Prepare the v0.10.0 release

Complete profile policy integration review
Document catalog profile compatibility
2026-09-22 14:06:35 +00:00 · 2026-09-22 12:33:29 +00:00 · 2026-09-22 12:31:50 +00:00 · 2026-09-22 12:26:22 +00:00 · 2026-09-22 12:23:07 +00:00 · 2026-09-22 12:17:41 +00:00
30 changed files with 1417 additions and 847 deletions
--- a/AGENTS.md
+++ b/AGENTS.md
@@ -1,2 +1,35 @@
 Please review `docs/development.md` for initial orientation in this repository
 and follow its task-specific reading guide.
+
+## Implementation Discipline
+
+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
+maintainability, not for the fewest lines, fewest options, or narrowest product
+surface.
+
+**Do not invent restrictions.** Do not reject, prohibit, constrain, cap,
+harden, or otherwise narrow behavior unless required by the user, an explicit
+repository contract, or an unavoidable correctness constraint. Preserve
+operator and caller choice where policy has not been established. If an
+additional restriction appears advisable, present it as a decision rather than
+silently implementing it.
+
+A correctness constraint must follow from the requested behavior or an
+established invariant, not from the convenience of the chosen implementation.
+Explain the specific failure it prevents and why a less restrictive
+implementation cannot satisfy the contract.
+
+**An implementation detail is not repository policy.** Tests and documentation
+must not elevate incidental behavior into a durable guarantee or restriction
+unless that behavior was expressly selected as part of the contract. Existing
+explicit contracts remain authoritative; changing or weakening one requires a
+deliberate decision rather than being inferred from this principle.
+
+Agent-authored plans, tests, documentation, and prior implementations are not
+evidence that an additional restriction was deliberately approved. Identify the
+authorizing requirement or decision; when that authority is unclear, surface
+the ambiguity rather than treating repetition as approval.
--- a/README.md
+++ b/README.md
@@ -33,6 +33,9 @@ boundary and constraints that framework work must preserve.

 ## Release Guidance

+Consumers upgrading to the `v0.10.0` profile-policy transition
+should read the [v0.10.0 transition guide](docs/releases/v0.10.0.md).
+
 Consumers upgrading from `v0.8.0` to `v0.9.0` should read the
 [v0.9.0 changelog and migration guide](docs/releases/v0.9.0.md).

--- a/backends.go
+++ b/backends.go
@@ -93,7 +93,7 @@ func WithBackend(backend Backend) Option {
 		queueCapacity = *backend.QueueCapacity
 	}
 	return optionFunc(func(options *engineOptions) error {
-		options.backends = append(options.backends, domain.Backend{
+		options.internal.AddBackend(domain.Backend{
 			ID:               backend.ID,
 			Endpoint:         backend.Endpoint,
 			APIKeyEnv:        backend.APIKeyEnv,
--- a/docs/consumers/pkg-promptkit.md
+++ b/docs/consumers/pkg-promptkit.md
@@ -232,6 +232,29 @@ For programmatic profiles,
 [`OpenAICompatibleProfile`](../../profiles.go) converts ordinary
 OpenAI-compatible settings into a value accepted by `WithProfiles`.

+### Choose A Profile Ownership Model
+
+Choose the profile source that matches the application's continuity needs:
+
+- Select `promptkit-openrouter-standard` or `promptkit-openrouter-auto` when
+  the maintained literal name is the desired consumer contract. Their current
+  selections are in the [format reference](../formats.md#built-in-profile-catalog).
+- Select an external catalog profile directly when the application accepts that
+  profile's catalog volatility. The selected external inventories are linked
+  from the [format reference](../formats.md#external-profile-inventories).
+- Define a complete application-owned profile with an explicit backend or
+  endpoint, model, and settings when the application owns those choices.
+
+An application profile that inherits an external base follows later changes to
+that base and fails if the base disappears; it is not a frozen copy. Promptkit
+tests the catalog versions selected in its module graph. Independently advancing
+a catalog dependency can remove an inherited base and produce an untested
+combination. Pinning the resolved module graph preserves the embedded data for
+a build, but cannot preserve provider availability. Running binaries neither
+download catalog updates nor automatically replace withdrawn models. See the
+[release policy](../release.md#catalog-profile-compatibility) for the exact
+cross-version guarantees.
+
 ### Alias A Built-In Profile

 Give an application-owned profile ID a built-in base when prompts should select
@@ -241,7 +264,7 @@ only the setting it owns:
 ```go
 promptkit.WithProfiles(promptkit.Profile{
 	ID:              "weather-light",
-	BaseProfileID:   "deepseek-4-flash",
+	BaseProfileID:   "promptkit-openrouter-standard",
 	ReasoningEffort: "high",
 })
 ```
@@ -250,7 +273,9 @@ Select `weather-light` in a prompt or `RunRequest.ProfileID`; it remains the
 reported selected profile. See the [profile inheritance format
 reference](../formats.md#profile-inheritance) and the
 [`Profile` GoDoc](../../types.go) for exact lookup, merging, and validation
-behavior.
+behavior. If the base is an external profile, apply the volatility guidance
+above when deciding whether to use an application-owned complete definition
+instead.

 ### Use The Rakestrawhome Built-In Profile

--- a/docs/development.md
+++ b/docs/development.md
@@ -34,7 +34,7 @@ Start with:
 | Root public API | The [architecture policy](policy/architecture.md), [consumer guide](consumers/pkg-promptkit.md), [testing policy](policy/testing.md), and existing GoDoc. |
 | Prompt, profile, or schema formats | The [framework format reference](formats.md), owning parser or validator package, and [documentation policy](policy/documentation.md). |
 | Source loading or validation | The [framework format reference](formats.md), [internal source document](internal/sources.md), and owning package tests. |
-| Maintained external catalogs or built-ins | The [internal source document](internal/sources.md), [framework format reference](formats.md), [testing policy](policy/testing.md), both catalog module repositories, and each catalog's release procedure. |
+| Maintained external catalogs or built-ins | The [internal source document](internal/sources.md), [framework format reference](formats.md), [testing policy](policy/testing.md), both catalog module repositories, each catalog's release procedure, and the selected module versions in `go.mod`. |
 | Model-client behavior | The [OpenAI-compatible integration contract](integrations/openai-compatible-chat.md), [internal model-client document](internal/llm.md), and owning package tests. |
 | Internal package implementation | The [architecture policy](policy/architecture.md), [internal component overview](internal/overview.md), and focused internal document listed for that package. |
 | Tests or test fixtures | The [testing policy](policy/testing.md), owning package, and focused internal document listed by the component overview. |
--- a/docs/formats.md
+++ b/docs/formats.md
@@ -283,7 +283,8 @@ Profile sources resolve matching IDs in this order:
 2. the ordinary configured source selected by a profile file, `fs.FS`, or
   configured profile directory;
 3. application fallback profiles supplied with `WithFallbackProfileFS`; and
-4. maintained external catalog profiles.
+4. Promptkit-owned profiles; and
+5. maintained external catalog profiles.

 A profile source supplies a complete definition; definitions and their fields
 are not merged across sources. A higher-precedence source falls back only when
@@ -326,33 +327,32 @@ that backend's connection and credential metadata. Profile files do not repeat
 those values. A configured, application fallback, or in-memory profile with
 the same profile ID takes precedence.

-| Provider | ID | Backend | Model |
-| --- | --- | --- | --- |
-| aion-labs | `aion-2` | `openrouter` | `aion-labs/aion-2.0` |
-| anthropic | `claude-fable-latest` | `openrouter` | `~anthropic/claude-fable-latest` |
-| anthropic | `claude-haiku-latest` | `openrouter` | `~anthropic/claude-haiku-latest` |
-| anthropic | `claude-opus-latest` | `openrouter` | `~anthropic/claude-opus-latest` |
-| anthropic | `claude-sonnet-latest` | `openrouter` | `~anthropic/claude-sonnet-latest` |
-| deepseek | `deepseek-3-2` | `openrouter` | `deepseek/deepseek-v3.2` |
-| deepseek | `deepseek-4-flash` | `openrouter` | `deepseek/deepseek-v4-flash` |
-| deepseek | `deepseek-4-pro` | `openrouter` | `deepseek/deepseek-v4-pro` |
-| google | `gemini-2-flash` | `openrouter` | `google/gemini-2.5-flash` |
-| google | `gemini-2-flash-lite` | `openrouter` | `google/gemini-2.5-flash-lite` |
-| google | `gemini-2-pro` | `openrouter` | `google/gemini-2.5-pro` |
-| google | `gemini-3-flash-lite` | `openrouter` | `google/gemini-3.1-flash-lite` |
-| google | `gemini-flash-latest` | `openrouter` | `~google/gemini-flash-latest` |
-| google | `gemini-pro-latest` | `openrouter` | `~google/gemini-pro-latest` |
-| google | `gemma-4-31b` | `openrouter` | `google/gemma-4-31b-it:exacto` |
-| google | `rakestrawhome-gemma-4-31b` | `rakestrawhome` | `google/gemma-4-31b-it` |
-| minimax | `minimax-m2` | `openrouter` | `minimax/minimax-m2.5` |
-| minimax | `minimax-m3` | `openrouter` | `minimax/minimax-m3` |
-| mistral | `mistral-large-2512` | `openrouter` | `mistralai/mistral-large-2512` |
-| mistral | `mistral-medium-3-5` | `openrouter` | `mistralai/mistral-medium-3-5` |
-| mistral | `mistral-small-3` | `openrouter` | `mistralai/mistral-small-3.2-24b-instruct` |
-| mistral | `mistral-small-4` | `openrouter` | `mistralai/mistral-small-2603` |
-| nvidia | `nemotron-3-ultra` | `openrouter` | `nvidia/nemotron-3-ultra-550b-a55b` |
-| openai | `gpt-5-mini` | `openrouter` | `openai/gpt-5.4-mini` |
-| openai | `gpt-5-nano` | `openrouter` | `openai/gpt-5.4-nano` |
+Promptkit owns two opt-in profiles. The following definitions are current
+selections, not automatic defaults:
+
+| ID | Current definition |
+| --- | --- |
+| `promptkit-openrouter-standard` | Inherits `gemini-flash-latest`. |
+| `promptkit-openrouter-auto` | Selects backend `openrouter` and model `openrouter/auto`. |
+
+Select either name through an existing request `profile_id` or prompt
+`default_profile`. Consumers can replace either definition or its inherited
+base through the ordinary profile-source precedence above. The
+[release policy](release.md#catalog-profile-compatibility) defines the
+cross-version guarantee for these names.
+
+## External Profile Inventories
+
+The external profile inventory is defined by the selected catalog modules, not
+duplicated here. Browse the exact data selected by this Promptkit version:
+
+- [OpenRouter catalog v2.20260922.1 profiles](https://gitea.maximumdirect.net/eric/promptkit-backend-openrouter/src/tag/v2.20260922.1/catalog/profiles)
+- [Rakestrawhome catalog v2.20260922.0 profiles](https://gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome/src/tag/v2.20260922.0/catalog/profiles)
+
+External profile entries are volatile across catalog releases. The
+[release policy](release.md#catalog-profile-compatibility) owns the precise
+compatibility boundary; a selected module version identifies tested local data,
+not live provider availability.

 ## Schemas

--- a/docs/internal/capacity.md
+++ b/docs/internal/capacity.md
@@ -14,7 +14,7 @@ stable JSON values.

 ## Construction And Pool Lifecycle

-Each root `NewEngine` call obtains a normalized capacity-policy snapshot from
+Each internal engine construction obtains a normalized capacity-policy snapshot from
 its immutable backend registry and constructs a new `Manager`. The manager
 creates one pool for each limited backend ID. It has no package-global mutable
 state, background workers, shutdown protocol, or persistence, so engines with
--- a/docs/internal/llm.md
+++ b/docs/internal/llm.md
@@ -10,7 +10,7 @@ owns the observable outbound HTTP contract. The
 [framework format reference](../formats.md) owns the profile and prompt
 settings consumed by the client.

-The concrete client remains under `internal/llm`. The root engine assembles it
+The concrete client remains under `internal/llm`. The internal engine assembles it
 as the default implementation behind Promptkit's public client boundary.

