Add feature roadmap and implementation plan for profile inspection API

docs/roadmap/future.md

@@ -33,26 +33,10 @@ consumers.
 
 ## Ideas
 
-Executable preparation handles have been selected for active planning in the
+Prompt-independent profile inspection has been selected for active planning in
-[focused feature roadmap](prepared-execution.md). The remaining ideas are
+the [focused feature roadmap](profile-inspection.md). The remaining ideas are
 still available for future selection.
 
-### Prompt-independent profile inspection
-
-Provide exact profile lookup and structural resolution without requiring a
-synthetic prompt, placeholder inputs, or model generation. This shared need is
-described by
-[Notarius](notarius-promptkit-wishlist.md#priority-2-prompt-independent-profile-inspection)
-and
-[Weatherreporter](weatherreporter-promptkit-wishlist.md#priority-3-prompt-independent-profile-inspection).
-
-- Apply ordinary built-in, file-backed, and programmatic profile precedence.
-- Validate referenced backend membership and the structurally resolved
-  execution target.
-- Report credential requirements and environment-variable names without
-  exposing credential values or requiring current credential availability.
-- Support exact lookup by profile ID; enumeration is not required initially.
-
 ### Prompt-definition inspection
 
 Provide exact prompt-definition lookup without rendering, placeholder inputs,

docs/roadmap/notarius-promptkit-wishlist.md

@@ -88,8 +88,8 @@ corresponds atomically to the actual execution.
 
 ## Priority 2: Prompt-Independent Profile Inspection
 
-**Disposition:** Accepted into the
+**Disposition:** Covered by the accepted
-[future catalog](future.md#prompt-independent-profile-inspection).
+[prompt-independent profile inspection](profile-inspection.md) roadmap.
 
