Merge remote-tracking branch 'origin/master' into worktree/agent-execution-context-rfc

# Conflicts:
#	docs/architecture.md
#	docs/config-catalog.md
#	docs/cordis-catalog/services.md
#	docs/module-graph.md
#	examples/coding-agent/tests/code-mode.e2e.ts
#	packages/context/workspace-context/tests/workspace-context.spec.ts
#	packages/core/README.md
#	packages/core/agent-loop/README.md
#	packages/core/agent-loop/tests/agent.spec.ts
#	packages/core/agent-loop/tests/cancel.spec.ts
#	packages/core/agent-loop/tests/config-session-id.spec.ts
#	packages/core/agent-loop/tests/contract-regressions.spec.ts
#	packages/core/agent-loop/tests/coverage-edges.spec.ts
#	packages/core/agent-loop/tests/interception.spec.ts
#	packages/core/agent-loop/tests/loop.spec.ts
#	packages/core/agent-loop/tests/properties.spec.ts
#	packages/core/agent-loop/tests/request-cache.e2e.ts
#	packages/core/agent-loop/tests/request-reconstruction.spec.ts
#	packages/core/agent-loop/tests/resume.spec.ts
#	packages/core/agent-loop/tests/scope-lifecycle.spec.ts
#	packages/core/agent-loop/tests/tool-calls.spec.ts
#	packages/core/agent-loop/tests/tool-order.spec.ts
#	packages/core/agent-loop/tests/turn-stop.spec.ts
#	packages/workflow/workflow-workerthread/tests/workflow-workerthread.e2e.ts
#	website/zh-CN/api/harness/agent-loop.md

docs/rfc/implemented/architecture/2026-06-11-content-block-vocabulary.md

@@ -23,4 +23,4 @@ In-session context injection (`context/message`, `steering/message`) renders as
 - Multimodal blocks return only with coordinated adapter, UI, and compaction support; see [the drop-image RFC](../simplification/2026-07-04-drop-image-content-block.md).
 - Cache hints and assistant prefill remain absent until a shipping adapter can honor them; see the [producer-less variants](../simplification/2026-07-04-prune-producerless-vocabulary-variants.md) and [inert request knobs](../simplification/2026-07-04-drop-inert-request-knobs.md) RFCs.
 - Every adapter pays a translation cost; the first real adapters have since validated the streaming protocol, and new adapters should continue proving their provider-specific mapping in adapter-local tests.
-- IDs that cross package boundaries are branded (`CallId`, `SessionId`, `AgentId`) — nominal typing at zero runtime cost.
+- IDs that cross package boundaries are branded (`CallId`, the shared agent/session `SessionId`) — nominal typing at zero runtime cost.

