
+			if strings.Join(gotIDs, ",") != strings.Join(test.wantIDs, ",") {
+				t.Fatalf("prompt order = %v, want %v", gotIDs, test.wantIDs)
+			}
+			if test.shared == nil {
+				return
+			}
+			shared := result.Config.Prompts[1]
+			if shared.ID != test.shared.ID || shared.Name != test.shared.Name || len(shared.Messages) != 1 ||
+				shared.Messages[0] != test.shared.Messages[0] || shared.Description != "" || shared.Resource != "" || shared.Credential.EnvName() != newSecret {
+				t.Fatalf("upsert did not replace the complete matched record: %#v", shared)
+			}
+		})
+	}
+}
+
+func TestSequenceCatalogInspectionTracksResourcesAndSecretHistory(t *testing.T) {
+	const oldSecret = "CONFIGKIT_SEQUENCE_CATALOG_OLD_SECRET"
+	const newSecret = "CONFIGKIT_SEQUENCE_CATALOG_NEW_SECRET"
+	const oldCanary = "sequence-catalog-old-canary"
+	const newCanary = "sequence-catalog-new-canary"
+	t.Setenv(oldSecret, oldCanary)
+	t.Setenv(newSecret, newCanary)
+
+	result, err := consumers.LoadSequenceCatalog(fixture("sequence-catalog", "config.yml"), "upsert", "history")
+	if err != nil {
+		var loadError *configkit.LoadError
+		if errors.As(err, &loadError) {
+			t.Fatalf("load sequence catalog: %v (%#v)", err, loadError.Diagnostics())
+		}
+		t.Fatal(err)
+	}
+	resourcePath := configkit.Keys("prompts").Index(3).Key("resource")
+	resourceInfo, found := result.Metadata().Lookup(resourcePath)
+	if !found || len(resourceInfo.Origin.Locations) != 1 || len(resourceInfo.Origin.Inheritance) != 1 {
+		t.Fatalf("inherited resource inspection = %#v, %v", resourceInfo, found)
+	}
+	resource, err := consumers.ReadSequenceCatalogResource(result, "concise")
+	if err != nil || resource != "Foundation resource text.\n" {
+		t.Fatalf("resource from inherited source context = %q, %v", resource, err)
+	}
+	if len(result.Metadata().History(configkit.Keys("resolved_label"))) == 0 {
+		t.Fatal("recorded CLI-driven resolution was absent from final inspection")
+	}
+	credentialPath := configkit.Keys("prompts").Index(1).Key("credential")
+	credentialHistory := result.Metadata().History(credentialPath)
+	if len(credentialHistory) == 0 {
+		t.Fatal("upsert did not retain the replaced secret reference in history")
+	}
+	var explanation bytes.Buffer
+	if err := result.WriteExplanation(&explanation, credentialPath); err != nil {
+		t.Fatal(err)
+	}
+	if strings.Contains(explanation.String(), oldCanary) || strings.Contains(explanation.String(), newCanary) {
+		t.Fatalf("secret explanation exposed a credential value: %s", explanation.String())
+	}
+}
+
+func TestNamespacedTypedMapIdentityScopesAreIndependent(t *testing.T) {
+	source := configkit.Bytes("namespaced maps", []byte(`
+prompts:
+  - id: shared
+    text: root prompt
+collections:
+  team:
+    prompts:
+      - id: shared
+        text: team prompt
+  operations:
+    prompts:
+      - id: shared
+        text: operations prompt
+`))
+	result, err := consumers.LoadNamespacedMapCatalog(source)
+	if err != nil {
+		t.Fatal(err)
+	}
+	if result.Config.Prompts[0]["text"] != "root prompt" ||
+		result.Config.Collections["team"]["prompts"].([]any)[0].(map[string]any)["text"] != "team prompt" ||
+		result.Config.Collections["operations"]["prompts"].([]any)[0].(map[string]any)["text"] != "operations prompt" {
+		t.Fatalf("typed map collections = %#v", result.Config)
+	}
+}
+
+func TestNamespacedTypedMapIdentityFindsCollectionsIntroducedByInheritance(t *testing.T) {
+	result, err := consumers.LoadNamespacedMapCatalog(configkit.Bytes("inherited namespace", []byte(`
+collections:
+  source:
+    prompts:
+      - id: shared
+        text: inherited prompt
+  copied:
+    extends: source
+`)))
+	if err != nil {
+		t.Fatal(err)
+	}
+	copied := result.Config.Collections["copied"]["prompts"].([]any)
+	if len(copied) != 1 || copied[0].(map[string]any)["text"] != "inherited prompt" {
+		t.Fatalf("inherited typed-map collection = %#v", result.Config.Collections["copied"])
+	}
+}
+
+func Example_yamlDeclaredIdentityOnly() {
+	result, err := configkit.Load(configkit.Bytes("YAML identity only", []byte(`
+configkit:
+  sequences:
+    - destination: [prompts]
+      key: id
+prompts:
+  - id: initial
+`)), configkit.Options[map[string]any]{
+		Overrides: []configkit.Override{{
+			Path: configkit.Keys("prompts"),
+			Value: []any{
+				map[string]any{"id": "same"},
+				map[string]any{"id": "same"},
+			},
+			Flag: "--prompts",
+		}},
+	})
+	fmt.Println(len(result.Config["prompts"].([]any)), err)
+	// Output: 2 <nil>
+}
+
+func TestYAMLDeclaredIdentityDoesNotRegisterFinalTypedConstraint(t *testing.T) {
+	result, err := configkit.Load(configkit.Bytes("YAML identity only", []byte(`
+configkit:
+  sequences:
+    - destination: [prompts]
+      key: id
+prompts:
+  - id: initial
+`)), configkit.Options[map[string]any]{
+		Overrides: []configkit.Override{{
+			Path: configkit.Keys("prompts"),
+			Value: []any{
+				map[string]any{"id": "same"},
+				map[string]any{"id": "same"},
+			},
+			Flag: "--prompts",
+		}},
+	})
+	if err != nil {
+		t.Fatalf("YAML-only identity incorrectly became an application constraint: %v", err)
+	}
+	prompts := result.Config["prompts"].([]any)
+	if len(prompts) != 2 || prompts[0].(map[string]any)["id"] != prompts[1].(map[string]any)["id"] {
+		t.Fatalf("CLI result = %#v", result.Config)
+	}
+}
+
+func TestNamespacedTypedMapRejectsDuplicatesWithinOneCollection(t *testing.T) {
+	_, err := consumers.LoadNamespacedMapCatalog(configkit.Bytes("duplicate namespace", []byte(`
+collections:
+  team:
+    prompts:
+      - id: duplicate
+      - id: duplicate
+`)))
+	var loadError *configkit.LoadError
+	if !errors.As(err, &loadError) || len(loadError.Diagnostics()) != 1 ||
+		loadError.Diagnostics()[0].Code != configkit.CodeComposeConflict ||
+		loadError.Diagnostics()[0].Path.String() != "/collections/team/prompts" {
+		diagnostics := []configkit.Diagnostic(nil)
+		if loadError != nil {
+			diagnostics = loadError.Diagnostics()
+		}
+		t.Fatalf("duplicate namespaced identity error = %v (%#v)", err, diagnostics)
+	}
+}