 ### Downstream need
 

docs/roadmap/profile-inspection.md

@@ -0,0 +1,246 @@
+# Prompt-Independent Profile Inspection
+
+**Status:** Accepted.
+
+## Purpose
+
+Allow consumers to look up one execution profile by ID and inspect its
+structurally resolved model target without selecting a prompt, supplying
+placeholder inputs, checking credential availability, or invoking a model.
+
+This provides a direct configuration-validation boundary for
+[Notarius](notarius-promptkit-wishlist.md#priority-2-prompt-independent-profile-inspection)
+and
+[Weatherreporter](weatherreporter-promptkit-wishlist.md#priority-3-prompt-independent-profile-inspection).
+
+## Motivation
+
+Both downstream consumers need to reject invalid configured profile IDs before
+starting application work. They currently have to construct a synthetic prompt
+and call `Engine.Prepare` merely to exercise profile loading, backend lookup,
+and execution-target resolution.
+
+That workaround couples profile validation to unrelated prompt definitions,
+fixture inputs, rendering, schema behavior, and current credential
+availability. Promptkit already owns profile precedence, backend membership,
+and target resolution, so it should expose that cohesive capability directly.
+
+## Consumer Workflow
+
+The target public workflow is:
+
+```go
+inspection, err := engine.InspectProfile(ctx, profileID)
+if err != nil {
+	// Reject or report the configured profile.
+	return
+}
+
+target := inspection.EffectiveModelParams
+if target.APIKeyEnv != "" {
+	// Apply application policy for the named environment variable.
+}
+```
+
+The target public surface is:
+
+```go
+type ProfileInspection struct {
+	ProfileID           string
+	EffectiveModelParams ExecutionTarget
+	APIKeyRequired      bool
+}
+
+func (e *Engine) InspectProfile(
+	ctx context.Context,
+	profileID string,
+) (*ProfileInspection, error)
+```
+
+The declarations and GoDoc will own the exact implemented contract. The
+important public shape is exact lookup through the existing engine, one
+caller-owned inspection value, the resolved `ExecutionTarget`, and an explicit
+signal for a direct API-key requirement.
+
+`EffectiveModelParams.BackendID` identifies the selected registered backend
+and remains empty for endpoint-only profiles.
+`EffectiveModelParams.APIKeyEnv` reports the effective credential environment
+variable name. `APIKeyRequired` reports that the profile requires a direct
+request credential instead. These states are mutually exclusive after normal
+profile and backend precedence is applied.
+
+`ProfileInspection` does not need a stable JSON representation. Consumers that
+persist application configuration or diagnostics can select the fields their
+own format requires.
+
+## Lookup And Precedence
+
+`InspectProfile` requires a non-blank explicit profile ID. It trims surrounding
+whitespace and otherwise performs the same case-sensitive exact lookup used by
+ordinary execution.
+
+Lookup applies the engine's normal profile-source precedence:
+
+- programmatic profiles supplied through `WithProfiles`;
+- the configured file, directory, or `fs.FS` profile source; and
+- the built-in profile catalog.
+
+A valid higher-precedence match shadows a lower-precedence profile with the
+same ID. A malformed or unreadable higher-precedence match fails rather than
+silently falling back. The
+[profile format reference](../formats.md#profile-definitions) remains the
+canonical owner of profile-source and file-format behavior.
+
+Inspection never derives a profile ID from a prompt's `default_profile`; the
+caller is inspecting one explicitly named profile.
+
+## Structural Resolution
+
+Inspection loads and validates the selected profile, verifies that a named
+backend exists in the engine's immutable backend registry, and applies normal
+framework-default, backend, and profile precedence to produce the effective
+target.
+
+For the same engine state and profile ID, with no per-run execution override,
+the inspected target must match the target that ordinary preparation would
+resolve before applying request credentials and checking their availability.
+This equivalence must use one shared resolution path rather than a second set
+of precedence rules.
+
+Structural resolution includes:
+
+- backend routing identity;
+- endpoint and model;
+- sampling, token, timeout, service-tier, and reasoning settings;
+- the effective credential environment-variable name or direct-key
+  requirement; and
+- deeply copied provider-specific extra parameters.
+
+Inspection returns the effective target rather than a raw profile definition.
+This keeps framework and backend defaults visible to consumers without
+creating a second public profile-loading interface.
+
+The result does not include request-override presence because no
+`ExecutionTargetOverride` participates in inspection.
+
+## Credentials And Sensitive Data
+
+Inspection reports credential requirements but never resolves, retains, or
+returns a credential value.
+
+The operation does not read the named environment variable and succeeds when
+that variable is absent or blank. It accepts neither a direct API key nor an
+API-key environment override. Consumers decide whether credential availability
+must be enforced during application configuration, while `Prepare`,
+`PrepareExecution`, `Run`, and `RunPrepared` retain their execution-time
+credential contracts.
+
+Error messages, formatting, and returned values must not expose environment
+values or other resolved secrets. Existing restrictions against raw API keys
+in profile sources remain unchanged.
+
+## Ownership, Consistency, And Concurrency
+
+Each successful call returns a caller-owned snapshot. Mutating the returned
+target or any nested extra-parameter map or slice cannot affect the engine,
+later inspection, or later execution.
+
+Inspection is safe to call concurrently under the engine's existing immutable
+registry and repository contracts. It does not mutate profile sources or
+cache a result globally.
+
+For filesystem-backed sources, an inspection describes the state observed by
+that call. It does not freeze the profile for a later `Run`; a source may
+change between operations. Consumers requiring an exact preflight-to-execution
+snapshot should use the existing prepared-execution workflow.
+
+## Errors And Cancellation
+
+The operation uses existing public error categories:
+
+- a blank profile ID matches `ErrInvalidRequest`;
+- an absent exact ID matches `ErrProfileNotFound` and not `ErrProfileLoad`;
+- read, decode, validation, and source-selection failures match
+  `ErrProfileLoad`; and
+- an unknown referenced backend or an invalid structurally resolved target
+  matches `ErrProfileLoad`.
+
+Errors should preserve useful underlying collaborator and context identities
+through `errors.Is` where the existing facade does so, without exposing
+internal package types. Context cancellation governs inspection and no partial
+inspection result is returned on failure.
+
+Missing credential values are not inspection errors. The operation cannot
+return capacity or model-generation failures because it performs neither
+backend admission nor generation.
+
+## Compatibility And Boundaries
+
+This feature is additive. Existing profile formats, source precedence,
+backend registration, `Prepare`, prepared execution, and `Run` behavior remain
+unchanged.
+
+The method belongs on the root `Engine` facade. Profile repositories and the
+backend registry remain internal implementation details, and no new public
+repository interface is introduced.
+
+Inspection does not require prompt lookup, rendering, artifact loading, schema
+loading, validation, backend-capacity admission, or model-client access.
+Engine construction retains its ordinary configuration requirements; this
+feature does not introduce a separate profile-only engine.
+
+## Documentation
+
+The completed documentation set has these ownership boundaries:
+
+- exported declarations and GoDoc own the exact method, result, ownership,
+  credential, error, and cancellation contracts;
+- the promptkit consumer guide explains configuration-time profile inspection
+  and distinguishes it from `Prepare` and prepared execution;
+- the profile format reference continues to own profile fields and source
+  precedence; and
+- internal documentation describes shared profile and target resolution
+  without duplicating public contracts.
+
+## Non-Goals
+
+This work does not include:
+
+- enumerating or searching profiles;
+- returning raw profile definitions or profile source paths;
+- accepting per-run execution overrides, direct API keys, or API-key
+  environment overrides;
+- checking environment-variable contents or other credential availability;
+- semantic execution-target fingerprints or profile hashes;
+- prompt-definition inspection or prompt default-profile resolution;
+- full-corpus validation across every profile source;
+- freezing a filesystem-backed profile for later execution;
+- exposing backend concurrency limits, queue state, or capacity policy;
+- model generation, provider health checks, or endpoint connectivity tests;
+- dynamic backend or profile registration after engine construction; or
+- changing current profile, backend, prepared-execution, or stable JSON
+  contracts.
+
+## Target End State
+
+After this work:
+
+- consumers can validate one configured profile without inventing a prompt or
+  placeholder inputs;
+- lookup observes ordinary programmatic, configured-source, and built-in
+  precedence;
+- a successful result proves that the profile exists, is valid, references a
+  registered backend when applicable, and resolves to a structurally valid
+  effective target;
+- the inspected target matches ordinary preparation for the same profile and
+  engine state before per-run overrides and credential availability checks;
+- credential requirements are visible without reading or exposing credential
+  values;
+- returned targets and nested data are caller-owned;
+- inspection performs no rendering, source loading unrelated to the profile,
+  capacity admission, or model work;
+- existing execution workflows and compatibility contracts remain unchanged;
+  and
+- Promptkit owns reusable profile validation while downstream applications
+  retain configuration policy, persistence, logging, and credential-timing
+  decisions.

docs/roadmap/weatherreporter-promptkit-wishlist.md

@@ -185,8 +185,8 @@ and move failures ahead of weather collection.
 
 ## Priority 3: Prompt-Independent Profile Inspection
 
-**Disposition:** Accepted into the
+**Disposition:** Covered by the accepted
-[future catalog](future.md#prompt-independent-profile-inspection).
+[prompt-independent profile inspection](profile-inspection.md) roadmap.
 
 ### Downstream need