docs/rfc/implemented/architecture/2026-06-14-session-persistence.md

@@ -21,7 +21,7 @@ Key choices recorded here because they are durable, contested, and surprising:
 - **Append-only; a crashed turn is closed, never truncated.** Events through a flushed `turn/end` are never rewritten, and the loop flushes only at turn end. Because one interrupted turn may contain substantial valid work, `load` preserves its contiguous, parseable events and appends error results for unanswered tool calls, a missing `step/end`, and `turn/end` with `{ kind: 'interrupted' }`. The synthetic results keep resumed provider transcripts valid. Only an incomplete final record is discarded; a parse error or sequence gap at or before the last real `turn/end` is corruption and makes the session unloadable.
 - **File backend canonical, DB backend a proven drop-in.** `SessionEvent` maps 1:1 onto a row `(session_id, seq, type, time, data)` — `append` is INSERT (in a transaction asserting the contiguous-seq contract), `load` is SELECT … ORDER BY seq. `dsh-session-persistence-sqlite` is exactly this: a `SessionPersistence` subclass with no interface change (opencode runs this exact shape on SQLite/WAL), and it passes the same `runPersistenceContract` suite as the JSONL backend — so the contract holds both backends to identical semantics (lazy materialization, interrupted-turn close on load, contiguous-seq), expressed once over file bytes and once over rows.
 - **Metadata is out-of-log.** Format version, cwd, and lineage are storage concerns, not replayable conversation state, so they live in a `SessionHeader` owned by `dsh-session` and attached to a `Session` via a new readonly `session.header` — never in `SessionEventMap`, never reaching `deriveMessages()`. The alternative (a merge-extensible `session/meta` event as log line 0) was rejected: an in-log event would ride along with a seeded/forked session for free, but metadata is not replayable state, so the explicit out-of-log header seam is the cleaner cost. (The header was originally split into an immutable `SessionHeader` plus a mutable `SessionSummary` whose union was `SessionMeta`; the mutable summary was later removed as dead state — see [Drop the mutable session summary](../simplification/2026-06-19-drop-mutable-session-summary.md).)
-- **`ctx.agents.create()` and `ctx.agents.resume()` are async factories; resume additionally crosses the persistence boundary.** `ctx.agents.resume({ resumeSessionId })` awaits `ctx.sessionPersistence.load`, recreates the live session with the loaded events (so `lastTurnNumber`/`deriveMessages` continue), and starts a fresh agent on the resumed id (NOT `${agentId}-session`). The agent-loop does NOT hard-inject `sessionPersistence` (that would pend non-persistent demos forever); `resume` rejects with a clear error when it is absent.
+- **`ctx.agents.create()` and `ctx.agents.resume()` are async factories; resume additionally crosses the persistence boundary.** `ctx.agents.resume({ resumeSessionId })` awaits `ctx.sessionPersistence.load`, recreates the live session with the loaded events (so `lastTurnNumber`/`deriveMessages` continue), and registers the fresh agent under the exact resumed id. The agent-loop does NOT hard-inject `sessionPersistence` (that would pend non-persistent demos forever); `resume` rejects with a clear error when it is absent.
 
 ## Alternatives considered
 

docs/rfc/implemented/architecture/2026-06-18-agent-lifecycle-and-ownership-seams.md

@@ -12,28 +12,30 @@ Three seams: the queue-aware cancel, the `AgentHandle` disposer, and the bash ow
 
 ### 1. Queue-aware `Agent.cancel(reason?)`
 
-`cancel()` is the single public stop primitive. It clears queued and steering input, aborts an in-flight step, and arms a turn-scoped marker checked at each turn boundary. A queued prompt therefore cannot start after cancellation or absorb later input. `whenIdle()` waits for post-cancel quiescence, and ACP `session/cancel` maps to this method. An idle cancel does not arm the marker.
+A new `cancel()` verb on the `Agent` interface — the single public stop primitive. (It originally shipped alongside a narrower step-only `abort()`; that verb was later removed as unused, leaving `cancel()` the only public way to stop work.) It clears the inbox's queued + steering FIFOs, aborts the in-flight step if any, and drives a **turn-scoped cancellation marker** the driver loop checks at every turn-decision point — so a prompt that is queued-but-not-yet-started never runs, a cancel landing in the pre-step / continuation window drops the about-to-run turn (ending it `aborted`), and a later prompt cannot be batched into the cancelled turn. `whenIdle()` reaches post-cancel quiescence. ACP `session/cancel` maps to `cancel()`. The marker is armed ONLY when there is something to cancel, so an idle no-op cancel cannot strand the next prompt.
 
 ### 2. `AgentHandle` async disposer
 
-`ctx.agents.create`/`resume` and `AgentFactory` return `AgentHandle = { agent, dispose() }`. Disposal is a consumer capability; an observer holding only `Agent` cannot tear it down. The caller fiber and factory provider also own the instance, and every path shares one memoized teardown: stop the loop, await quiescence and flushes, detach the agent and session, then unwind its scope. IDs become reusable when their registry entries detach. Config-created agents belong to the loop fiber; ACP stores and disposes each session handle.
+`ctx.agents.create`/`resume` (and the `AgentFactory` interface) return `AgentHandle = { agent: Agent; dispose(): Promise<void> }`. The disposer is a **consumer capability** — a registry observer holding only the bare `Agent` cannot tear it down. The caller fiber and registered factory provider are structural co-owners: caller unload enforces structured ownership, while provider unload must stop old instances whose scoped dependency surface resolves through that provider. All three paths reach the same memoized teardown: stop the loop, await its exit and idle flushes (true quiescence, not just the `disposed` status flip), detach the agent, detach its session, and unwind its scope. Each public ID becomes reusable when its exact registry entry detaches; there is no separate reservation-release phase. Config-created agents are already owned by the `AgentLoop` fiber (the handle is discarded). ACP holds each session's disposer in its `SessionRecord` and runs it on disconnect/teardown, so a bare client disconnect leaves no registered agent and no session-store entry — even when `session/load` races teardown (the just-resumed handle is disposed before the closed-guard throw).
 