 ## Components And Flow
--- a/docs/internal/overview.md
+++ b/docs/internal/overview.md
@@ -11,25 +11,26 @@ contributor workflow and validation.

 | Component | Implemented responsibility | References |
 | --- | --- | --- |
-| Root `promptkit` package | Provides the supported engine facade, source, backend-registration, and injection options, public request, result, prompt-inspection, and profile-inspection values, opaque prepared-execution handles, profile construction, extension interfaces, value conversion, redacted formatting, typed capacity and generation error mapping, engine-local profile-source assembly including application fallbacks, and bounded output-repair assembly. | [Package GoDoc](../../doc.go), [prepared execution](../../prepared_execution.go), [backend API](../../backends.go), [engine assembly](../../engine.go) |
+| Root `promptkit` package | Provides the supported engine facade, source, backend-registration, and injection options, public request, result, prompt-inspection, and profile-inspection values, opaque prepared-execution handles, profile construction, extension interfaces, value conversion, redacted formatting, and typed capacity and generation error mapping. | [Package GoDoc](../../doc.go), [prepared execution](../../prepared_execution.go), [backend API](../../backends.go), [engine facade](../../engine.go) |
 | `examples/go-library/prepare` | Demonstrates an offline downstream consumer using a prompt file, in-memory profile, inline input, and `Prepare`. It is not a public library package. | [Example program](../../examples/go-library/prepare/main.go) |
 | `examples/go-library/run` | Demonstrates an offline downstream consumer using a prompt file, in-memory profile, inline input, an injected deterministic model client, and `Run`. It is not a public library package. | [Example program](../../examples/go-library/run/main.go) |
 | `internal/backend` | Constructs each engine's immutable registry from maintained definitions and consumer additions, validates and defensively copies definitions through the shared JSON-value package, and consumes the LLM-owned OpenAI-compatible reserved request-field rule. | [Backend registry](../../internal/backend/registry.go) |
 | `internal/catalog` | Strictly validates imported immutable maintained backend and profile catalog assets before engine assembly uses them. | [Catalog adapter](../../internal/catalog/catalog.go), [internal sources](sources.md#profiles-and-built-ins) |
 | `internal/capacity` | Owns engine-local bounded execution admission and FIFO model-generation permits for limited backend IDs, including cancellation-safe waiter removal and client wrapping. | [Internal capacity management](capacity.md) |
 | `internal/domain` | Defines internal framework values for requests, artifacts, prompt definitions, profiles, execution targets, rendering, generation, and validation, and owns source-neutral invariants for shared execution settings, OpenAI-compatible base endpoints, session identifiers, and output contracts. Source parsing, required fields, other source-specific normalization, defaulting, and boundary-specific error classification remain with their callers. | [Domain declarations](../../internal/domain/domain.go), [endpoint invariant](../../internal/domain/endpoint.go) |
+| `internal/engine` | Assembles external catalogs, Promptkit-owned profiles, repositories, registry, capacity, collaborators, repairer, and the one use-case runner for each engine instance. | [Engine assembly](../../internal/engine/engine.go), [internal sources](sources.md#profiles-and-built-ins), [internal runner](runner.md) |
 | `internal/defaults` | Defines application-neutral framework constants and constructs the default execution target. It contains no CLI, server, or inbound HTTP limits. | [Framework defaults](../../internal/defaults/defaults.go) |
 | `internal/filecatalog` | Provides deterministic YAML discovery and path helpers for operating-system filesystems and `fs.FS` sources. | [File catalog](../../internal/filecatalog/catalog.go) |
 | `internal/jsonvalue` | Validates and deeply copies bounded JSON-compatible extra-parameter and prepared-schema trees while preserving supported concrete value types and rejecting cycles or excessive depth and work. | [JSON values](../../internal/jsonvalue/jsonvalue.go) |
 | `internal/promptdef` | Loads strictly decoded, validated prompt definitions from filesystem and `fs.FS` sources, including version selection and contained file-backed message content. | [Framework formats](../formats.md), [prompt-definition repository](../../internal/promptdef/filesystem_repository.go) |
-| `internal/profile` | Loads strictly decoded, locally validated execution profiles from filesystem and `fs.FS` sources, overlays raw sources with error-preserving fallback, and resolves inherited profiles. | [Framework formats](../formats.md), [profile repositories](../../internal/profile/filesystem_repository.go), [internal sources](sources.md#profiles-and-built-ins) |
+| `internal/profile` | Owns immutable in-memory and filesystem profile repositories, local profile validation, raw-source overlays with error-preserving fallback, and inherited-profile resolution. | [Framework formats](../formats.md), [profile repositories](../../internal/profile/filesystem_repository.go), [internal sources](sources.md#profiles-and-built-ins) |
 | `internal/prompt` | Renders prompt messages from Go templates with artifact, variable, session, and cache-control data. | [Go-template renderer](../../internal/prompt/go_renderer.go) |
 | `internal/artifact` | Resolves ordinary inline and unrestricted caller-selected file references into copied artifacts with metadata and hashes. | [Internal sources and validation](sources.md) |
 | `internal/validate` | Validates basic, JSON, and JSON Schema output using operating-system filesystem or `fs.FS` schema sources and creates operation-local validation plans with canonical contained schema resources. | [Framework formats](../formats.md#schemas), [internal sources and validation](sources.md) |
 | `internal/llm` | Defines the internal generation boundary and implements outbound OpenAI-compatible chat requests from resolved execution targets, including bounded structured non-success response decoding, successful-response decoding, authentication, deadline handling, and ownership of the OpenAI-compatible reserved request-field policy. | [Internal model client](llm.md) |
 | `internal/usecase` | Resolves prompt definitions and hashes, profiles, backends, and targets for exact inspection and request settings for preparation, and coordinates ordinary execution and one-attempt prepared execution across internal sources, rendering, artifact loading, operation-local validation plans, generation, capacity, and bounded repair. | [Internal runner](runner.md), [prepared-execution implementation](../../internal/usecase/prepared_execution.go) |

-The root package assembles these internal components without exposing their
+The internal engine assembles these internal components without exposing their
 representations. Consumers depend only on the root facade.

 ## Maintenance
--- a/docs/internal/runner.md
+++ b/docs/internal/runner.md
@@ -9,8 +9,8 @@ artifact, rendering, and validation behavior, while the
 [model-client document](llm.md) owns generation behavior and failure
 categories.

-The runner remains under `internal/usecase` and is assembled by the root
-Promptkit engine. Its concrete type is not part of the public API.
+The runner remains under `internal/usecase` and is assembled by
+`internal/engine`. Its concrete type is not part of the public API.
 The [framework format reference](../formats.md) owns prompt, profile, schema,
 and override semantics consumed by the runner.

@@ -18,12 +18,12 @@ and override semantics consumed by the runner.

 `Runner` coordinates narrow internal interfaces for prompt definitions,
 profiles, backend resolution, artifacts, rendering, model generation, and
-validation. The root engine supplies one immutable registry containing the
+validation. The internal engine supplies one immutable registry containing the
 built-in backend and validated consumer additions, one engine-local run
 admitter, and a model client wrapped by the same capacity manager. Validation
 plans and provider-facing schema metadata come from the validator's preparation
 interface.
-The root engine supplies one default output repairer through the explicit
+The internal engine supplies one default output repairer through the explicit
 runner constructor, using the same capacity-wrapped client as initial
 generation. The no-repair runner constructor remains available for focused
 internal callers and tests.
--- a/docs/internal/sources.md
+++ b/docs/internal/sources.md
@@ -6,7 +6,7 @@ This document describes Promptkit's implemented internal source, artifact,
 rendering, and output-validation behavior. The
 [architecture policy](../policy/architecture.md) owns the library boundary and
 dependency rules. None of these internal packages is a supported consumer API,
-and the root engine assembles them behind its public source options and values.
+and the internal engine assembles them behind the public facade's source options and values.
 The [framework format reference](../formats.md) owns the exact file fields,
 validation modes, built-in catalog, and source precedence.

@@ -45,8 +45,10 @@ duplicate detection, and source containment:

 ## Profiles And Built-Ins

-`internal/profile` loads, locally validates, overlays, and resolves execution
-profiles from an operating-system filesystem or an `fs.FS`. A file contains
+`internal/profile` owns immutable in-memory and filesystem repositories, local
+validation, overlays, and resolution for execution profiles. In-memory
+definitions are normalized and validated once at that repository boundary and
+are defensively copied on storage and lookup. A file contains
 exactly one YAML document and its trimmed YAML `id` is its only selection
 identity; filenames do not confer authority. Each point lookup reads discovered
 files once for their metadata and reuses the selected file's bytes for strict
@@ -67,8 +69,12 @@ repositories described above.
 `internal/catalog` validates the imported immutable OpenRouter and
 Rakestrawhome asset modules as one private adapter boundary. It enforces their
 manifest, layout, profile ownership, inheritance, and secret-safety rules
-before returning raw catalog sources. Root assembly uses those validated
-catalogs as the maintained lowest-precedence profile source.
+before returning raw catalog sources. Internal engine assembly uses those validated
+catalogs as the lowest-precedence profile source.
+
+Normalized external catalog profile IDs with the exact `promptkit-` prefix are
+rejected at this adapter boundary. That reservation applies only to imported
+catalogs; configured consumer sources retain the ordinary profile-ID rules.

 The overlay repository consults the next repository only when the
 higher-precedence repository reports that a profile is absent. A reliably
@@ -78,12 +84,15 @@ backend registry membership because the available registry belongs to the
 assembled engine; the runner checks membership during preparation and exact
 profile inspection.

-The root engine assembles one raw composite catalog in precedence order:
+The internal engine assembles one raw composite catalog in precedence order:
 in-memory profiles, one ordinary configured source, an application fallback
-source, then the maintained external catalog. An explicit file or `fs.FS` profile
-source replaces `Config.ProfileDir` within the ordinary configured-source
-category. One outer resolving repository wraps that complete raw catalog, so
-each base lookup observes the same precedence and shadowing rules.
+source, Promptkit-owned profiles, then the maintained external catalog. It
+constructs the owned definitions through the in-memory repository and validates
+their maintained-only resolution and backend membership before consumer sources
+are overlaid. An explicit file or `fs.FS` profile source replaces
+`Config.ProfileDir` within the ordinary configured-source category. One outer
+resolving repository wraps that complete raw catalog, so each base lookup
+observes the same precedence and shadowing rules.

 The resolving repository traverses every selected chain afresh, retains no
 cache, detects cycles, limits a chain to 32 profiles, merges root-to-leaf into a
@@ -98,9 +107,10 @@ or schema sources. It does not retain that lookup for a later execution.
 Prepared execution instead freezes the fully resolved target; a later ordinary
 operation performs a fresh traversal.

-The maintained external catalog provides every built-in profile and its
-matching backend definition. Profile loading and overlay behavior are owned by the
-[profile repository tests](../../internal/profile/repository_test.go), while
+The imported external catalog provides external profiles and matching backend
+definitions. The internal engine owns the Promptkit profiles documented in the
+[framework format reference](../formats.md#built-in-profile-catalog). Profile
+loading and overlay behavior are owned by the [profile repository tests](../../internal/profile/repository_test.go), while
 catalog completeness, backend selection, and duplicate IDs are owned by the
 [catalog adapter tests](../../internal/catalog/catalog_test.go).

--- a/docs/policy/architecture.md
+++ b/docs/policy/architecture.md
@@ -30,7 +30,8 @@ The implemented internal components consist of:
 - `internal/filecatalog`, which discovers YAML files and provides source-path
  helpers for filesystem and `fs.FS` consumers;
 - `internal/catalog`, which validates immutable external maintained-catalog
-  assets before they are eligible for engine assembly;
+  assets and their reserved profile namespace before they are eligible for
+  engine assembly;
 - `internal/jsonvalue`, which validates and defensively copies JSON-compatible
  extra-parameter trees;
 - `internal/promptdef`, which loads and validates prompt definitions from
@@ -46,26 +47,28 @@ The implemented internal components consist of:
  implements outbound OpenAI-compatible chat requests; and
 - `internal/usecase`, which coordinates preparation and execution across the
  internal framework components.
+- `internal/engine`, which assembles those components into one engine and
+  delegates execution to the use-case runner.

 The `examples/go-library/prepare` and `examples/go-library/run` packages are
 maintained downstream consumers of the root facade. They do not expose library
 packages or participate in internal assembly.

-The root facade assembles one immutable backend registry, one capacity manager,
+The internal engine assembles one immutable backend registry, one capacity manager,
 the internal repositories, renderer, validator, outbound client, and use-case
-runner while translating public values and errors at the library boundary. The
-registry contains validated maintained definitions plus engine-scoped consumer
-additions.
-The facade constructs the capacity manager from the registry's immutable
+runner. The registry contains validated maintained definitions plus engine-scoped
+consumer additions. The root facade translates public values and errors at the
+library boundary.
+The internal engine constructs the capacity manager from the registry's immutable
 policy snapshot, wraps the selected built-in or injected model client, and
 supplies bounded admission to the runner. The defaults and renderer depend on
 the domain model. Prompt-definition and profile repositories use the domain
 model, file catalog, and YAML decoder. The catalog adapter validates imported
-immutable maintained data before root assembly supplies it to the profile
-package. Artifact reading uses the domain
-model and application-neutral defaults. Validation uses the domain model, file
-catalog, and JSON Schema implementation. The model client uses the domain
-model, application-neutral defaults, and an injected or standard-library HTTP
+immutable maintained data, including its reserved namespace, before internal
+engine assembly supplies it to the profile package. Artifact reading uses the
+domain model and application-neutral defaults. Validation uses the domain model,
+file catalog, and JSON Schema implementation. The model client uses the domain
+model and application-neutral defaults, and an injected or standard-library HTTP
 client. The use-case runner depends on the narrow interfaces owned by each
 internal component, including backend lookup and run admission.

@@ -127,8 +130,10 @@ consumer contract requires a public package.
 Each package must have one cohesive responsibility and a clear dependency
 direction. Internal packages must not expose their types merely to simplify
 wiring, and the public facade must not leak internal representations through
-exported signatures. New public packages require a durable consumer need that
-cannot be served cleanly by the root facade.
+exported signatures. Production packages under `internal/` must not import the
+module root; the root facade may depend on internal implementation packages.
+New public packages require a durable consumer need that cannot be served
+cleanly by the root facade.

 The [internal component overview](../internal/overview.md) must be updated as
 packages are implemented or their responsibilities change.
--- a/docs/release.md
+++ b/docs/release.md
@@ -16,6 +16,32 @@ changes, and state any action required of consumers.
 Promptkit releases are source-only. The annotated tag message is the release
 note; there is no separate hosted release or binary packaging step.

+## Catalog Profile Compatibility
+
+External catalog profile data may be added, removed, renamed, or modified
+without deprecation or advance notice. This exception is limited to profile
+data imported from the maintained catalog modules. It does not weaken ordinary
+compatibility for Promptkit's public Go API, configuration and format semantics,
+runtime behavior, catalog-module APIs, manifest schema, backend definitions, or
+consumer-owned definitions.
+
+Within the catalog versions selected and tested by a Promptkit release, and
+unless a consumer overrides the name or its base, Promptkit keeps the literal
+profile IDs `promptkit-openrouter-standard` and
+`promptkit-openrouter-auto` available. The names do not promise a permanent
+model, backend, routing behavior, settings, cost, output, or upstream
+availability. The [framework format reference](formats.md#built-in-profile-catalog)
+owns their current definitions.
+
+`v0.10.0` is the initial minor release for this compatibility transition.
+Afterward, catalog-only updates and adjustments to the current selections may
+ship in a patch release when all other compatibility obligations remain intact.
+External profile removals can require consumer action; they are not automatic
+migrations.
+
+Catalog adoption and release validation remain local and offline. They do not
+probe provider endpoints, request model lists, or make inference calls.
+
 ## Establish The Candidate

 Choose a version that has not been published and export it as
@@ -147,11 +173,12 @@ Inspect the complete message and confirm that it accurately records the
 compatibility impact, public API changes, and required consumer action.

