Merge branch 'codex/simp-unify-agent-session-id' into codex/simp-ui-identity-residue

# Conflicts:
#	docs/event-producer-consumer.md
#	docs/module-graph.md

docs/rfc/implemented/simplification/2026-07-04-fold-stdio-ui-helper.md

@@ -10,7 +10,7 @@ The boundary bought package metadata, workspace and tsconfig references, module-
 
 ## Decision
 
-The `stdio-chat` module now lives inside `dsh-stdio-agent` with its runtime seam. Per-file tests cover EOF, rendering, disposal, and piped-versus-TTY behavior without replacing process globals. It retains the named Cordis plugin export shape consumed by the app; an `unwrapExports` assertion and keyless Loader smokes guard both the package and composed entry paths.
+The helper lives in `@deepseek-ai/dsh-stdio` as the terminal-channel plugin (`packages/ui/stdio/src/index.ts`): `createStdioChat`, its `StdioRuntime` test seam, and its unit tests (`packages/ui/stdio/tests/stdio.spec.ts`, `readline.spec.ts`) moved with it, so EOF handling, rendering, disposal, and piped-vs-TTY behavior stay unit-covered under the per-file coverage gate without hijacking process globals. The module keeps the named `name`/`inject`/`Config`/`apply` export shape — the contract the app's `ctx.plugin(uiStdio, …)` mount consumes — and the keyless Loader-path smokes in `examples/echo-agent` and `examples/coding-agent` keep proving the composed tree boots through the real Loader (the stdio package's plugin-shape unit suite pins the explicit `unwrapExports` assertion, since a bundle without `inject` would boot past a stray default rather than crash).
 
 The `packages/support/ui-stdio` package is gone: manifest, tsconfig references, module-graph rows, and README rows deleted; the doc comments that named the package (the example e2e module docs, `packages/README.md`, the support and todo READMEs, [the ui group README](../../../../packages/ui/README.md)) describe the in-package module.
 

docs/rfc/implemented/simplification/2026-07-12-drop-unconsumed-skill-provider-events.md

@@ -0,0 +1,27 @@
+# RFC: Drop unconsumed skill provider events
+
+Status: implemented
+
+## Problem
+
+Two skill-registry notifications are produced but have no production listener. The generated producer/consumer matrix and exact event-name searches find only declarations, emit sites, tests, generated catalogs, and prose for `skill/provider-added` and `skill/provider-removed`.
+
+Skill discovery reads the current provider map on demand, provider registration synchronously clears completed catalogs, and the post-await revision check prevents stale discovery from entering the cache. No sibling plugin waits for a skill provider through these events, unlike the live `subagent/provider-added` consumer that tolerates concurrent sibling loading.
+
+`tools/change` and `system-prompt/change` are explicitly outside this proposal. Existing simplification decisions retain them as intentional observation points for live tool and prompt UIs, and self-referential mounted plugins already use `tools/change`. This proposal also leaves `subagent/provider-added`/`removed` unchanged because `tool-subagent` has a production lifecycle consumer.
+
+## Decision
+
+The skill registry declares and emits no provider-membership events. Provider registration and disposal remain direct effect-owned state changes that synchronously invalidate completed catalogs; lookup and discovery read the current provider map on demand. Tests observe cleanup through provider lookup and collected output rather than lifecycle notifications.
+
+The generated event catalog, API catalog, and producer/consumer matrix omit the deleted notifications. The skill-system RFC and package documentation describe registration through its direct effect-owned state and cache-invalidation contract.
+
+## Alternatives considered
+
+**Keep skill-provider notifications for future plugins.** A third-party plugin could observe provider availability, but direct provider registration and on-demand lookup are the extension contract; no current consumer needs a push signal. If a future sibling-load race appears, it can introduce a notification with the identity and readiness semantics that consumer requires, as the subagent registry did.
+
+## Consequences
+
+The generated event matrix contains no row for `skill/provider-added` or `skill/provider-removed`. Skill discovery, direct runtime registration, provider effect rollback/disposal, cache invalidation, and registry lookup cleanup remain; listener-triggered rollback disappears with the events. `tools/change`, `system-prompt/change`, and the consumed subagent provider lifecycle events are unchanged.
+
+Pre-release consumers lose skill-provider observation points while retaining both ways to contribute skills: direct runtime registration and provider registration. A future consumer that needs live provider availability must add a purpose-built notification with the identity and readiness semantics it actually requires.

docs/rfc/implemented/simplification/2026-07-12-prune-unused-web-seam-fields.md

@@ -0,0 +1,25 @@
+# RFC: Prune unused web seam fields
+
+Status: implemented
+
+## Problem
+
+The web capability carries request/result/status values that every shipped implementation populates but no production consumer reads. `WebSearchResult.providerId` and `query` and `WebFetchResult.providerId` are result echoes; `tool-web` formats only content/sources/truncation or final URL/status/body/truncation, and no other runtime reads them. Search providers return `WebProviderStatus.reason`, but resolution checks only `available` and intentionally emits a generic unavailable diagnostic.
+
+`WebFetchRequest.timeoutMs` is likewise never set by a production caller. `tool-web` supplies only the URL, uses the tool definition's timeout plus `exec.signal` for the caller deadline, and relies on the local provider's configured default as a backstop. The unused per-request override forces `web-fetch-local` to expose `maxTimeoutMs`, clamp two timeout sources, and document/test precedence no product path can select. `WebExecContext` is another one-field wrapper: every caller allocates `{ signal }` and every provider immediately unwraps `exec?.signal`; no second execution-control field exists.
+
+## Decision
+
+The web seam omits the search/fetch `providerId` result echoes and search `query` echo; callers already own the request and provider selection. Providers expose availability as a boolean-returning method. Fetch requests have no per-request timeout or `maxTimeoutMs` clamp; the local provider retains its configurable default timeout and the tool retains its own deadline. Provider methods receive a direct optional `AbortSignal` instead of a one-field `WebExecContext` wrapper.
+
+All web implementations and the model-facing tool use the smaller contract. The interface/implementation/consumer package split, provider selection, source citations, final-URL/status data, truncation reporting, and safety limits remain.
+
+## Alternatives considered
+
+**Keep self-describing results, per-request deadlines, and an extensible execution-context object.** Result echoes can help generic telemetry, a request timeout can help trusted programmatic callers, and the wrapper leaves room for future controls. No such consumer/second field exists; carrying duplicate identity, a second deadline policy, and wrap/unwrap plumbing through every provider makes the current contract harder to implement and explain. If telemetry or per-call budget control arrives, it should define which deadline wins, where provider identity is observed, and whether multiple controls justify a context object.
+
+## Consequences
+
+Every retained web request/result field is consumed by production code or required to execute the provider request. Tool-visible search/fetch output, provider fallback, abort behavior, the configured timeout backstop, truncation, and citations remain covered without a request-timeout precedence branch or execution-context wrapper.
+
+Pre-release programmatic callers lose result provenance echoes and per-request fetch deadlines. The provider still has a deployment-configurable timeout and respects cancellation, so the simplification removes configurability rather than a safety bound.