-Teardown order is load-bearing for durability. The session lifecycle and loop share one composite Cordis effect so LIFO disposal stops the loop and awaits `agent.done` before detaching the session. Sibling effects would dispose concurrently and could remove append hooks before the closing flush. Disposal notifications are contained so they cannot interrupt the chain.
+**Teardown ORDER is load-bearing for durability**, and the implementation folds the session lifecycle into the agent's SINGLE composite cordis effect (`SessionStore.prepare`/`enter`/`announce`, replacing a sibling-effect split). A fiber unload disposes sibling effects concurrently (`Promise.all`), which would race removing the session store's append publication hooks against the loop's closing `session/flush` and drop the closing `turn/end`; inside one effect the disposers run as an ordered LIFO chain (loop stopped + `await agent.done` BEFORE the session detaches), so the loop's final flush is captured on BOTH the handle's `dispose()` and a fiber unload. The contained `agent/disposed` and `session/disposed` notifications cannot reject the chain or skip later teardown.
 
 ### 3. Bash owner token in the seam
 
-Background task ownership belongs to the executor. `BashExecSpec.owner` carries an optional opaque token, `ownerOf(id)` reads it, and `dsh-tool-bash` stamps the calling session token at start. `bash_output` and `bash_kill` reject mismatched callers; completion notices locate the live agent by session token through the registry. Keeping ownership on the task preserves the fence across tool-plugin reloads. The completion listener remains effect-scoped, so a notice that settles during the reload gap may still be dropped.
+Background-task ownership moved from a `tool-bash` plugin-local `Map<string, Agent>` into the executor. `BashExecRequest` gains an optional `owner?: string`; the resolved `BashExecSpec` carries it as required-but-nullable `owner: string | undefined` (a forgotten owner is a visible `undefined`, never a silently-absent property). The executor stores the token on its task and exposes it via a new `BashExecutor.ownerOf(id): string | undefined` seam (NOT on the public `BashTask` — one read path, no redundant API). `tool-bash` deletes its `Map` entirely: it stamps `exec.agent?.id` (the shared registry/session id) as the owner at `start`, and `bash_output`/`bash_kill` compare `ctx.bash.ownerOf(id)` to the caller's token with `!== undefined` semantics (an empty-string token is still a real owner). The completion notice finds the live agent by scanning `ctx.get('agents')?.list()` for `agent.id === ownerToken` (read via `ctx.get` — `onTaskDone` runs on the bash fiber, a foreign fiber, where the `ctx.agents` proxy would throw). Because ownership now lives on the task in the executor (disposed with the `dsh-bash` fiber), it SURVIVES a `tool-bash` HMR reload — closing the old `XXX(tool-bash-owner-hmr)` gap. (The `onTaskDone` listener is still effect-scoped to `tool-bash`'s `apply`, so a completion landing during the reload gap still drops its one notice — the pre-existing reload-gap drop — but the ownership fence itself is HMR-proof.)
 
 ## Verification
 
-- ACP disconnect or session close leaves no registered agent or session-store entry, including when `session/load` races teardown.
-- Cancelling before a queued prompt starts prevents that prompt from running or absorbing the next prompt.
-- Reloading `dsh-tool-bash` does not let another session read or kill an existing background task because ownership remains on the executor.
-- Config-created agents remain loop-fiber-owned, so non-ACP demos need not manage handles explicitly.
+These invariants hold and are pinned by tests:
+
+- ACP disconnect/session close leaves no registered agent AND no session-store entry for that session, even when `session/load` races teardown.
+- `session/cancel` before a queued prompt starts prevents that prompt from running and cannot batch the next prompt into the cancelled turn.
+- A `tool-bash` HMR reload does NOT make an existing background task readable or killable by a different session (ownership survives on the executor).
+- Existing non-ACP demos still work without managing handles explicitly; config-created agents remain owned by the `AgentLoop` plugin fiber.
 