 When a release introduces or updates the maintained external catalogs, state
-that it selects two independently versioned data dependencies, preserves the
-public API and configuration, requires no consumer migration, and guarantees
-only the catalog versions selected and tested by that Promptkit release. Link
-to the current architecture and format documentation rather than duplicating
-catalog contracts in the release note.
+the two independently versioned selected data dependencies and any resulting
+consumer action. State that external profile additions, removals, renames, and
+selection changes are covered by the catalog-profile policy, while the ordinary
+public API and configuration contracts remain in force. Link to the current
+format and consumer documentation rather than duplicating catalog inventories
+or contracts in the release note.

 ## Create And Inspect The Tag

--- a/docs/releases/v0.10.0.md
+++ b/docs/releases/v0.10.0.md
@@ -0,0 +1,44 @@
+# Promptkit v0.10.0
+
+This supplemental guide summarizes the `v0.10.0` changes and migration needs.
+The annotated tag remains the authoritative release record.
+
+## Transition Summary
+
+`v0.10.0` adopts independently versioned OpenRouter and Rakestrawhome catalog
+modules whose external profile data can change between catalog releases. It
+also introduces the maintained literal names
+`promptkit-openrouter-standard` and `promptkit-openrouter-auto`.
+
+The public package now delegates assembly to an internal engine while retaining
+the existing Go API. This refactor requires no consumer code changes.
+
+This release selects OpenRouter `v2.20260922.1` and Rakestrawhome
+`v2.20260922.0`; their exact inventories are linked from the
+[format reference](../formats.md#external-profile-inventories).
+
+The maintained names provide continuity only within the catalog versions
+selected and tested by a Promptkit release and when consumers do not override
+the name or its base. Their current selections may change. External catalog
+profile IDs can be removed, renamed, or modified, so an application that
+selects one directly may need to update its configuration when upgrading.
+
+## Consumer Migration
+
+Before upgrading, review every profile ID used by prompts, requests, and
+application-owned inheritance. Choose a maintained name, accept an external
+catalog profile's volatility, or define a complete application-owned profile
+when the application must control its target and settings. An alias that
+inherits from an external base is not a frozen copy.
+
+In particular, the selected OpenRouter catalog removes `deepseek-3-2`,
+`deepseek-4-flash`, and `deepseek-4-pro`. Consumers using those IDs must choose
+an available profile or supply their own complete definition; the new
+`deepseek-flash-latest` and `deepseek-pro-latest` profiles are not automatic
+aliases and need not preserve the previous settings.
+
+See the [release policy](../release.md#catalog-profile-compatibility) for the
+compatibility boundary, the [format reference](../formats.md#built-in-profile-catalog)
+for current Promptkit-owned definitions and selected external inventories, and
+the [consumer guide](../consumers/pkg-promptkit.md#choose-a-profile-ownership-model)
+for configuration choices.
--- a/engine.go
+++ b/engine.go
@@ -6,25 +6,11 @@ import (
 	"fmt"
 	"io/fs"
 	"net/http"
-	"os"
-	"path/filepath"
-	"strings"
 	"time"

-	openrouter "gitea.maximumdirect.net/eric/promptkit-backend-openrouter"
-	rakestrawhome "gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome"
-	artifactadapter "gitea.maximumdirect.net/eric/promptkit/internal/artifact"
-	"gitea.maximumdirect.net/eric/promptkit/internal/backend"
-	"gitea.maximumdirect.net/eric/promptkit/internal/capacity"
-	"gitea.maximumdirect.net/eric/promptkit/internal/catalog"
-	"gitea.maximumdirect.net/eric/promptkit/internal/defaults"
 	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
-	"gitea.maximumdirect.net/eric/promptkit/internal/llm"
-	"gitea.maximumdirect.net/eric/promptkit/internal/profile"
-	"gitea.maximumdirect.net/eric/promptkit/internal/prompt"
-	"gitea.maximumdirect.net/eric/promptkit/internal/promptdef"
+	internalengine "gitea.maximumdirect.net/eric/promptkit/internal/engine"
 	"gitea.maximumdirect.net/eric/promptkit/internal/usecase"
-	"gitea.maximumdirect.net/eric/promptkit/internal/validate"
 )

 // ErrInvalidConfig identifies invalid engine construction, including missing
@@ -91,7 +77,7 @@ var (
 // model generation. Injected collaborators may still be invoked concurrently
 // across different backend pools or for unlimited backends.
 type Engine struct {
-	runner *usecase.Runner
+	internal *internalengine.Engine
 }

 // Config selects the directory-backed sources and built-in model-client
@@ -140,20 +126,7 @@ func (f optionFunc) apply(options *engineOptions) error {
 }

 type engineOptions struct {
-	llmClient             llm.Client
-	artifactReader        artifactadapter.Reader
-	promptDefs            promptdef.Repository
-	profiles              profile.Repository
-	fallbackProfiles      profile.Repository
-	memoryProfiles        profile.Repository
-	backends              []domain.Backend
-	validator             validate.Validator
-	promptSource          bool
-	profileSource         bool
-	fallbackProfileSource bool
-	memorySource          bool
-	validatorSource       bool
-	artifactSource        bool
+	internal internalengine.Options
 }

 // WithLLMClient replaces the built-in model client used by [Engine.Run] and
@@ -169,7 +142,7 @@ func WithLLMClient(client LLMClient) Option {
 		if client == nil {
 			return ErrInvalidConfig
 		}
-		options.llmClient = publicLLMClientAdapter{client: client}
+		options.internal.SetLLMClient(publicLLMClientAdapter{client: client})
 		return nil
 	})
 }
@@ -184,8 +157,7 @@ func WithArtifactReader(reader ArtifactReader) Option {
 		if reader == nil {
 			return ErrInvalidConfig
 		}
-		options.artifactReader = publicArtifactReaderAdapter{reader: reader}
-		options.artifactSource = true
+		options.internal.SetArtifactReader(publicArtifactReaderAdapter{reader: reader})
 		return nil
 	})
 }
@@ -199,15 +171,7 @@ func WithArtifactReader(reader ArtifactReader) Option {
 // prompt-source options.
 func WithPromptFS(fsys fs.FS, root string) Option {
 	return optionFunc(func(options *engineOptions) error {
-		if fsys == nil {
-			return ErrInvalidConfig
-		}
-		if strings.TrimSpace(root) == "" {
-			return ErrInvalidConfig
-		}
-		options.promptDefs = promptdef.NewFSRepository(fsys, root)
-		options.promptSource = true
-		return nil
+		return options.internal.SetPromptFS(fsys, root)
 	})
 }

@@ -218,13 +182,7 @@ func WithPromptFS(fsys fs.FS, root string) Option {
 // This option replaces Config.PromptDir and earlier prompt-source options.
 func WithPromptFile(path string) Option {
 	return optionFunc(func(options *engineOptions) error {
-		fsys, root, err := fileSource(path)
-		if err != nil {
-			return err
-		}
-		options.promptDefs = promptdef.NewFileRepository(fsys, root, filepath.Dir(path))
-		options.promptSource = true
-		return nil
+		return options.internal.SetPromptFile(path)
 	})
 }

@@ -238,15 +196,7 @@ func WithPromptFile(path string) Option {
 // FS profile-source options, but remains below WithProfiles in precedence.
 func WithProfileFS(fsys fs.FS, root string) Option {
 	return optionFunc(func(options *engineOptions) error {
-		if fsys == nil {
-			return ErrInvalidConfig
-		}
-		if strings.TrimSpace(root) == "" {
-			return ErrInvalidConfig
-		}
-		options.profiles = profile.NewFSRepository(fsys, root)
-		options.profileSource = true
-		return nil
+		return options.internal.SetProfileFS(fsys, root)
 	})
 }

@@ -260,13 +210,7 @@ func WithProfileFS(fsys fs.FS, root string) Option {
 // precedence.
 func WithProfileFile(path string) Option {
 	return optionFunc(func(options *engineOptions) error {
-		fsys, root, err := fileSource(path)
-		if err != nil {
-			return err
-		}
-		options.profiles = profile.NewFSRepository(fsys, root)
-		options.profileSource = true
-		return nil
+		return options.internal.SetProfileFile(path)
 	})
 }

@@ -291,15 +235,7 @@ func WithProfileFile(path string) Option {
 // failover.
 func WithFallbackProfileFS(fsys fs.FS, root string) Option {
 	return optionFunc(func(options *engineOptions) error {
-		if fsys == nil {
-			return ErrInvalidConfig
-		}
-		if strings.TrimSpace(root) == "" {
-			return ErrInvalidConfig
-		}
-		options.fallbackProfiles = profile.NewFSRepository(fsys, root)
-		options.fallbackProfileSource = true
-		return nil
+		return options.internal.SetFallbackProfileFS(fsys, root)
 	})
 }

@@ -314,13 +250,11 @@ func WithFallbackProfileFS(fsys fs.FS, root string) Option {
 // earlier in-memory set rather than merging it.
 func WithProfiles(profiles ...Profile) Option {
 	return optionFunc(func(options *engineOptions) error {
-		repo, err := newMemoryProfileRepository(profiles)
-		if err != nil {
-			return err
+		definitions := make([]domain.ExecutionProfile, len(profiles))
+		for index, publicProfile := range profiles {
+			definitions[index] = toDomainProfile(publicProfile)
 		}
-		options.memoryProfiles = repo
-		options.memorySource = true
-		return nil
+		return options.internal.SetMemoryProfiles(definitions)
 	})
 }

@@ -332,15 +266,7 @@ func WithProfiles(profiles ...Profile) Option {
 // replaces Config.SchemaDir and earlier schema-source options.
 func WithSchemaFS(fsys fs.FS, root string) Option {
 	return optionFunc(func(options *engineOptions) error {
-		if fsys == nil {
-			return ErrInvalidConfig
-		}
-		if strings.TrimSpace(root) == "" {
-			return ErrInvalidConfig
-		}
-		options.validator = validate.NewFSValidator(fsys, root)
-		options.validatorSource = true
-		return nil
+		return options.internal.SetSchemaFS(fsys, root)
 	})
 }

@@ -351,13 +277,7 @@ func WithSchemaFS(fsys fs.FS, root string) Option {
 // replaces Config.SchemaDir and earlier schema-source options.
 func WithSchemaFile(path string) Option {
 	return optionFunc(func(options *engineOptions) error {
-		fsys, root, err := fileSource(path)
-		if err != nil {
-			return err
-		}
-		options.validator = validate.NewFSValidator(fsys, root)
-		options.validatorSource = true
-		return nil
+		return options.internal.SetSchemaFile(path)
 	})
 }

@@ -384,113 +304,14 @@ func NewEngine(cfg Config, opts ...Option) (*Engine, error) {
 		}
 	}

-	promptDefs := options.promptDefs
-	if !options.promptSource {
-		if strings.TrimSpace(cfg.PromptDir) == "" {
-			return nil, fmt.Errorf("%w: prompt directory is required", ErrInvalidConfig)
-		}
-		promptDefs = promptdef.NewFilesystemRepository(cfg.PromptDir)
-	}
-
-	maintainedCatalogs, err := catalog.Load(
-		catalog.Source{Name: "OpenRouter", ExpectedBackendID: backend.OpenRouterID, FS: openrouter.FS(), Root: openrouter.Root},
-		catalog.Source{Name: "Rakestrawhome", ExpectedBackendID: backend.RakestrawHomeID, FS: rakestrawhome.FS(), Root: rakestrawhome.Root},
+	assembled, err := internalengine.New(
+		internalengine.Config{PromptDir: cfg.PromptDir, ProfileDir: cfg.ProfileDir, SchemaDir: cfg.SchemaDir, Timeout: cfg.Timeout, HTTPClient: cfg.HTTPClient},
+		options.internal,
 	)
 	if err != nil {
-		return nil, fmt.Errorf("%w: failed to load maintained catalogs: %v", ErrInvalidConfig, err)
+		return nil, fmt.Errorf("%w: %v", ErrInvalidConfig, err)
 	}
-
-	profiles := newProfileRepository(cfg.ProfileDir, options, maintainedCatalogs.Profiles)
-
-	backendRegistry, err := backend.NewRegistry(maintainedCatalogs.Backends, options.backends)
-	if err != nil {
-		return nil, fmt.Errorf("%w: failed to construct backend registry: %v", ErrInvalidConfig, err)
-	}
-
-	capacityManager, err := capacity.NewManager(backendRegistry.CapacityPolicies())
-	if err != nil {
-		return nil, fmt.Errorf("%w: failed to construct backend capacity manager: %v", ErrInvalidConfig, err)
-	}
-
-	validator := options.validator
-	if !options.validatorSource {
-		schemaDir := cfg.SchemaDir
-		if strings.TrimSpace(schemaDir) == "" {
-			schemaDir = defaults.SchemaDirDefault
-		}
-		validator = validate.NewStandardValidator(schemaDir)
-	}
-
-	llmClient := options.llmClient
-	if llmClient == nil {
-		var err error
-		llmClient, err = llm.NewOpenAICompatibleClient(llm.OpenAICompatibleConfig{
-			Timeout:    cfg.Timeout,
-			HTTPClient: cfg.HTTPClient,
-		})
-		if err != nil {
-			return nil, fmt.Errorf("%w: %v", ErrInvalidConfig, err)
-		}
-	}
-	llmClient = capacity.NewClient(capacityManager, llmClient)
-
-	artifacts := options.artifactReader
-	if !options.artifactSource {
-		artifacts = artifactadapter.NewCompositeReader()
-	}
-
-	return &Engine{
-		runner: usecase.NewRunnerWithRepairer(
-			promptDefs,
-			profiles,
-			backendRegistry,
-			artifacts,
-			prompt.NewGoRenderer(),
-			llmClient,
-			validator,
-			usecase.NewDefaultOutputRepairer(llmClient),
-			capacityManager,
-		),
-	}, nil
-}
-
-func newProfileRepository(profileDir string, options engineOptions, maintained profile.Repository) profile.Repository {
-	repository := maintained
-
-	if options.fallbackProfileSource {
-		repository = profile.NewOverlayRepository(options.fallbackProfiles, repository)
-	}
-
-	if options.profileSource {
-		repository = profile.NewOverlayRepository(options.profiles, repository)
-	} else if strings.TrimSpace(profileDir) != "" {
-		repository = profile.NewOverlayRepository(profile.NewFilesystemRepository(profileDir), repository)
-	}
-
-	if options.memorySource {
-		repository = profile.NewOverlayRepository(options.memoryProfiles, repository)
-	}
-
-	return profile.NewResolvingRepository(repository)
-}
-
-func fileSource(name string) (fs.FS, string, error) {
-	if strings.TrimSpace(name) == "" {
-		return nil, "", ErrInvalidConfig
-	}
-	dir := filepath.Dir(name)
-	base := filepath.Base(name)
-	if base == "." || base == string(filepath.Separator) {
-		return nil, "", ErrInvalidConfig
-	}
-	info, err := os.Stat(name)
-	if err != nil {
-		return nil, "", fmt.Errorf("%w: failed to access source file %q: %v", ErrInvalidConfig, name, err)
-	}
-	if info.IsDir() {
-		return nil, "", fmt.Errorf("%w: source path %q must be a file", ErrInvalidConfig, name)
-	}
-	return os.DirFS(dir), filepath.ToSlash(base), nil
+	return &Engine{internal: assembled}, nil
 }