examples/consumers/source_version.go

@@ -0,0 +1,64 @@
+package consumers
+
+import (
+	"errors"
+	"io/fs"
+
+	configkit "gitea.maximumdirect.net/eric/ConfigKit"
+)
+
+// VersionedServiceConfig demonstrates a mounted main input whose source-local
+// schema version is retained at the effective service path.
+type VersionedServiceConfig struct {
+	Service struct {
+		Version  string `yaml:"version"`
+		Name     string `yaml:"name"`
+		Endpoint string `yaml:"endpoint"`
+		Metadata struct {
+			Release string `yaml:"release"`
+		} `yaml:"metadata"`
+	} `yaml:"service"`
+}
+
+// LoadVersionedService checks the main and underlay declarations with one
+// application policy. The local rule path is "version" for each source; the
+// main input's destination places its protected value at /service/version.
+// Optional CLI overrides are passed through to ConfigKit for normal protection.
+func LoadVersionedService(mode configkit.SourceVersionMode, overrides ...configkit.Override) (*configkit.Result[VersionedServiceConfig], error) {
+	files, err := fs.Sub(bundledFiles, "testdata/source-version")
+	if err != nil {
+		return nil, err
+	}
+	main, err := fs.ReadFile(files, "main.yml")
+	if err != nil {
+		return nil, err
+	}
+	underlay, err := fs.ReadFile(files, "underlay.yml")
+	if err != nil {
+		return nil, err
+	}
+	definition := configkit.Definition[VersionedServiceConfig]{
+		Version: &configkit.VersionRule{
+			Path: configkit.Keys("version"),
+			Check: func(version configkit.Version, _ *configkit.Validation) error {
+				if !version.Present || version.Null || version.Text == "" {
+					return errors.New("a nonempty source version is required")
+				}
+				return nil
+			},
+		},
+		Secret: func(path configkit.Path) bool {
+			return path.String() == "/service/version"
+		},
+	}
+	return configkit.LoadLayered(configkit.Input{
+		Source: configkit.Bytes("service main", main), Destination: configkit.Keys("service"),
+	}, configkit.LayeredOptions[VersionedServiceConfig]{
+		Definition:        definition,
+		SourceVersionMode: mode,
+		Overrides:         overrides,
+		Underlays: []configkit.Underlay{{Inputs: []configkit.Input{{
+			Source: configkit.Bytes("service defaults", underlay), Destination: configkit.Keys("service"),
+		}}}},
+	})
+}