 ## Session owner tokens are unique among live agents
 
-The bash owner token relies on `session.header.id` being unique among live agents. Concurrent same-ID operations may prepare privately, but `SessionStore.enter()` rejects duplicate publication and the losing transaction rolls back. `tool-bash` owns the comparison policy; the bash seam stores an opaque `owner` string without interpreting it.
+The bash owner-token comparison relies on the shared `Agent.id`/`SessionId` being unique among live agents. Concurrent same-ID operations may both prepare privately, but publication enters the session and agent in order; `SessionStore.enter()` rejects a duplicate live session id, and every losing transaction rolls its private state back. A programmatic caller therefore cannot publish two live agents with one session token. The access *policy* (token comparison) stays in `tool-bash` (the consumer); the bash seam stores only an opaque `owner` string and never interprets it — the correct interface/implementation/consumer split.
 
 ## Alternatives considered
 

docs/rfc/implemented/architecture/2026-06-20-branded-ids.md

@@ -4,23 +4,23 @@ Status: implemented
 
 ## Problem
 
-The harness already brands three identifiers — `CallId` (`packages/llm/llm/src/brand.ts`), `SessionId` (`packages/core/session/src/types.ts`), and `AgentId` (`packages/core/agent/src/types.ts`) — using the `Branded<B> = string & { readonly [BRAND]: B }` machinery (owned by the type-only `@deepseek-ai/dsh-brand` package at `packages/util/brand/` — see its [README](../../../../packages/util/brand/README.md)) and a zero-cost cast factory per type. `dsh-brand` also states the governing policy: *"Branding is for ids that cross package boundaries and could plausibly be confused; not every string needs a brand."* That policy is right; the problem is that it is only half-applied. Two gaps let a structurally-identical-but-semantically-wrong string slip through the type checker today.
+The harness brands `CallId` (`packages/llm/llm/src/brand.ts`) and the shared agent/session `SessionId` (`packages/core/session/src/types.ts`) using the `Branded<B> = string & { readonly [BRAND]: B }` machinery (owned by the type-only `@deepseek-ai/dsh-brand` package at `packages/util/brand/` — see its [README](../../../../packages/util/brand/README.md)) and a zero-cost cast factory per type. `dsh-brand` also states the governing policy: *"Branding is for ids that cross package boundaries and could plausibly be confused; not every string needs a brand."* That policy is right; the problem is that it is only half-applied. Two gaps let a structurally-identical-but-semantically-wrong string slip through the type checker today.
 
-**Gap 1 — unbranded IDs in the bash seam.** `BashTask.id` and every executor/tool boundary used bare `string`, even though the generated value has the same `name-N` shape as default session ids. The model also returns this value through `task_id`, so confusing task and session ids was both type-correct and reachable.
+**Gap 1 — unbranded cross-boundary IDs in the bash seam.** The background-task id is a plain `string`: `BashTask.id: string` (`packages/bash/bash/src/types.ts`), carried as `string` through the whole executor seam (`BashExecutor.get`/`ownerOf`/`readOutput`/`kill(id: string)` in `packages/bash/bash/src/index.ts`) and validated/passed as `string` by the model-facing tools (`validateTaskId`, `assertTaskAccess`, the `task_id` schema arg in `packages/bash/tool-bash/src/index.ts`). It is generated by a per-executor counter — `` `bash-${this.nextTaskId++}` `` in `packages/bash/bash-local/src/index.ts` — which gives it **exactly the same `name-N` shape as `SessionId`'s default** (`` `session-${++counter}` `` in `packages/core/session/src/index.ts`). A bash task id and a session id are trivially swappable at a call site and the compiler says nothing. This is the headline case the user asked about, and it is a model-facing id (the model passes `task_id` back to `bash_output`/`bash_kill`), so a confusion here is reachable from untrusted input.
 