 // InspectPrompt resolves one explicit prompt definition without selecting a
@@ -529,11 +350,11 @@ func (e *Engine) InspectPrompt(
 	promptID string,
 	promptVersion string,
 ) (*PromptInspection, error) {
-	if e == nil || e.runner == nil {
+	if e == nil || e.internal == nil {
 		return nil, fmt.Errorf("%w: engine is nil", ErrInvalidConfig)
 	}

-	inspection, err := e.runner.InspectPrompt(ctx, promptID, promptVersion)
+	inspection, err := e.internal.InspectPrompt(ctx, promptID, promptVersion)
 	if err != nil {
 		return nil, mapPublicError(err)
 	}
@@ -569,11 +390,11 @@ func (e *Engine) InspectPrompt(
 // profile loading matches ErrProfileLoad while preserving the context error.
 // InspectProfile returns no partial result on error.
 func (e *Engine) InspectProfile(ctx context.Context, profileID string) (*ProfileInspection, error) {
-	if e == nil || e.runner == nil {
+	if e == nil || e.internal == nil {
 		return nil, fmt.Errorf("%w: engine is nil", ErrInvalidConfig)
 	}

-	inspection, err := e.runner.InspectProfile(ctx, profileID)
+	inspection, err := e.internal.InspectProfile(ctx, profileID)
 	if err != nil {
 		return nil, mapPublicError(err)
 	}
@@ -600,7 +421,7 @@ func (e *Engine) InspectProfile(ctx context.Context, profileID string) (*Profile
 // relationship to ctx.Err is promised. Prepare returns no partial result on
 // error.
 func (e *Engine) Prepare(ctx context.Context, req RunRequest) (*PreparedRun, error) {
-	if e == nil || e.runner == nil {
+	if e == nil || e.internal == nil {
 		return nil, fmt.Errorf("%w: engine is nil", ErrInvalidConfig)
 	}

@@ -609,7 +430,7 @@ func (e *Engine) Prepare(ctx context.Context, req RunRequest) (*PreparedRun, err
 		return nil, fmt.Errorf("%w: %v", ErrInvalidRequest, err)
 	}

-	prepared, err := e.runner.Prepare(ctx, domainReq)
+	prepared, err := e.internal.Prepare(ctx, domainReq)
 	if err != nil {
 		return nil, mapPublicError(err)
 	}
@@ -633,7 +454,7 @@ func (e *Engine) Prepare(ctx context.Context, req RunRequest) (*PreparedRun, err
 // returns no handle on error. A nil Engine returns an error matching
 // ErrInvalidConfig.
 func (e *Engine) PrepareExecution(ctx context.Context, req RunRequest) (*PreparedExecution, error) {
-	if e == nil || e.runner == nil {
+	if e == nil || e.internal == nil {
 		return nil, fmt.Errorf("%w: engine is nil", ErrInvalidConfig)
 	}

@@ -642,7 +463,7 @@ func (e *Engine) PrepareExecution(ctx context.Context, req RunRequest) (*Prepare
 		return nil, fmt.Errorf("%w: %v", ErrInvalidRequest, err)
 	}

-	prepared, err := e.runner.PrepareExecution(ctx, domainReq)
+	prepared, err := e.internal.PrepareExecution(ctx, domainReq)
 	if err != nil {
 		return nil, mapPublicError(err)
 	}
@@ -674,7 +495,7 @@ func (e *Engine) PrepareExecution(ctx context.Context, req RunRequest) (*Prepare
 // behavior. A nil Engine returns ErrInvalidConfig. Run returns no partial
 // result on error.
 func (e *Engine) Run(ctx context.Context, req RunRequest) (*RunResult, error) {
-	if e == nil || e.runner == nil {
+	if e == nil || e.internal == nil {
 		return nil, fmt.Errorf("%w: engine is nil", ErrInvalidConfig)
 	}

@@ -683,7 +504,7 @@ func (e *Engine) Run(ctx context.Context, req RunRequest) (*RunResult, error) {
 		return nil, fmt.Errorf("%w: %v", ErrInvalidRequest, err)
 	}

-	result, err := e.runner.Run(ctx, domainReq)
+	result, err := e.internal.Run(ctx, domainReq)
 	if err != nil {
 		return nil, mapPublicError(err)
 	}
@@ -715,7 +536,7 @@ func (e *Engine) Run(ctx context.Context, req RunRequest) (*RunResult, error) {
 // including repair exhaustion, is returned in RunResult, not as an operational
 // error. An operational error returns no partial RunResult.
 func (e *Engine) RunPrepared(ctx context.Context, prepared *PreparedExecution) (*RunResult, error) {
-	if e == nil || e.runner == nil {
+	if e == nil || e.internal == nil {
 		return nil, fmt.Errorf("%w: engine is nil", ErrInvalidConfig)
 	}

@@ -723,7 +544,7 @@ func (e *Engine) RunPrepared(ctx context.Context, prepared *PreparedExecution) (
 	if prepared != nil {
 		internal = prepared.internal
 	}
-	result, err := e.runner.RunPrepared(ctx, internal)
+	result, err := e.internal.RunPrepared(ctx, internal)
 	if err != nil {
 		return nil, mapPublicError(err)
 	}
--- a/engine_test.go
+++ b/engine_test.go
@@ -2546,6 +2546,38 @@ func TestInMemoryProfileExtraParamsAreCopiedAcrossPublicBoundary(t *testing.T) {
 	}
 }

+func TestWithProfilesCopiesDefinitionsWhenApplied(t *testing.T) {
+	nested := map[string]any{"value": "when option is created"}
+	option := promptkit.WithProfiles(promptkit.Profile{
+		ID:          "profile",
+		Endpoint:    "http://copy.example/v1",
+		Model:       "copy-model",
+		ExtraParams: map[string]any{"nested": nested},
+	})
+	nested["value"] = "when option is applied"
+
+	engine, err := promptkit.NewEngine(promptkit.Config{PromptDir: frameworkPromptDir}, option)
+	if err != nil {
+		t.Fatalf("construct engine: %v", err)
+	}
+	nested["value"] = "after construction"
+
+	prepared, err := engine.Prepare(context.Background(), promptkit.RunRequest{
+		PromptID:  frameworkMarkdownSummaryPromptID,
+		ProfileID: "profile",
+		Inputs: map[string]promptkit.ArtifactRef{
+			"transcript": promptkit.Inline("Rin opens the gate."),
+			"glossary":   promptkit.Inline("gate: A guarded passage."),
+		},
+	})
+	if err != nil {
+		t.Fatalf("prepare with copied profile: %v", err)
+	}
+	if got := prepared.EffectiveModelParams.ExtraParams["nested"].(map[string]any)["value"]; got != "when option is applied" {
+		t.Fatalf("profile copy value = %q, want value at option application", got)
+	}
+}
+
 func TestWithProfilesRejectsInvalidExtraParams(t *testing.T) {
 	tests := []struct {
 		name        string
--- a/go.mod
+++ b/go.mod
@@ -3,8 +3,8 @@ module gitea.maximumdirect.net/eric/promptkit
 go 1.25.5

 require (
-	gitea.maximumdirect.net/eric/promptkit-backend-openrouter v1.0.0
-	gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome v1.0.0
+	gitea.maximumdirect.net/eric/promptkit-backend-openrouter/v2 v2.20260922.1
+	gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome/v2 v2.20260922.0
 	github.com/santhosh-tekuri/jsonschema/v6 v6.0.2
 	gopkg.in/yaml.v3 v3.0.1
 )
--- a/go.sum
+++ b/go.sum
@@ -1,7 +1,7 @@
-gitea.maximumdirect.net/eric/promptkit-backend-openrouter v1.0.0 h1:lc062euk2qseO//D762i3JaFyulDNML3eQQX7DkYTho=
-gitea.maximumdirect.net/eric/promptkit-backend-openrouter v1.0.0/go.mod h1:AIa7kAu2mfrRQgcspe4L+DW51WqgnALQT60lqkEywJI=
-gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome v1.0.0 h1:j9YY7wsTVjzke2kHH4YAzpU0oUpM+x+nXwl1IeS+2eg=
-gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome v1.0.0/go.mod h1:4RNS+LILDg4JbS4Ts9Lwy1C92wauXJIbeQaalps4Koo=
+gitea.maximumdirect.net/eric/promptkit-backend-openrouter/v2 v2.20260922.1 h1:S2/Q/JDE+m8Ca3pDhAjVbfYrdlEhs9blj0STgNopHo0=
+gitea.maximumdirect.net/eric/promptkit-backend-openrouter/v2 v2.20260922.1/go.mod h1:a3VBbh9oaGXD6ruxhtwHj+AWW6DY/SSyby1QtMmYSUo=
+gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome/v2 v2.20260922.0 h1:Y0EXc3eh12eKW2NrOviVqdk3oBo6UUjopt1YAa1B3Oc=
+gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome/v2 v2.20260922.0/go.mod h1:mtgD1E0SGm0e/I8Ffhz+AYX7GN7RKUWJXehNFIKHs4Y=
 github.com/dlclark/regexp2 v1.11.0 h1:G/nrcoOa7ZXlpoa/91N3X7mM3r8eIlMBBJZvsz/mxKI=
 github.com/dlclark/regexp2 v1.11.0/go.mod h1:DHkYz0B9wPfa6wondMfaivmHpzrQ3v9q8cnmRbL6yW8=
 github.com/santhosh-tekuri/jsonschema/v6 v6.0.2 h1:KRzFb2m7YtdldCEkzs6KqmJw4nqEVZGK7IN2kJkjTuQ=
--- a/internal/catalog/catalog.go
+++ b/internal/catalog/catalog.go
@@ -64,6 +64,9 @@ func Load(sources ...Source) (Set, error) {
 		}
 		resolvingRepository := profile.NewResolvingRepository(repository)
 		for _, entry := range metadata {
+			if strings.HasPrefix(entry.ID, "promptkit-") {
+				return Set{}, fmt.Errorf("catalog %s: %s uses the reserved promptkit- profile ID prefix", source.Name, entry.Path)
+			}
 			if profileIDs[entry.ID] {
 				return Set{}, fmt.Errorf("catalog %s: %s duplicates an earlier profile ID", source.Name, entry.Path)
 			}
--- a/internal/catalog/catalog_test.go
+++ b/internal/catalog/catalog_test.go
@@ -1,24 +1,19 @@
 package catalog

 import (
-	"bytes"
 	"context"
 	"encoding/json"
 	"fmt"
 	"io/fs"
-	"os"
-	"path/filepath"
-	"reflect"
-	"sort"
 	"strings"
 	"testing"
 	"testing/fstest"

-	openrouter "gitea.maximumdirect.net/eric/promptkit-backend-openrouter"
-	rakestrawhome "gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome"
+	openrouter "gitea.maximumdirect.net/eric/promptkit-backend-openrouter/v2"
+	rakestrawhome "gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome/v2"
 )