examples/consumers/testdata/collection-bundle/collections/weather/collection.yml

@@ -0,0 +1,9 @@
+configkit:
+  imports:
+    - path: metadata.yml
+      destination: []
+    - path: prompts/index.yml
+      destination: [prompts]
+    - path: profiles/index.yml
+      destination: [profiles]
+name: Weather Reporter

examples/consumers/testdata/collection-bundle/collections/weather/metadata.yml

@@ -0,0 +1,4 @@
+configkit:
+  imports:
+    - path: version.yml
+description: Imported collection metadata.

examples/consumers/testdata/collection-bundle/collections/weather/profiles/compact.yml

@@ -0,0 +1,3 @@
+compact:
+  format: text
+  temperature: 0.2

examples/consumers/testdata/collection-bundle/collections/weather/profiles/index.yml

@@ -0,0 +1,4 @@
+configkit:
+  imports:
+    - path: compact.yml
+    - path: weather.yml

examples/consumers/testdata/collection-bundle/collections/weather/profiles/weather.yml

@@ -0,0 +1,3 @@
+weather:
+  extends: compact
+  temperature: 0.4

examples/consumers/testdata/collection-bundle/collections/weather/prompts/brief.yml

@@ -0,0 +1,7 @@
+brief:
+  version: "1"
+  default_profile: compact
+  content_file: welcome.txt
+  messages:
+    - role: user
+      content: Write a concise weather summary.

examples/consumers/testdata/collection-bundle/collections/weather/prompts/custom.yml

@@ -0,0 +1,3 @@
+custom:
+  extends: brief
+  default_profile: weather

examples/consumers/testdata/collection-bundle/collections/weather/prompts/index.yml

@@ -0,0 +1,4 @@
+configkit:
+  imports:
+    - path: brief.yml
+    - path: custom.yml

examples/consumers/testdata/collection-bundle/collections/weather/prompts/welcome.txt

@@ -0,0 +1 @@
+Welcome to the weather collection.

examples/consumers/testdata/collection-bundle/collections/weather/version.yml

@@ -0,0 +1 @@
+version: "2.4.0"

examples/consumers/testdata/collection-bundle/operators/weather-prompt-version.yml

@@ -0,0 +1,2 @@
+brief:
+  version: "2"

examples/consumers/testdata/inheritance/presets.yml

@@ -0,0 +1,10 @@
+presets:
+  base:
+    enabled: false
+    settings:
+      primary: {width: 10}
+      secondary: {extends: primary}
+  custom:
+    extends: base
+    settings:
+      primary: {width: 20}

examples/consumers/testdata/layered-bundle/defaults/config.yml

@@ -0,0 +1,7 @@
+configkit:
+  imports:
+    - path: ../shared.yml
+enabled: true
+workers: 4
+templates:
+  welcome: messages/welcome.txt

examples/consumers/testdata/layered-bundle/defaults/messages/welcome.txt

@@ -0,0 +1 @@
+Welcome from the bundle.

examples/consumers/testdata/layered-bundle/shared.yml

@@ -0,0 +1,2 @@
+labels:
+  origin: bundle

examples/consumers/testdata/layered-main/config.yml

@@ -0,0 +1,3 @@
+mode: production
+enabled: false
+workers: 0

examples/consumers/testdata/layered-main/invalid.yml

@@ -0,0 +1 @@
+mode: unsupported

examples/consumers/testdata/native-source/config.yml

@@ -0,0 +1,2 @@
+name: embedded
+enabled: false

examples/consumers/testdata/ordinary-imports/config.yml

@@ -0,0 +1,6 @@
+configkit:
+  imports:
+    - path: metadata.yml
+    - path: prompts/brief.yml
+      destination: [prompts]
+name: Root import example

examples/consumers/testdata/ordinary-imports/metadata.yml

@@ -0,0 +1,2 @@
+version: "1.0"
+description: Metadata imported into the root document.