-The bash **owner token** is the related sub-case: `BashExecRequest.owner?: string` and `BashExecSpec.owner: string | undefined` (`packages/bash/bash/src/types.ts`) are documented as a deliberately *opaque* isolation key, but in every live caller the value IS the owning agent's `session.header.id` (`callerToken = (exec) => exec.agent?.session.header.id` in `packages/bash/tool-bash/src/index.ts`) — i.e. a `SessionId` wearing a `string` disguise. It is compared for access control (`owner !== callerToken(exec)`), so a mismatched-but-well-typed string here is a cross-session isolation bug the type system currently cannot catch. This is the same `session.header.id`-as-owner alias that the [unify-the-agent-id-and-the-session-id](../../proposed/simplification/2026-06-20-unify-agent-and-session-id.md) proposal calls the "bash owner-token alias hole".
+The bash **owner token** is the related sub-case: `BashExecRequest.owner?: string` and `BashExecSpec.owner: string | undefined` (`packages/bash/bash/src/types.ts`) are documented as a deliberately *opaque* isolation key, but in every live caller the value IS the owning agent's shared `Agent.id`/`SessionId` (`callerToken = (exec) => exec.agent?.id` in `packages/bash/tool-bash/src/index.ts`) wearing a different seam-local name. It is compared for access control (`owner !== callerToken(exec)`), so a mismatched-but-well-typed string here is a cross-session isolation bug the type system currently cannot catch. This is the shared id alias covered by the [unified agent/session identity decision](../simplification/2026-06-20-unify-agent-and-session-id.md).
 
-**Gap 2 — erosion of existing brands.** `CallId`, `SessionId`, and `AgentId` became bare strings in registry maps, public lookup parameters, ACP session tracking, and the persistence coordinator. Dropping a brand at a lookup boundary defeats its main protection.
+**Gap 2 — brand erosion at the seams of the *already-branded* IDs.** Even `CallId` and `SessionId` decay back to bare `string` at exactly the places confusion is most likely: registry/store key types and public method params. Representative sites include the session store, the agent registry (both keyed by the shared `SessionId`), `ToolPresenter`'s call-id map, ACP's session-id records and loading set, and the persistence coordinator. A brand that is dropped at a collection key buys nothing on lookups — the value of the existing brands is partly unrealized.
 
 ## Decision
 
 A type-only change. Brands are zero-cost casts; nothing about runtime behavior, serialization, comparison, or the wire format changes. The work is in three parts, all honoring the existing "not every string" policy.
 
-- **Brand the bash task id.** Add `BashTaskId = Branded<'BashTaskId'>` plus its same-named factory in `packages/bash/bash/src/types.ts` (the package that *owns* the id), importing `Branded` from `@deepseek-ai/dsh-brand` exactly as `SessionId`/`AgentId` already do. The brand primitive lives in the dependency-free `dsh-brand` utility package precisely so `dsh-bash` can brand its ids by depending on it alone — it never pulls in `dsh-llm` (or `dsh-session`) just to reach `Branded`. Thread it through `BashTask.id`, the `BashExecutor` seam methods (`get`/`ownerOf`/`readOutput`/`kill`), the generation site in `dsh-bash-local` (brand the counter output once, at creation), and the `dsh-tool-bash` validate/access surface (`validateTaskId` returns a `BashTaskId`; `task_id` is branded at the tool boundary where the model's string arrives).
+- **Brand the bash task id.** Add `BashTaskId = Branded<'BashTaskId'>` plus its same-named factory in `packages/bash/bash/src/types.ts` (the package that *owns* the id), importing `Branded` from `@deepseek-ai/dsh-brand` exactly as `SessionId` does. The brand primitive lives in the dependency-free `dsh-brand` utility package precisely so `dsh-bash` can brand its ids by depending on it alone — it never pulls in `dsh-llm` (or `dsh-session`) just to reach `Branded`. Thread it through `BashTask.id`, the `BashExecutor` seam methods (`get`/`ownerOf`/`readOutput`/`kill`), the generation site in `dsh-bash-local` (brand the counter output once, at creation), and the `dsh-tool-bash` validate/access surface (`validateTaskId` returns a `BashTaskId`; `task_id` is branded at the tool boundary where the model's string arrives).
 