-func TestLoadPublishedCatalogsMatchCompatibilityFixture(t *testing.T) {
+func TestLoadPublishedCatalogs(t *testing.T) {
 	loaded, err := Load(
 		Source{Name: "OpenRouter", ExpectedBackendID: "openrouter", FS: openrouter.FS(), Root: openrouter.Root},
 		Source{Name: "Rakestrawhome", ExpectedBackendID: "rakestrawhome", FS: rakestrawhome.FS(), Root: rakestrawhome.Root},
@@ -26,22 +21,48 @@ func TestLoadPublishedCatalogsMatchCompatibilityFixture(t *testing.T) {
 	if err != nil {
 		t.Fatalf("load published catalogs: %v", err)
 	}
-	expected := loadCompatibilityFixture(t)
-	expectedIDs := fixtureProfileIDs(t, expected)
-	if !reflect.DeepEqual(loaded.profileIDs, expectedIDs) {
-		t.Fatalf("published profile IDs differ from compatibility fixture: got %q, want %q", loaded.profileIDs, expectedIDs)
+	if loaded.Profiles == nil || len(loaded.profileIDs) == 0 {
+		t.Fatalf("published catalogs have no usable profiles: %#v", loaded)
 	}
-	actual := catalogValue(t, loaded)
-	actualJSON, err := json.Marshal(actual)
-	if err != nil {
-		t.Fatalf("encode loaded catalogs: %v", err)
+	if _, err := loaded.Profiles.GetProfile(context.Background(), "gemini-flash-latest"); err != nil {
+		t.Fatalf("load maintained standard-profile base: %v", err)
 	}
-	expectedJSON, err := json.Marshal(expected)
-	if err != nil {
-		t.Fatalf("encode compatibility fixture: %v", err)
+
+	expectedBackends := map[string]struct {
+		endpoint         string
+		apiKeyEnv        string
+		concurrencyLimit int
+		queueCapacity    int
+	}{
+		"openrouter": {
+			endpoint:         "https://openrouter.ai/api/v1",
+			apiKeyEnv:        "OPENROUTER_API_KEY",
+			concurrencyLimit: 16,
+			queueCapacity:    1024,
+		},
+		"rakestrawhome": {
+			endpoint:         "https://inference.ai.rakestrawhome.com/v1",
+			apiKeyEnv:        "RAKESTRAWHOME_INFERENCE_API_KEY",
+			concurrencyLimit: 4,
+			queueCapacity:    1024,
+		},
 	}
-	if !bytes.Equal(actualJSON, expectedJSON) {
-		t.Fatalf("published catalogs differ from compatibility fixture: got %#v, want %#v", actual, expected)
+	if len(loaded.Backends) != len(expectedBackends) {
+		t.Fatalf("published backend count = %d, want %d", len(loaded.Backends), len(expectedBackends))
+	}
+	for _, definition := range loaded.Backends {
+		expected, found := expectedBackends[definition.ID]
+		if !found {
+			t.Fatalf("unexpected published backend %q", definition.ID)
+		}
+		if definition.Endpoint != expected.endpoint ||
+			definition.APIKeyEnv != expected.apiKeyEnv ||
+			definition.ConcurrencyLimit != expected.concurrencyLimit ||
+			definition.QueueCapacity != expected.queueCapacity ||
+			!definition.QueueCapacitySet ||
+			definition.ExtraParams != nil {
+			t.Fatalf("unexpected published backend definition: %#v", definition)
+		}
 	}
 }

@@ -193,6 +214,39 @@ func TestLoadRejectsInvalidCatalogProfiles(t *testing.T) {
 	}
 }

+func TestLoadReservesPromptkitProfilePrefixForCatalogs(t *testing.T) {
+	tests := map[string]struct {
+		profileID string
+		wantError bool
+	}{
+		"maintained name": {
+			profileID: "promptkit-openrouter-standard",
+			wantError: true,
+		},
+		"other reserved name": {
+			profileID: "promptkit-example",
+			wantError: true,
+		},
+		"ordinary name": {
+			profileID: "ordinary-profile",
+		},
+	}
+	for name, test := range tests {
+		t.Run(name, func(t *testing.T) {
+			fsys := validCatalogFS("one")
+			fsys["catalog/profiles/one-profile.yml"].Data = []byte(validProfile(test.profileID, "one"))
+
+			_, err := Load(testSource("one", fsys))
+			if (err != nil) != test.wantError {
+				t.Fatalf("Load() error = %v, want error %t", err, test.wantError)
+			}
+			if err != nil && !strings.Contains(err.Error(), "catalog one: one-profile.yml") {
+				t.Fatalf("Load() error = %v, want catalog source and path context", err)
+			}
+		})
+	}
+}
+
 func TestLoadRejectsCrossCatalogConflicts(t *testing.T) {
 	t.Run("duplicate backend", func(t *testing.T) {
 		second := catalogFS("one", map[string]string{
@@ -265,68 +319,6 @@ func TestLoadReturnsDefensiveCatalogValues(t *testing.T) {
 	}
 }