examples/consumers/testdata/ordinary-imports/prompts/brief.yml

@@ -0,0 +1,2 @@
+brief:
+  summary: A root-loaded prompt.

examples/consumers/testdata/prompt-catalog/config.yml

@@ -0,0 +1,19 @@
+configkit:
+  sequences:
+    - destination: [prompts]
+      key: id
+      mode: replace
+  imports:
+    - dir: prompts
+      exclude: [generated-ignored.yml]
+      destination: [prompts]
+      placement: sequence-item
+    - dir: featured
+      pattern: [weather-*.yml]
+      destination: [prompts]
+      placement: sequence-item
+    - dir: optional
+prompts:
+  - id: main
+    name: Main authored prompt
+    messages: [Use the main prompt.]

examples/consumers/testdata/prompt-catalog/featured/weather-feature.yml

@@ -0,0 +1,4 @@
+id: weather
+name: Weather forecast
+messages:
+  - Describe today's forecast.

examples/consumers/testdata/prompt-catalog/invalid.yml

@@ -0,0 +1,9 @@
+configkit:
+  sequences:
+    - destination: [prompts]
+      key: id
+      mode: replace
+prompts:
+  - id: invalid
+    name: Invalid prompt
+    messages: []

examples/consumers/testdata/prompt-catalog/optional/ignored.txt

@@ -0,0 +1 @@
+This file does not match the application import defaults.

examples/consumers/testdata/prompt-catalog/prompts/curated.yml

@@ -0,0 +1,6 @@
+configkit:
+  imports:
+    - path: helpers/curated-id.yml
+name: Curated summary
+messages:
+  - Summarize the supplied content.

examples/consumers/testdata/prompt-catalog/prompts/generated-ignored.yml

@@ -0,0 +1,3 @@
+id: ignored
+name: Excluded generated prompt
+messages: [This record is excluded.]

examples/consumers/testdata/prompt-catalog/prompts/generated-welcome.yml

@@ -0,0 +1,5 @@
+id: welcome
+name: Welcome
+messages:
+  - Welcome the user.
+resource: welcome.txt

examples/consumers/testdata/prompt-catalog/prompts/helpers/curated-id.yml

@@ -0,0 +1 @@
+id: curated

examples/consumers/testdata/prompt-catalog/prompts/required.yml

@@ -0,0 +1,3 @@
+id: required
+name: Required prompt
+messages: [Use the required prompt.]

examples/consumers/testdata/prompt-catalog/prompts/welcome.txt

@@ -0,0 +1 @@
+Welcome resource text.

examples/consumers/testdata/prompt-catalog/simple.yml

@@ -0,0 +1,7 @@
+configkit:
+  imports:
+    - path: prompts/required.yml
+      required: true
+      destination: [prompts]
+      placement: sequence-item
+prompts: []

examples/consumers/testdata/sequence-catalog/config.yml

@@ -0,0 +1,7 @@
+run_label: source-default
+configkit:
+  imports:
+    - dir: fragments
+      pattern: '*.yml'
+      destination: [prompts]
+      placement: sequence-item

examples/consumers/testdata/sequence-catalog/foundation.txt

@@ -0,0 +1 @@
+Foundation resource text.

examples/consumers/testdata/sequence-catalog/fragments/01-welcome.yml

@@ -0,0 +1,4 @@
+id: welcome
+name: Welcome
+messages: [Welcome message]
+credential: CONFIGKIT_SEQUENCE_CATALOG_OLD_SECRET

examples/consumers/testdata/sequence-catalog/fragments/02-concise.yml

@@ -0,0 +1,3 @@
+id: concise
+extends: {id: foundation}
+name: Concise

examples/consumers/testdata/sequence-catalog/overlays/append.yml

@@ -0,0 +1,10 @@
+configkit:
+  sequences:
+    - destination: [prompts]
+      key: id
+      mode: append
+prompts:
+  - id: extra
+    name: Extra
+    messages: [Extra message]
+    credential: CONFIGKIT_SEQUENCE_CATALOG_OLD_SECRET