-- **Mint a distinct `OwnerToken` brand.** Add `OwnerToken = Branded<'OwnerToken'>` in `packages/bash/bash/src/types.ts`; type `BashExecRequest.owner` / `BashExecSpec.owner` / `BashExecutor.ownerOf` as `OwnerToken | undefined`. The `dsh-tool-bash` consumer casts the agent's `session.header.id` (a `SessionId`) into an `OwnerToken` at the boundary — the one place the two vocabularies meet. The bash seam never imports `dsh-session`. (Rationale in the next section.)
+- **Mint a distinct `OwnerToken` brand.** Add `OwnerToken = Branded<'OwnerToken'>` in `packages/bash/bash/src/types.ts`; type `BashExecRequest.owner` / `BashExecSpec.owner` / `BashExecutor.ownerOf` as `OwnerToken | undefined`. The `dsh-tool-bash` consumer casts the agent's shared `id` (`SessionId`) into an `OwnerToken` at the boundary — the one place the two vocabularies meet. The bash seam never imports `dsh-session`. (Rationale in the next section.)
 
-- **Stop the brand erosion.** Propagate the existing brands to the `Map` key types and public method params listed under Gap 2 — `Map<SessionId, Session>`, `get(id: SessionId)`, `Map<AgentId, Agent>`, `Map<CallId, …>`, the ACP `SessionRecord.sessionId: SessionId` surface, the coordinator's `Map<SessionId, …>`. This is the larger mechanical share of the diff and the part that makes the *existing* brands actually load-bearing on lookups, not just on the struct fields.
+- **Stop the brand erosion.** Propagate the existing brands to the `Map` key types and public method params listed under Gap 2 — `Map<SessionId, Session>`, `Map<SessionId, Agent>`, `get(id: SessionId)`, `Map<CallId, …>`, ACP's `SessionId` surface, and the coordinator's `Map<SessionId, …>`. This is the larger mechanical share of the diff and the part that makes the *existing* brands actually load-bearing on lookups, not just on struct fields.
 
 Illustrative shape (the factory pattern is identical to the three existing brands):
 
@@ -44,7 +44,7 @@ export function OwnerToken(id: string): OwnerToken {
 
 ### Why not typing `owner` as `SessionId`?
 
-The executor treats ownership as opaque and must not depend on the session model. A distinct `OwnerToken` preserves that boundary while preventing raw strings or task ids from being passed as owners. `dsh-tool-bash`, which owns the access policy, performs the single conversion from `SessionId`.
+The obvious shortcut is to type `owner` as `SessionId` directly — it always *is* one. We reject that. The bash executor seam is a capability seam (interface `dsh-bash`, implementation `dsh-bash-local`, consumer `dsh-tool-bash`) and its owner token is *documented as deliberately opaque*: the executor "never interprets it (no access policy lives in the seam — that is the consumer's job)" (`packages/bash/bash/src/types.ts`). Typing the seam's field as `SessionId` would import `dsh-session`'s vocabulary into a package that must not know what an owner token *means* — it would couple a generic execution backend to the session model and contradict the opaque-token design. A sandboxed or remote executor that replaces `dsh-bash-local` should not inherit a session dependency. The distinct `OwnerToken` brand keeps the seam decoupled: `dsh-bash` knows only "an owner is some opaque branded token," and the `dsh-tool-bash` consumer — which already decides the access policy — is the single boundary that casts its `SessionId` into an `OwnerToken`. The brand still delivers the safety win (you cannot pass a `BashTaskId` or a raw string where an owner is expected) without the coupling.
 
 ## Out of scope / possible extensions
 
@@ -58,10 +58,10 @@ Kept deliberately narrow per the "not every string needs a brand" policy. Each o
 
 ## Verification
 
-`BashTaskId` and `OwnerToken` are defined in `dsh-bash` and threaded through the executor, local implementation, and model-facing tool without adding a `dsh-session` dependency. Collections, public parameters, and exported signatures use the applicable brand for `CallId`, `SessionId`, `AgentId`, or `BashTaskId` rather than bare `string`; raw provider, ACP, and model inputs enter through the brand factory instead of scattered casts.
+The landed invariants: `BashTaskId` and `OwnerToken` are defined in `dsh-bash` and threaded end-to-end (executor seam, the `dsh-bash-local` generation site, the `dsh-tool-bash` model-facing surface) with no `dsh-bash` dependency on `dsh-session`; no collection keyed by an in-scope branded id (`CallId`/`SessionId`/`BashTaskId`) is keyed by bare `string`; public method params and exported signatures keep the brand; and brands are constructed via the cast factory at each boundary where a raw string enters (provider call id, ACP session id, model-supplied `task_id`), never as scattered `as` casts.
 