-func loadCompatibilityFixture(t *testing.T) map[string]any {
-	t.Helper()
-	data, err := os.ReadFile(filepath.Join("..", "..", "testdata", "builtin-catalog-v1.json"))
-	if err != nil {
-		t.Fatalf("read fixture: %v", err)
-	}
-	var value map[string]any
-	if err := json.Unmarshal(data, &value); err != nil {
-		t.Fatalf("decode fixture: %v", err)
-	}
-	return value
-}
-
-func fixtureProfileIDs(t *testing.T, fixture map[string]any) []string {
-	t.Helper()
-	profiles, ok := fixture["profiles"].([]any)
-	if !ok {
-		t.Fatal("compatibility fixture profiles are malformed")
-	}
-	ids := make([]string, 0, len(profiles))
-	for _, entry := range profiles {
-		profileValue, ok := entry.(map[string]any)
-		if !ok {
-			t.Fatal("compatibility fixture profile is malformed")
-		}
-		id, ok := profileValue["id"].(string)
-		if !ok {
-			t.Fatal("compatibility fixture profile ID is malformed")
-		}
-		ids = append(ids, id)
-	}
-	sort.Strings(ids)
-	return ids
-}
-
-func catalogValue(t *testing.T, loaded Set) map[string]any {
-	t.Helper()
-	backends := make([]any, 0, len(loaded.Backends))
-	for _, backend := range loaded.Backends {
-		backends = append(backends, map[string]any{"id": backend.ID, "endpoint": backend.Endpoint, "api_key_env": backend.APIKeyEnv, "extra_params": interfaceValue(backend.ExtraParams), "concurrency_limit": backend.ConcurrencyLimit, "queue_capacity": backend.QueueCapacity, "queue_capacity_set": backend.QueueCapacitySet})
-	}
-	sort.Slice(backends, func(left, right int) bool {
-		return backends[left].(map[string]any)["id"].(string) < backends[right].(map[string]any)["id"].(string)
-	})
-	actualProfiles := make([]any, 0, len(loaded.profileIDs))
-	for _, id := range loaded.profileIDs {
-		profile, err := loaded.Profiles.GetProfile(context.Background(), id)
-		if err != nil {
-			t.Fatalf("load profile %q: %v", id, err)
-		}
-		actualProfiles = append(actualProfiles, map[string]any{"id": profile.ID, "base_profile": profile.BaseProfileID, "backend": profile.BackendID, "endpoint": profile.Endpoint, "model": profile.Model, "temperature": profile.Temperature, "max_tokens": profile.MaxTokens, "top_p": profile.TopP, "timeout_seconds": profile.TimeoutSeconds, "service_tier": profile.ServiceTier, "reasoning_effort": profile.ReasoningEffort, "api_key_env": profile.APIKeyEnv, "api_key_required": profile.APIKeyRequired, "extra_params": interfaceValue(profile.ExtraParams)})
-	}
-	return map[string]any{"backends": backends, "profiles": actualProfiles}
-}
-
-func interfaceValue(value map[string]any) any {
-	if value == nil {
-		return nil
-	}
-	return value
-}
-
 func testSource(id string, fsys fs.FS) Source {
 	return Source{Name: id, ExpectedBackendID: id, FS: fsys, Root: "catalog"}
 }
--- a/internal/engine/engine.go
+++ b/internal/engine/engine.go
@@ -0,0 +1,277 @@
+// Package engine assembles Promptkit's internal execution components.
+package engine
+
+import (
+	"context"
+	"fmt"
+	"io/fs"
+	"net/http"
+	"os"
+	"path/filepath"
+	"strings"
+	"time"
+
+	openrouter "gitea.maximumdirect.net/eric/promptkit-backend-openrouter/v2"
+	rakestrawhome "gitea.maximumdirect.net/eric/promptkit-backend-rakestrawhome/v2"
+	"gitea.maximumdirect.net/eric/promptkit/internal/artifact"
+	"gitea.maximumdirect.net/eric/promptkit/internal/backend"
+	"gitea.maximumdirect.net/eric/promptkit/internal/capacity"
+	"gitea.maximumdirect.net/eric/promptkit/internal/catalog"
+	"gitea.maximumdirect.net/eric/promptkit/internal/defaults"
+	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
+	"gitea.maximumdirect.net/eric/promptkit/internal/llm"
+	"gitea.maximumdirect.net/eric/promptkit/internal/profile"
+	"gitea.maximumdirect.net/eric/promptkit/internal/prompt"
+	"gitea.maximumdirect.net/eric/promptkit/internal/promptdef"
+	"gitea.maximumdirect.net/eric/promptkit/internal/usecase"
+	"gitea.maximumdirect.net/eric/promptkit/internal/validate"
+)
+
+// Config carries construction settings selected by the public facade.
+type Config struct {
+	PromptDir  string
+	ProfileDir string
+	SchemaDir  string
+	Timeout    time.Duration
+	HTTPClient *http.Client
+}
+
+// Options collects construction choices from the public facade.
+type Options struct {
+	llmClient             llm.Client
+	artifactReader        artifact.Reader
+	promptDefinitions     promptdef.Repository
+	profiles              profile.Repository
+	fallbackProfiles      profile.Repository
+	memoryProfiles        profile.Repository
+	backends              []domain.Backend
+	validator             validate.Validator
+	promptSource          bool
+	profileSource         bool
+	fallbackProfileSource bool
+	memorySource          bool
+	validatorSource       bool
+	artifactSource        bool
+}
+
+// SetLLMClient selects the client collaborator for one engine.
+func (o *Options) SetLLMClient(client llm.Client) { o.llmClient = client }
+
+// SetArtifactReader selects the artifact collaborator for one engine.
+func (o *Options) SetArtifactReader(reader artifact.Reader) {
+	o.artifactReader = reader
+	o.artifactSource = true
+}
+
+// SetPromptFS selects a prompt source rooted in fsys.
+func (o *Options) SetPromptFS(fsys fs.FS, root string) error {
+	if err := validateSourceFS(fsys, root); err != nil {
+		return err
+	}
+	o.promptDefinitions = promptdef.NewFSRepository(fsys, root)
+	o.promptSource = true
+	return nil
+}
+
+// SetPromptFile selects a single prompt file.
+func (o *Options) SetPromptFile(path string) error {
+	fsys, root, directory, err := fileSource(path)
+	if err != nil {
+		return err
+	}
+	o.promptDefinitions = promptdef.NewFileRepository(fsys, root, directory)
+	o.promptSource = true
+	return nil
+}
+
+// SetProfileFS selects an ordinary profile source rooted in fsys.
+func (o *Options) SetProfileFS(fsys fs.FS, root string) error {
+	if err := validateSourceFS(fsys, root); err != nil {
+		return err
+	}
+	o.profiles = profile.NewFSRepository(fsys, root)
+	o.profileSource = true
+	return nil
+}
+
+// SetProfileFile selects a single ordinary profile file.
+func (o *Options) SetProfileFile(path string) error {
+	fsys, root, _, err := fileSource(path)
+	if err != nil {
+		return err
+	}
+	o.profiles = profile.NewFSRepository(fsys, root)
+	o.profileSource = true
+	return nil
+}
+
+// SetFallbackProfileFS selects a fallback profile source rooted in fsys.
+func (o *Options) SetFallbackProfileFS(fsys fs.FS, root string) error {
+	if err := validateSourceFS(fsys, root); err != nil {
+		return err
+	}
+	o.fallbackProfiles = profile.NewFSRepository(fsys, root)
+	o.fallbackProfileSource = true
+	return nil
+}
+
+// SetMemoryProfiles validates and stores application-owned profile definitions.
+func (o *Options) SetMemoryProfiles(definitions []domain.ExecutionProfile) error {
+	repository, err := profile.NewMemoryRepository(definitions)
+	if err != nil {
+		return err
+	}
+	o.memoryProfiles = repository
+	o.memorySource = true
+	return nil
+}
+
+// AddBackend appends one backend registration.
+func (o *Options) AddBackend(backend domain.Backend) { o.backends = append(o.backends, backend) }
+
+// SetSchemaFS selects a schema source rooted in fsys.
+func (o *Options) SetSchemaFS(fsys fs.FS, root string) error {
+	if err := validateSourceFS(fsys, root); err != nil {
+		return err
+	}
+	o.validator = validate.NewFSValidator(fsys, root)
+	o.validatorSource = true
+	return nil
+}
+
+// SetSchemaFile selects a single schema file.
+func (o *Options) SetSchemaFile(path string) error {
+	fsys, root, _, err := fileSource(path)
+	if err != nil {
+		return err
+	}
+	o.validator = validate.NewFSValidator(fsys, root)
+	o.validatorSource = true
+	return nil
+}
+
+// Engine forwards domain operations to the single assembled use-case runner.
+type Engine struct {
+	runner *usecase.Runner
+}
+
+// New assembles an engine from facade-selected configuration and collaborators.
+func New(cfg Config, options Options) (*Engine, error) {
+	promptDefinitions := options.promptDefinitions
+	if !options.promptSource {
+		if strings.TrimSpace(cfg.PromptDir) == "" {
+			return nil, fmt.Errorf("prompt directory is required")
+		}
+		promptDefinitions = promptdef.NewFilesystemRepository(cfg.PromptDir)
+	}
+
+	maintained, err := catalog.Load(
+		catalog.Source{Name: "OpenRouter", ExpectedBackendID: backend.OpenRouterID, FS: openrouter.FS(), Root: openrouter.Root},
+		catalog.Source{Name: "Rakestrawhome", ExpectedBackendID: backend.RakestrawHomeID, FS: rakestrawhome.FS(), Root: rakestrawhome.Root},
+	)
+	if err != nil {
+		return nil, fmt.Errorf("failed to load maintained catalogs: %w", err)
+	}
+
+	maintainedProfiles, err := newMaintainedProfileRepository(maintained.Profiles, maintained.Backends)
+	if err != nil {
+		return nil, fmt.Errorf("failed to construct Promptkit-maintained profiles: %w", err)
+	}
+
+	profiles := newProfileRepository(cfg.ProfileDir, options, maintainedProfiles)
+	registry, err := backend.NewRegistry(maintained.Backends, options.backends)
+	if err != nil {
+		return nil, fmt.Errorf("failed to construct backend registry: %w", err)
+	}
+	manager, err := capacity.NewManager(registry.CapacityPolicies())
+	if err != nil {
+		return nil, fmt.Errorf("failed to construct backend capacity manager: %w", err)
+	}
+
+	validator := options.validator
+	if !options.validatorSource {
+		schemaDir := cfg.SchemaDir
+		if strings.TrimSpace(schemaDir) == "" {
+			schemaDir = defaults.SchemaDirDefault
+		}
+		validator = validate.NewStandardValidator(schemaDir)
+	}
+	client := options.llmClient
+	if client == nil {
+		client, err = llm.NewOpenAICompatibleClient(llm.OpenAICompatibleConfig{Timeout: cfg.Timeout, HTTPClient: cfg.HTTPClient})
+		if err != nil {
+			return nil, err
+		}
+	}
+	client = capacity.NewClient(manager, client)
+	reader := options.artifactReader
+	if !options.artifactSource {
+		reader = artifact.NewCompositeReader()
+	}
+
+	return &Engine{runner: usecase.NewRunnerWithRepairer(promptDefinitions, profiles, registry, reader, prompt.NewGoRenderer(), client, validator, usecase.NewDefaultOutputRepairer(client), manager)}, nil
+}
+
+func newProfileRepository(profileDir string, options Options, maintained profile.Repository) profile.Repository {
+	repository := maintained
+	if options.fallbackProfileSource {
+		repository = profile.NewOverlayRepository(options.fallbackProfiles, repository)
+	}
+	if options.profileSource {
+		repository = profile.NewOverlayRepository(options.profiles, repository)
+	} else if strings.TrimSpace(profileDir) != "" {
+		repository = profile.NewOverlayRepository(profile.NewFilesystemRepository(profileDir), repository)
+	}
+	if options.memorySource {
+		repository = profile.NewOverlayRepository(options.memoryProfiles, repository)
+	}
+	return profile.NewResolvingRepository(repository)
+}
+
+func validateSourceFS(fsys fs.FS, root string) error {
+	if fsys == nil {
+		return fmt.Errorf("source filesystem is nil")
+	}
+	if strings.TrimSpace(root) == "" {
+		return fmt.Errorf("source root is required")
+	}
+	return nil
+}
+
+func fileSource(name string) (fs.FS, string, string, error) {
+	if strings.TrimSpace(name) == "" {
+		return nil, "", "", fmt.Errorf("source path is required")
+	}
+	directory := filepath.Dir(name)
+	base := filepath.Base(name)
+	if base == "." || base == string(filepath.Separator) {
+		return nil, "", "", fmt.Errorf("source path must name a file")
+	}
+	info, err := os.Stat(name)
+	if err != nil {
+		return nil, "", "", fmt.Errorf("failed to access source file %q: %w", name, err)
+	}
+	if info.IsDir() {
+		return nil, "", "", fmt.Errorf("source path %q must be a file", name)
+	}
+	return os.DirFS(directory), filepath.ToSlash(base), directory, nil
+}
+
+func (e *Engine) InspectPrompt(ctx context.Context, id, version string) (*domain.PromptInspection, error) {
+	return e.runner.InspectPrompt(ctx, id, version)
+}
+func (e *Engine) InspectProfile(ctx context.Context, id string) (*domain.ProfileInspection, error) {
+	return e.runner.InspectProfile(ctx, id)
+}
+func (e *Engine) Prepare(ctx context.Context, request domain.RunRequest) (*domain.PreparedRun, error) {
+	return e.runner.Prepare(ctx, request)
+}
+func (e *Engine) PrepareExecution(ctx context.Context, request domain.RunRequest) (*usecase.PreparedExecution, error) {
+	return e.runner.PrepareExecution(ctx, request)
+}
+func (e *Engine) Run(ctx context.Context, request domain.RunRequest) (*domain.RunResult, error) {
+	return e.runner.Run(ctx, request)
+}
+func (e *Engine) RunPrepared(ctx context.Context, prepared *usecase.PreparedExecution) (*domain.RunResult, error) {
+	return e.runner.RunPrepared(ctx, prepared)
+}
--- a/internal/engine/maintained_profiles.go
+++ b/internal/engine/maintained_profiles.go
@@ -0,0 +1,50 @@
+package engine
+
+import (
+	"context"
+	"fmt"
+
+	"gitea.maximumdirect.net/eric/promptkit/internal/backend"
+	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
+	"gitea.maximumdirect.net/eric/promptkit/internal/profile"
+)
+
+func maintainedProfileDefinitions() []domain.ExecutionProfile {
+	return []domain.ExecutionProfile{
+		{
+			ID:            "promptkit-openrouter-standard",
+			BaseProfileID: "gemini-flash-latest",
+		},
+		{
+			ID:        "promptkit-openrouter-auto",
+			BackendID: backend.OpenRouterID,
+			Model:     "openrouter/auto",
+		},
+	}
+}
+
+func newMaintainedProfileRepository(catalogProfiles profile.Repository, maintainedBackends []domain.Backend) (profile.Repository, error) {
+	definitions := maintainedProfileDefinitions()
+	owned, err := profile.NewMemoryRepository(definitions)
+	if err != nil {
+		return nil, fmt.Errorf("create Promptkit-maintained profiles: %w", err)
+	}
+
+	combined := profile.NewOverlayRepository(owned, catalogProfiles)
+	resolved := profile.NewResolvingRepository(combined)
+	registry, err := backend.NewRegistry(maintainedBackends, nil)
+	if err != nil {
+		return nil, fmt.Errorf("construct maintained backend registry: %w", err)
+	}
+	for _, definition := range definitions {
+		effective, err := resolved.GetProfile(context.Background(), definition.ID)
+		if err != nil {
+			return nil, fmt.Errorf("resolve Promptkit-maintained profile %q: %w", definition.ID, err)
+		}
+		if _, err := registry.GetBackend(effective.BackendID); err != nil {
+			return nil, fmt.Errorf("Promptkit-maintained profile %q selects unavailable backend %q: %w", definition.ID, effective.BackendID, err)
+		}
+	}
+
+	return combined, nil
+}
--- a/internal/engine/maintained_profiles_test.go
+++ b/internal/engine/maintained_profiles_test.go
@@ -0,0 +1,78 @@
+package engine
+
+import (
+	"context"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/promptkit/internal/backend"
+	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
+	"gitea.maximumdirect.net/eric/promptkit/internal/profile"
+)
+
+func TestNewMaintainedProfileRepository(t *testing.T) {
+	newCatalogProfiles := func(t *testing.T, definitions []domain.ExecutionProfile) profile.Repository {
+		t.Helper()
+		repository, err := profile.NewMemoryRepository(definitions)
+		if err != nil {
+			t.Fatalf("create catalog profiles: %v", err)
+		}
+		return repository
+	}
+	newBackend := func(id string) domain.Backend {
+		return domain.Backend{ID: id, Endpoint: "https://" + id + ".example/v1", APIKeyEnv: "TEST_API_KEY"}
+	}
+
+	t.Run("resolves inherited and direct definitions", func(t *testing.T) {
+		repository, err := newMaintainedProfileRepository(
+			newCatalogProfiles(t, []domain.ExecutionProfile{{
+				ID:        "gemini-flash-latest",
+				BackendID: backend.OpenRouterID,
+				Model:     "catalog-selected-model",
+			}}),
+			[]domain.Backend{newBackend(backend.OpenRouterID)},
+		)
+		if err != nil {
+			t.Fatalf("create maintained profiles: %v", err)
+		}
+
+		resolved := profile.NewResolvingRepository(repository)
+		standard, err := resolved.GetProfile(context.Background(), "promptkit-openrouter-standard")
+		if err != nil {
+			t.Fatalf("resolve inherited profile: %v", err)
+		}
+		if standard.BackendID != backend.OpenRouterID || standard.Model != "catalog-selected-model" {
+			t.Fatalf("unexpected inherited profile: %#v", standard)
+		}
+
+		auto, err := resolved.GetProfile(context.Background(), "promptkit-openrouter-auto")
+		if err != nil {
+			t.Fatalf("resolve direct profile: %v", err)
+		}
+		definitions := maintainedProfileDefinitions()
+		if auto.BackendID != definitions[1].BackendID || auto.Model != definitions[1].Model {
+			t.Fatalf("unexpected direct profile: %#v", auto)
+		}
+	})
+
+	t.Run("rejects a missing inherited base", func(t *testing.T) {
+		if _, err := newMaintainedProfileRepository(
+			newCatalogProfiles(t, nil),
+			[]domain.Backend{newBackend(backend.OpenRouterID)},
+		); err == nil {
+			t.Fatal("expected missing base error")
+		}
+	})
+
+	t.Run("rejects an unavailable effective backend", func(t *testing.T) {
+		if _, err := newMaintainedProfileRepository(
+			newCatalogProfiles(t, []domain.ExecutionProfile{{
+				ID:        "gemini-flash-latest",
+				BackendID: "other",
+				Model:     "catalog-selected-model",
+			}}),
+			[]domain.Backend{newBackend("other")},
+		); err == nil {
+			t.Fatal("expected unavailable backend error")
+		}
+	})
+}
--- a/internal/profile/memory_repository.go
+++ b/internal/profile/memory_repository.go
@@ -0,0 +1,50 @@
+package profile
+
+import (
+	"context"
+	"fmt"
+
+	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
+	"gitea.maximumdirect.net/eric/promptkit/internal/jsonvalue"
+)
+
+// NewMemoryRepository constructs an immutable repository from profile
+// definitions supplied by an internal caller.
+func NewMemoryRepository(definitions []domain.ExecutionProfile) (Repository, error) {
+	repository := &memoryRepository{profiles: make(map[string]domain.ExecutionProfile, len(definitions))}
+	for _, definition := range definitions {
+		extraParams, err := jsonvalue.CopyMap(definition.ExtraParams)
+		if err != nil {
+			return nil, err
+		}
+		definition.ExtraParams = extraParams
+		if err := NormalizeAndValidateDefinition(&definition); err != nil {
+			return nil, err
+		}
+		if _, exists := repository.profiles[definition.ID]; exists {
+			return nil, fmt.Errorf("duplicate profile id %q", definition.ID)
+		}
+		repository.profiles[definition.ID] = definition
+	}
+	return repository, nil
+}
+
+type memoryRepository struct {
+	profiles map[string]domain.ExecutionProfile
+}
+
+func (r *memoryRepository) GetProfile(_ context.Context, id string) (*domain.ExecutionProfile, error) {
+	if r == nil {
+		return nil, ErrProfileNotFound
+	}
+	definition, found := r.profiles[id]
+	if !found {
+		return nil, ErrProfileNotFound
+	}
+	extraParams, err := jsonvalue.CopyMap(definition.ExtraParams)
+	if err != nil {
+		return nil, fmt.Errorf("copy memory profile %q: %w", definition.ID, err)
+	}
+	definition.ExtraParams = extraParams
+	return &definition, nil
+}
--- a/internal/profile/memory_repository_test.go
+++ b/internal/profile/memory_repository_test.go
@@ -0,0 +1,91 @@
+package profile
+
+import (
+	"context"
+	"errors"
+	"testing"
+
+	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
+)
+
+func TestMemoryRepositoryOwnsNormalizedDefinitions(t *testing.T) {
+	nested := map[string]any{"value": "original"}
+	definitions := []domain.ExecutionProfile{{
+		ID:          " profile ",
+		BackendID:   " backend ",
+		Endpoint:    " https://example.test/v1/ ",
+		Model:       "model",
+		ExtraParams: map[string]any{"nested": nested},
+	}}
+
+	repository, err := NewMemoryRepository(definitions)
+	if err != nil {
+		t.Fatalf("construct repository: %v", err)
+	}
+	nested["value"] = "mutated input"
+
+	first, err := repository.GetProfile(context.Background(), "profile")
+	if err != nil {
+		t.Fatalf("load profile: %v", err)
+	}
+	if first.ID != "profile" || first.BackendID != "backend" || first.Endpoint != "https://example.test/v1/" {
+		t.Fatalf("normalized definition = %#v", first)
+	}
+	if first.ExtraParams["nested"].(map[string]any)["value"] != "original" {
+		t.Fatalf("repository retained input mutation: %#v", first.ExtraParams)
+	}
+	first.ExtraParams["nested"].(map[string]any)["value"] = "mutated result"
+
+	second, err := repository.GetProfile(context.Background(), "profile")
+	if err != nil {
+		t.Fatalf("reload profile: %v", err)
+	}
+	if second.ExtraParams["nested"].(map[string]any)["value"] != "original" {
+		t.Fatalf("repository retained result mutation: %#v", second.ExtraParams)
+	}
+}
+
+func TestMemoryRepositoryPreservesInheritanceAndRejectsInvalidDefinitions(t *testing.T) {
+	derived, err := NewMemoryRepository([]domain.ExecutionProfile{{
+		ID:              "derived",
+		BaseProfileID:   "base",
+		ReasoningEffort: "high",
+	}})
+	if err != nil {
+		t.Fatalf("construct derived repository: %v", err)
+	}
+	profile, err := derived.GetProfile(context.Background(), "derived")
+	if err != nil {
+		t.Fatalf("load derived profile: %v", err)
+	}
+	if profile.BaseProfileID != "base" || profile.ReasoningEffort != "high" {
+		t.Fatalf("derived profile = %#v", profile)
+	}
+	if _, err := derived.GetProfile(context.Background(), "missing"); !errors.Is(err, ErrProfileNotFound) {
+		t.Fatalf("missing profile error = %v, want ErrProfileNotFound", err)
+	}
+
+	tests := []struct {
+		name        string
+		definitions []domain.ExecutionProfile
+	}{
+		{
+			name: "normalized duplicate IDs",
+			definitions: []domain.ExecutionProfile{
+				{ID: " duplicate ", Endpoint: "https://one.example/v1", Model: "one"},
+				{ID: "duplicate", Endpoint: "https://two.example/v1", Model: "two"},
+			},
+		},
+		{
+			name:        "invalid extra parameters",
+			definitions: []domain.ExecutionProfile{{ID: "invalid", Endpoint: "https://example.test/v1", Model: "model", ExtraParams: map[string]any{"invalid": func() {}}}},
+		},
+	}
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			if _, err := NewMemoryRepository(test.definitions); err == nil {
+				t.Fatal("expected repository construction error")
+			}
+		})
+	}
+}
--- a/profile_inheritance_contract_test.go
+++ b/profile_inheritance_contract_test.go
@@ -18,7 +18,7 @@ func TestProfileInheritanceBuiltInAliasWorkflow(t *testing.T) {
 		SchemaDir: frameworkSchemaDir,
 	}, promptkit.WithProfiles(promptkit.Profile{
 		ID:              "weather-light",
-		BaseProfileID:   "deepseek-4-flash",
+		BaseProfileID:   "promptkit-openrouter-standard",
 		ReasoningEffort: "high",
 		TimeoutSeconds:  120,
 	}))
@@ -26,7 +26,7 @@ func TestProfileInheritanceBuiltInAliasWorkflow(t *testing.T) {
 		t.Fatalf("construct alias engine: %v", err)
 	}

