Add offline proposal assessment observation example

docs/development.md

@@ -40,7 +40,7 @@ Start with:
 | 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. |
-| Maintained example | The [example](../examples/go-library/prepare/main.go), [consumer guide](consumers/pkg-promptkit.md), [framework format reference](formats.md), and [documentation policy](policy/documentation.md). |
+| Maintained example | The [preparation](../examples/go-library/prepare/main.go), [execution](../examples/go-library/run/main.go), and [observation](../examples/go-library/observe/main.go) examples, [consumer guide](consumers/pkg-promptkit.md), [framework format reference](formats.md), and [documentation policy](policy/documentation.md). |
 | Documentation | The [documentation policy](policy/documentation.md) and canonical owner of every affected contract. |
 | Release preparation or publication | The [release policy](policy/release.md) and [release procedure](release.md). |
 
@@ -59,7 +59,7 @@ release-candidate checks have one executable entry point from the repository roo
 ```
 
 The [script](../scripts/release-check.sh) owns the executable checks:
-race-enabled tests, vet, both offline consumer examples with semantic output
+race-enabled tests, vet, the three offline consumer examples with semantic output
 assertions, tracked Go formatting, local Markdown links, module/workspace
 hygiene, whitespace, and the credential-pattern scan. It does not publish,
 change files, validate release-note structure, or retire roadmaps. It requires Go,

docs/internal/overview.md

@@ -14,6 +14,7 @@ contributor workflow and validation.
 | Root `promptkit` package | Provides the supported engine facade, source, backend-registration, and injection options, public request, result, prompt-inspection, profile-inspection, and ordinary-run observation values, opaque prepared-execution handles, profile construction, extension interfaces, value conversion, redacted formatting, and typed capacity and generation error mapping. | [Package GoDoc](../../doc.go), [observations](../../observations.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) |
+| `examples/go-library/observe` | Demonstrates offline built-in HTTP retry and synchronous metadata observation across structured proposal and assessment runs using embedded sources, two profiles on one finite backend, and an application decision. It is not a public library package. | [Example program](../../examples/go-library/observe/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) |

docs/policy/testing.md

@@ -64,13 +64,15 @@ Introducing hosted CI later would supplement, not silently redefine, this
 documented validation model.
 
 Full release-candidate validation includes race-enabled package tests, explicit
-static analysis, and execution with automated semantic checks of both maintained
+static analysis, and execution with automated semantic checks of the three maintained
 offline consumer examples. The test run builds the packages; the examples
 also exercise ordinary compilation. Separate ordinary tests and a standalone
 build are not additional release gates. Ordinary tests remain useful during
 development. The preparation example protects assembled preparation and
 inspection behavior. The execution example separately protects assembled
-`Run`, injected-client, validation, usage, and result behavior.
+`Run`, injected-client, validation, usage, and result behavior. The observation
+example protects assembled built-in retries, structured proposal and assessment
+runs, and application-owned interpretation of metadata.
 
 Tests in the default suite must be deterministic, offline, and independent of
 real credentials. They must not invoke paid APIs, use live network
@@ -96,7 +98,7 @@ Use each test type where it protects a distinct risk:
   interaction, while replacing live or nondeterministic external boundaries.
 - External-package root tests exercise the public facade as a Go consumer,
   while internal package tests own focused implementation behavior.
-- The maintained offline preparation and execution examples protect distinct
+- The maintained offline preparation, execution, and observation examples protect distinct
   representative assembled consumer workflows without contacting a model
   provider.
 - Fixtures should be minimal, synthetic, versioned with the behavior they

docs/roadmap/implementation.md

@@ -451,6 +451,8 @@ Run `go test -race -vet=off ./...` and `go vet ./...`; commit the verified scope
 
 ## Stage 11 — Add The Offline Proposal And Assessment Example
 
+**Completed:** 2026-09-23.
+
 Add `examples/go-library/observe` with embedded prompt/schema assets, two
 application-owned profiles sharing a finite custom backend, and one engine.
 Use a controlled RoundTripper under the built-in client: return one eligible