-	base, err := engine.InspectProfile(context.Background(), "deepseek-4-flash")
+	base, err := engine.InspectProfile(context.Background(), "promptkit-openrouter-standard")
 	if err != nil {
 		t.Fatalf("inspect base: %v", err)
 	}
@@ -84,7 +84,7 @@ func TestProfileInheritanceYAMLAliasOfBuiltIn(t *testing.T) {
 	engine, err := promptkit.NewEngine(promptkit.Config{},
 		promptkit.WithPromptFS(fstest.MapFS{}, "."),
 		promptkit.WithProfileFS(fstest.MapFS{
-			"alias.yaml": &fstest.MapFile{Data: []byte("id: yaml-alias\nbase_profile: deepseek-4-flash\n")},
+			"alias.yaml": &fstest.MapFile{Data: []byte("id: yaml-alias\nbase_profile: promptkit-openrouter-standard\n")},
 		}, "."),
 	)
 	if err != nil {
--- a/profiles.go
+++ b/profiles.go
@@ -1,12 +1,7 @@
 package promptkit

 import (
-	"context"
-	"fmt"
-
 	"gitea.maximumdirect.net/eric/promptkit/internal/domain"
-	"gitea.maximumdirect.net/eric/promptkit/internal/jsonvalue"
-	"gitea.maximumdirect.net/eric/promptkit/internal/profile"
 )

 // OpenAICompatibleProfile returns an in-memory Profile for an OpenAI-compatible
@@ -50,43 +45,8 @@ func copyShallowAnyMap(src map[string]any) map[string]any {
 	return out
 }

-type memoryProfileRepository struct {
-	profiles map[string]domain.ExecutionProfile
-}
-
-func newMemoryProfileRepository(profiles []Profile) (*memoryProfileRepository, error) {
-	repo := &memoryProfileRepository{profiles: make(map[string]domain.ExecutionProfile, len(profiles))}
-	for _, publicProfile := range profiles {
-		prof, err := toDomainProfile(publicProfile)
-		if err != nil {
-			return nil, err
-		}
-		if _, exists := repo.profiles[prof.ID]; exists {
-			return nil, fmt.Errorf("duplicate profile id %q", prof.ID)
-		}
-		repo.profiles[prof.ID] = prof
-	}
-	return repo, nil
-}
-
-func (r *memoryProfileRepository) GetProfile(_ context.Context, id string) (*domain.ExecutionProfile, error) {
-	if r == nil {
-		return nil, profile.ErrProfileNotFound
-	}
-	prof, ok := r.profiles[id]
-	if !ok {
-		return nil, profile.ErrProfileNotFound
-	}
-	prof.ExtraParams = copyAnyMap(prof.ExtraParams)
-	return &prof, nil
-}
-
-func toDomainProfile(publicProfile Profile) (domain.ExecutionProfile, error) {
-	extraParams, err := jsonvalue.CopyMap(publicProfile.ExtraParams)
-	if err != nil {
-		return domain.ExecutionProfile{}, err
-	}
-	prof := domain.ExecutionProfile{
+func toDomainProfile(publicProfile Profile) domain.ExecutionProfile {
+	return domain.ExecutionProfile{
 		ID:              publicProfile.ID,
 		BaseProfileID:   publicProfile.BaseProfileID,
 		BackendID:       publicProfile.BackendID,
@@ -99,10 +59,6 @@ func toDomainProfile(publicProfile Profile) (domain.ExecutionProfile, error) {
 		ServiceTier:     publicProfile.ServiceTier,
 		ReasoningEffort: publicProfile.ReasoningEffort,
 		APIKeyRequired:  publicProfile.APIKeyRequired,
-		ExtraParams:     extraParams,
+		ExtraParams:     publicProfile.ExtraParams,
 	}
-	if err := profile.NormalizeAndValidateDefinition(&prof); err != nil {
-		return domain.ExecutionProfile{}, err
-	}
-	return prof, nil
 }
--- a/public_boundary_test.go
+++ b/public_boundary_test.go
@@ -0,0 +1,397 @@
+package promptkit_test
+
+import (
+	"encoding/json"
+	"fmt"
+	"go/ast"
+	"go/importer"
+	"go/parser"
+	"go/token"
+	"go/types"
+	"io"
+	"os"
+	"os/exec"
+	"runtime"
+	"sort"
+	"strings"
+	"testing"
+)
+
+func TestPublicFacadeDoesNotExposeInternalTypes(t *testing.T) {
+	metadata := listedPackages(t, "-export", ".")
+	if len(metadata) != 1 {
+		t.Fatalf("root package metadata count = %d, want one", len(metadata))
+	}
+
+	pkg := importCompiledPackage(t, metadata[0])
+	violations := publicSurfaceViolations(pkg, metadata[0].ImportPath)
+	if len(violations) > 0 {
+		t.Fatalf("public facade exposes internal implementation:\n%s", strings.Join(violations, "\n"))
+	}
+}
+
+func TestInternalProductionPackagesDoNotImportFacade(t *testing.T) {
+	root := listedPackages(t, ".")
+	if len(root) != 1 {
+		t.Fatalf("root package metadata count = %d, want one", len(root))
+	}
+
+	var violations []string
+	for _, pkg := range listedPackages(t, "./internal/...") {
+		for _, imported := range pkg.Imports {
+			if imported == root[0].ImportPath {
+				violations = append(violations, pkg.ImportPath)
+			}
+		}
+	}
+	sort.Strings(violations)
+	if len(violations) > 0 {
+		t.Fatalf("internal production packages import the public facade:\n%s", strings.Join(violations, "\n"))
+	}
+}
+
+func TestPublicBoundaryCheckerFixtures(t *testing.T) {
+	tests := []struct {
+		name       string
+		source     string
+		wantReject bool
+	}{
+		{
+			name: "private internal state and sealed option are allowed",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type privateState struct { value hidden.Value }
+type Public struct { state privateState }
+type Option interface { apply(*privateState) }
+`,
+		},
+		{
+			name: "returned private type method is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type result struct{}
+func (result) Leak() hidden.Value { return hidden.Value{} }
+func New() result { return result{} }
+`,
+			wantReject: true,
+		},
+		{
+			name: "reachable private pointer method is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type result struct{}
+func (*result) Leak() hidden.Value { return hidden.Value{} }
+type Public struct { Result result }
+`,
+			wantReject: true,
+		},
+		{
+			name: "internal generic argument is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type Box[T any] struct{}
+func New() Box[hidden.Value] { return Box[hidden.Value]{} }
+`,
+			wantReject: true,
+		},
+		{
+			name: "internal alias argument is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type Box[T any] = struct{}
+func New() Box[hidden.Value] { return Box[hidden.Value]{} }
+`,
+			wantReject: true,
+		},
+		{
+			name: "public generic argument and recursive methods are allowed",
+			source: `package facade
+type Value struct{}
+type Box[T any] struct{}
+func New() Box[Value] { return Box[Value]{} }
+type result struct{}
+func NewResult() result { return result{} }
+func (*result) Next() *result { return nil }
+`,
+		},
+		{
+			name: "direct internal signature is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+func Direct(value hidden.Value) {}
+`,
+			wantReject: true,
+		},
+		{
+			name: "nested internal signature is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+func Nested(values []map[string]hidden.Value) {}
+`,
+			wantReject: true,
+		},
+		{
+			name: "internal public field is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type Public struct { Value hidden.Value }
+`,
+			wantReject: true,
+		},
+		{
+			name: "internal alias is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type Public = hidden.Value
+`,
+			wantReject: true,
+		},
+		{
+			name: "promoted internal method is rejected",
+			source: `package facade
+import "example.test/facade/internal/hidden"
+type wrapper struct { hidden.Value }
+type Public struct { wrapper }
+`,
+			wantReject: true,
+		},
+	}
+
+	for _, test := range tests {
+		t.Run(test.name, func(t *testing.T) {
+			pkg := fixturePackage(t, test.source)
+			violations := publicSurfaceViolations(pkg, "example.test/facade")
+			if got := len(violations) > 0; got != test.wantReject {
+				t.Fatalf("rejected = %t, want %t; violations = %v", got, test.wantReject, violations)
+			}
+		})
+	}
+}
+
+type packageMetadata struct {
+	ImportPath string
+	Export     string
+	Imports    []string
+}
+
+func listedPackages(t *testing.T, args ...string) []packageMetadata {
+	t.Helper()
+	command := exec.Command("go", append([]string{"list", "-json"}, args...)...)
+	output, err := command.Output()
+	if err != nil {
+		t.Fatalf("go list %s: %v", strings.Join(args, " "), err)
+	}
+
+	decoder := json.NewDecoder(strings.NewReader(string(output)))
+	var packages []packageMetadata
+	for decoder.More() {
+		var metadata packageMetadata
+		if err := decoder.Decode(&metadata); err != nil {
+			t.Fatalf("decode go list %s: %v", strings.Join(args, " "), err)
+		}
+		packages = append(packages, metadata)
+	}
+	return packages
+}
+
+func importCompiledPackage(t *testing.T, root packageMetadata) *types.Package {
+	t.Helper()
+	exports := map[string]string{root.ImportPath: root.Export}
+	lookup := func(importPath string) (io.ReadCloser, error) {
+		export, ok := exports[importPath]
+		if !ok {
+			metadata := listedPackages(t, "-export", importPath)
+			if len(metadata) != 1 || metadata[0].Export == "" {
+				return nil, fmt.Errorf("export data unavailable for %s", importPath)
+			}
+			export = metadata[0].Export
+			exports[importPath] = export
+		}
+		return os.Open(export)
+	}
+
+	compiled := importer.ForCompiler(token.NewFileSet(), runtime.Compiler, lookup)
+	pkg, err := compiled.Import(root.ImportPath)
+	if err != nil {
+		t.Fatalf("import compiled root package: %v", err)
+	}
+	return pkg
+}
+
+func publicSurfaceViolations(pkg *types.Package, modulePath string) []string {
+	var violations []string
+	seen := map[types.Type]bool{}
+	record := func(where string, typ types.Type) {
+		violations = append(violations, fmt.Sprintf("%s: %s", where, typ.String()))
+	}
+	var inspect func(types.Type, string)
+	var inspectTuple func(*types.Tuple, string)
+	var inspectTypeParams func(*types.TypeParamList, string)
+	var inspectTypeArgs func(*types.TypeList, string)
+	var inspectMethods func(*types.Named, string)
+	inspect = func(typ types.Type, where string) {
+		if typ == nil || seen[typ] {
+			return
+		}
+		seen[typ] = true
+
+		switch value := typ.(type) {
+		case *types.Named:
+			inspectTypeArgs(value.TypeArgs(), where)
+			if isInternalPackage(value.Obj().Pkg(), modulePath) {
+				record(where, value)
+				return
+			}
+			if value.Obj().Pkg() == pkg {
+				inspectTypeParams(value.TypeParams(), where)
+				inspect(value.Underlying(), where)
+				inspectMethods(value, where)
+			}
+		case *types.Alias:
+			inspectTypeArgs(value.TypeArgs(), where)
+			if isInternalPackage(value.Obj().Pkg(), modulePath) {
+				record(where, value)
+				return
+			}
+			inspectTypeParams(value.TypeParams(), where)
+			inspect(types.Unalias(value), where)
+		case *types.Pointer:
+			inspect(value.Elem(), where)
+		case *types.Array:
+			inspect(value.Elem(), where)
+		case *types.Slice:
+			inspect(value.Elem(), where)
+		case *types.Map:
+			inspect(value.Key(), where)
+			inspect(value.Elem(), where)
+		case *types.Chan:
+			inspect(value.Elem(), where)
+		case *types.Struct:
+			for index := 0; index < value.NumFields(); index++ {
+				field := value.Field(index)
+				if field.Exported() {
+					inspect(field.Type(), where+"."+field.Name())
+				}
+			}
+		case *types.Interface:
+			value.Complete()
+			for index := 0; index < value.NumEmbeddeds(); index++ {
+				inspect(value.EmbeddedType(index), where)
+			}
+			for index := 0; index < value.NumMethods(); index++ {
+				method := value.Method(index)
+				if method.Exported() {
+					inspect(method.Type(), where+"."+method.Name())
+				}
+			}
+		case *types.Signature:
+			if value.Recv() != nil {
+				inspect(value.Recv().Type(), where)
+			}
+			inspectTuple(value.Params(), where)
+			inspectTuple(value.Results(), where)
+			inspectTypeParams(value.TypeParams(), where)
+		case *types.TypeParam:
+			inspect(value.Constraint(), where)
+		case *types.Union:
+			for index := 0; index < value.Len(); index++ {
+				inspect(value.Term(index).Type(), where)
+			}
+		}
+	}
+	inspectTuple = func(tuple *types.Tuple, where string) {
+		for index := 0; index < tuple.Len(); index++ {
+			inspect(tuple.At(index).Type(), where)
+		}
+	}
+	inspectTypeParams = func(params *types.TypeParamList, where string) {
+		if params == nil {
+			return
+		}
+		for index := 0; index < params.Len(); index++ {
+			inspect(params.At(index), where)
+		}
+	}
+	inspectTypeArgs = func(args *types.TypeList, where string) {
+		for index := 0; index < args.Len(); index++ {
+			inspect(args.At(index), where)
+		}
+	}
+	inspectMethods = func(named *types.Named, where string) {
+		for _, methodSet := range []*types.MethodSet{types.NewMethodSet(named), types.NewMethodSet(types.NewPointer(named))} {
+			for index := 0; index < methodSet.Len(); index++ {
+				selection := methodSet.At(index)
+				method := selection.Obj().(*types.Func)
+				if !method.Exported() {
+					continue
+				}
+				if isInternalPackage(method.Pkg(), modulePath) {
+					record(where+"."+method.Name(), selection.Type())
+					continue
+				}
+				inspect(selection.Type(), where+"."+method.Name())
+			}
+		}
+	}
+
+	for _, name := range pkg.Scope().Names() {
+		if token.IsExported(name) {
+			inspect(pkg.Scope().Lookup(name).Type(), name)
+		}
+	}
+	sort.Strings(violations)
+	return compactStrings(violations)
+}
+
+func isInternalPackage(pkg *types.Package, modulePath string) bool {
+	return pkg != nil && strings.HasPrefix(pkg.Path(), modulePath+"/internal/")
+}
+
+func compactStrings(values []string) []string {
+	if len(values) == 0 {
+		return nil
+	}
+	unique := values[:1]
+	for _, value := range values[1:] {
+		if value != unique[len(unique)-1] {
+			unique = append(unique, value)
+		}
+	}
+	return unique
+}
+
+func fixturePackage(t *testing.T, source string) *types.Package {
+	t.Helper()
+	const rootPath = "example.test/facade"
+	const internalPath = rootPath + "/internal/hidden"
+	fset := token.NewFileSet()
+	internalFile, err := parser.ParseFile(fset, "hidden.go", `package hidden
+type Value struct{}
+func (Value) Exposed() {}
+`, 0)
+	if err != nil {
+		t.Fatalf("parse internal fixture: %v", err)
+	}
+	internalPkg, err := (&types.Config{}).Check(internalPath, fset, []*ast.File{internalFile}, nil)
+	if err != nil {
+		t.Fatalf("type-check internal fixture: %v", err)
+	}
+	rootFile, err := parser.ParseFile(fset, "facade.go", source, 0)
+	if err != nil {
+		t.Fatalf("parse facade fixture: %v", err)
+	}
+	pkg, err := (&types.Config{Importer: fixtureImporter(func(path string) (*types.Package, error) {
+		if path == internalPath {
+			return internalPkg, nil
+		}
+		return nil, fmt.Errorf("unexpected fixture import %s", path)
+	})}).Check(rootPath, fset, []*ast.File{rootFile}, nil)
+	if err != nil {
+		t.Fatalf("type-check facade fixture: %v", err)
+	}
+	return pkg
+}
+
+type fixtureImporter func(string) (*types.Package, error)
+
+func (f fixtureImporter) Import(path string) (*types.Package, error) { return f(path) }
--- a/public_contract_test.go
+++ b/public_contract_test.go
@@ -1203,6 +1203,105 @@ func TestFallbackProfileSourcePrecedence(t *testing.T) {
 	})
 }

+func TestPromptkitOwnedProfilesUseExistingProfileWorkflows(t *testing.T) {
+	const (
+		standardID = "promptkit-openrouter-standard"
+		autoID     = "promptkit-openrouter-auto"
+	)
+
+	t.Run("inspection and preparation resolve both names", func(t *testing.T) {
+		engine, err := promptkit.NewEngine(promptkit.Config{},
+			promptkit.WithPromptFS(contractPromptFS("prompt", standardID, "message"), "."),
+		)
+		if err != nil {
+			t.Fatalf("construct engine: %v", err)
+		}
+
+		for _, profileID := range []string{standardID, autoID} {
+			inspection, err := engine.InspectProfile(context.Background(), profileID)
+			if err != nil {
+				t.Fatalf("inspect %q: %v", profileID, err)
+			}
+			prepared, err := engine.Prepare(context.Background(), promptkit.RunRequest{
+				PromptID:  "prompt",
+				ProfileID: profileID,
+				APIKey:    "test-key",
+			})
+			if err != nil {
+				t.Fatalf("prepare %q: %v", profileID, err)
+			}
+			if inspection.ProfileID != profileID ||
+				inspection.EffectiveModelParams.BackendID != promptkit.BackendOpenRouter ||
+				prepared.SelectedProfileID != profileID ||
+				prepared.SelectedBackendID != promptkit.BackendOpenRouter ||
+				!reflect.DeepEqual(prepared.EffectiveModelParams, inspection.EffectiveModelParams) {
+				t.Fatalf("inspection and preparation differ for %q: inspection=%#v prepared=%#v", profileID, inspection, prepared)
+			}
+		}
+	})
+
+	t.Run("consumer definitions override an owned profile and its base", func(t *testing.T) {
+		auto, err := promptkit.NewEngine(promptkit.Config{},
+			promptkit.WithPromptFS(contractPromptFS("auto", autoID, "message"), "."),
+			promptkit.WithProfiles(promptkit.Profile{
+				ID:       autoID,
+				Endpoint: "http://consumer.example/v1",
+				Model:    "consumer-auto-model",
+			}),
+		)
+		if err != nil {
+			t.Fatalf("construct override engine: %v", err)
+		}
+		autoPrepared, err := auto.Prepare(context.Background(), promptkit.RunRequest{PromptID: "auto"})
+		if err != nil {
+			t.Fatalf("prepare overridden profile: %v", err)
+		}
+		if autoPrepared.EffectiveModelParams.Model != "consumer-auto-model" {
+			t.Fatalf("owned profile override model = %q", autoPrepared.EffectiveModelParams.Model)
+		}
+
+		standard, err := promptkit.NewEngine(promptkit.Config{},
+			promptkit.WithPromptFS(contractPromptFS("standard", standardID, "message"), "."),
+			promptkit.WithProfiles(promptkit.Profile{
+				ID:       "gemini-flash-latest",
+				Endpoint: "http://consumer.example/v1",
+				Model:    "consumer-base-model",
+			}),
+		)
+		if err != nil {
+			t.Fatalf("construct inherited override engine: %v", err)
+		}
+		standardPrepared, err := standard.Prepare(context.Background(), promptkit.RunRequest{PromptID: "standard"})
+		if err != nil {
+			t.Fatalf("prepare profile with overridden base: %v", err)
+		}
+		if standardPrepared.EffectiveModelParams.Model != "consumer-base-model" {
+			t.Fatalf("owned profile base override model = %q", standardPrepared.EffectiveModelParams.Model)
+		}
+	})
+
+	t.Run("prompt default selection remains explicit", func(t *testing.T) {
+		engine, err := promptkit.NewEngine(promptkit.Config{},
+			promptkit.WithPromptFS(contractPromptFS("default", "application-default", "message"), "."),
+			promptkit.WithProfiles(promptkit.Profile{
+				ID:       "application-default",
+				Endpoint: "http://consumer.example/v1",
+				Model:    "consumer-default-model",
+			}),
+		)
+		if err != nil {
+			t.Fatalf("construct default engine: %v", err)
+		}
+		prepared, err := engine.Prepare(context.Background(), promptkit.RunRequest{PromptID: "default"})
+		if err != nil {
+			t.Fatalf("prepare default profile: %v", err)
+		}
+		if prepared.SelectedProfileID != "application-default" {
+			t.Fatalf("selected default profile = %q", prepared.SelectedProfileID)
+		}
+	})
+}
+
 func TestFallbackProfileSourcePreservesLazyLoadingAndErrors(t *testing.T) {
 	const profileID = "application-profile"

--- a/testdata/builtin-catalog-v1.json
+++ b/testdata/builtin-catalog-v1.json
@@ -1,424 +0,0 @@
-{
-    "backends": [
-        {
-            "id": "openrouter",
-            "endpoint": "https://openrouter.ai/api/v1",
-            "api_key_env": "OPENROUTER_API_KEY",
-            "extra_params": null,
-            "concurrency_limit": 16,
-            "queue_capacity": 1024,
-            "queue_capacity_set": true
-        },
-        {
-            "id": "rakestrawhome",
-            "endpoint": "https://inference.ai.rakestrawhome.com/v1",
-            "api_key_env": "RAKESTRAWHOME_INFERENCE_API_KEY",
-            "extra_params": null,
-            "concurrency_limit": 4,
-            "queue_capacity": 1024,
-            "queue_capacity_set": true
-        }
-    ],
-    "profiles": [
-        {
-            "id": "aion-2",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "aion-labs/aion-2.0",
-            "temperature": 0.72,
-            "max_tokens": 0,
-            "top_p": 0.95,
-            "timeout_seconds": 180,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "claude-fable-latest",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "~anthropic/claude-fable-latest",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 600,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "claude-haiku-latest",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "~anthropic/claude-haiku-latest",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "medium",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "claude-opus-latest",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "~anthropic/claude-opus-latest",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "claude-sonnet-latest",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "~anthropic/claude-sonnet-latest",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "deepseek-3-2",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "deepseek/deepseek-v3.2",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 180,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "deepseek-4-flash",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "deepseek/deepseek-v4-flash",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 180,
-            "service_tier": "flex",
-            "reasoning_effort": "",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "deepseek-4-pro",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "deepseek/deepseek-v4-pro",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 180,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gemini-2-flash",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "google/gemini-2.5-flash",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gemini-2-flash-lite",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "google/gemini-2.5-flash-lite",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gemini-2-pro",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "google/gemini-2.5-pro",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gemini-3-flash-lite",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "google/gemini-3.1-flash-lite",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gemini-flash-latest",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "~google/gemini-flash-latest",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gemini-pro-latest",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "~google/gemini-pro-latest",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gemma-4-31b",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "google/gemma-4-31b-it:exacto",
-            "temperature": 0.15,
-            "max_tokens": 0,
-            "top_p": 0.98,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gpt-5-mini",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "openai/gpt-5.4-mini",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "gpt-5-nano",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "openai/gpt-5.4-nano",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 240,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "minimax-m2",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "minimax/minimax-m2.5",
-            "temperature": 0.5,
-            "max_tokens": 0,
-            "top_p": 0.95,
-            "timeout_seconds": 180,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "minimax-m3",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "minimax/minimax-m3",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 180,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "mistral-large-2512",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "mistralai/mistral-large-2512",
-            "temperature": 0.15,
-            "max_tokens": 0,
-            "top_p": 0.98,
-            "timeout_seconds": 180,
-            "service_tier": "",
-            "reasoning_effort": "",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "mistral-medium-3-5",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "mistralai/mistral-medium-3-5",
-            "temperature": 0.15,
-            "max_tokens": 0,
-            "top_p": 0.98,
-            "timeout_seconds": 180,
-            "service_tier": "",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "mistral-small-3",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "mistralai/mistral-small-3.2-24b-instruct",
-            "temperature": 0.05,
-            "max_tokens": 0,
-            "top_p": 1,
-            "timeout_seconds": 180,
-            "service_tier": "",
-            "reasoning_effort": "",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "mistral-small-4",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "mistralai/mistral-small-2603",
-            "temperature": 0.1,
-            "max_tokens": 0,
-            "top_p": 0.98,
-            "timeout_seconds": 180,
-            "service_tier": "",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "nemotron-3-ultra",
-            "base_profile": "",
-            "backend": "openrouter",
-            "endpoint": "",
-            "model": "nvidia/nemotron-3-ultra-550b-a55b",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 180,
-            "service_tier": "flex",
-            "reasoning_effort": "high",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        },
-        {
-            "id": "rakestrawhome-gemma-4-31b",
-            "base_profile": "",
-            "backend": "rakestrawhome",
-            "endpoint": "",
-            "model": "google/gemma-4-31b-it",
-            "temperature": 0,
-            "max_tokens": 0,
-            "top_p": 0,
-            "timeout_seconds": 0,
-            "service_tier": "",
-            "reasoning_effort": "",
-            "api_key_env": "",
-            "api_key_required": false,
-            "extra_params": null
-        }
-    ]
-}
Author	SHA1	Message	Date
Eric Rakestraw	d79f1e9562	Prepare the v0.10.0 release	2026-09-22 14:06:35 +00:00
Eric Rakestraw	c8e4abcdbd	Complete profile policy integration review	2026-09-22 12:33:29 +00:00
Eric Rakestraw	6ce54c1d79	Document catalog profile compatibility	2026-09-22 12:31:50 +00:00
Eric Rakestraw	2356f7c73d	Adopt published version two catalogs	2026-09-22 12:26:22 +00:00
Eric Rakestraw	ba1e85a805	Add Promptkit-owned profile definitions	2026-09-22 12:23:07 +00:00
Eric Rakestraw	4c3828857c	Reserve Promptkit catalog profile names	2026-09-22 12:17:41 +00:00
Eric Rakestraw	02fd09955d	Record published catalog versions	2026-09-22 12:15:41 +00:00
Eric Rakestraw	7389410966	Record catalog contract preparation	2026-09-22 12:11:24 +00:00
Eric Rakestraw	3bc624ec3f	Plan the profile policy implementation	2026-09-22 12:06:24 +00:00
Eric Rakestraw	e5870453f9	Close gaps in public boundary checks	2026-09-22 11:40:25 +00:00
Eric Rakestraw	06251e385e	Record the completed public facade refactor	2026-09-22 04:50:40 +00:00
Eric Rakestraw	722b5ddf59	Add public facade boundary checks	2026-09-22 04:48:58 +00:00
Eric Rakestraw	47bc9a6655	Move option source construction into the internal engine	2026-09-22 04:44:41 +00:00
Eric Rakestraw	bd2b7b1862	Move engine composition into the internal engine package	2026-09-22 04:34:36 +00:00
Eric Rakestraw	c892eacb65	Move the memory profile repository into the profile package	2026-09-22 04:30:02 +00:00
Eric Rakestraw	ff73104f7e	Record the public facade compatibility baseline	2026-09-22 04:26:36 +00:00
Eric Rakestraw	7a858c2365	Plan the public facade refactor	2026-09-22 04:21:13 +00:00
Eric Rakestraw	e4540aa619	Plan the public facade refactor and profile policy updates	2026-09-22 04:13:52 +00:00