 ## Consequences
 
-- **Mechanical churn across two surfaces.** Propagating brands touches the bash seam (interface + impl + consumer) and the ACP session-id surface plus the persistence coordinator. The churn is broad but low-severity: a missed site is a compile error, not a silent bug. The change is observably type-only — no snapshot or e2e behavioral diff. It sits next to the [unify-the-agent-id-and-the-session-id](../../proposed/simplification/2026-06-20-unify-agent-and-session-id.md) proposal (both touch the session-id / owner-token boundary); if that proposal lands, `OwnerToken` still stays distinct from the unified id for the decoupling reason above.
+- **Mechanical churn across two surfaces.** Propagating brands touches the bash seam (interface + impl + consumer) and the ACP session-id surface plus the persistence coordinator. The churn is broad but low-severity: a missed site is a compile error, not a silent bug. The change is observably type-only — no snapshot or e2e behavioral diff. It sits next to the [unified agent/session identity decision](../simplification/2026-06-20-unify-agent-and-session-id.md) because both touch the session-id / owner-token boundary; `OwnerToken` stays distinct from the unified id for the decoupling reason above.
 - **Brands do not validate.** A brand is a confusability guard, not a correctness proof: a *wrong* session id that is still a well-formed string passes the type checker exactly as before. This RFC does not close that gap (see Out of scope) — it only stops the *category* error of passing the wrong *kind* of id.
 - **The "where to stop" line stays a judgment call.** Branding `BashTaskId` but not `ToolName`, `OwnerToken` but not `ModelId`, is a taste call about which strings "could plausibly be confused." Reasonable reviewers may want more or fewer; the policy in `brand.ts` is the tie-breaker, and this RFC errs toward the ids that are model-facing or used for access control.

docs/rfc/implemented/architecture/2026-06-30-event-domain-semantics.md

@@ -24,7 +24,7 @@ This vocabulary is the foundation for interception decisions, the durable `hook/
 
 **The boundary rule:** a durable, replayable fact is a `SessionEvent`; a live interception or a transient/live-object signal is an `agent`/`tools` Cordis event. A turn or step boundary is a durable fact, so it lives in the session log and is read off the `session/event` feed — it is NOT mirrored as an `agent/*` emit.
 
-**Applying the rule to the boundary twins:** all four boundary mirrors — `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end` — are **REMOVED**. No production consumer needs the live `Agent` at a boundary: the ACP bridge settles from `session/event` `turn/end` plus `agent/status`, and the only turn-mirror consumer (`dsh-ui-stdio`, a disposable test REPL) was migrated to render boundaries from `session/event`, recovering the short agent label from an `agent/created`→id map. The step mirrors were removed first (they had no consumer at all); the turn mirrors followed once ui-stdio was migrated — see [the remove-boundary-mirror-events RFC](../simplification/2026-06-20-remove-agent-boundary-mirror-events.md), which owns that decision. Removing the emits also simplifies the loop's `closeStep`/`closeTurn` (one append each, no paired emit).
+**Applying the rule to the boundary twins:** all four boundary mirrors — `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end` — are **REMOVED**. No production consumer needs the live `Agent` at a boundary: the ACP bridge settles from `session/event` `turn/end` plus `agent/status`, and the only turn-mirror consumer (`dsh-ui-stdio`, a disposable test REPL) renders boundaries from `session/event` while retaining its live target object for the fixed `main` label. The step mirrors were removed first (they had no consumer at all); the turn mirrors followed once ui-stdio was migrated — see [the remove-boundary-mirror-events RFC](../simplification/2026-06-20-remove-agent-boundary-mirror-events.md), which owns that decision. Removing the emits also simplifies the loop's `closeStep`/`closeTurn` (one append each, no paired emit).
 
 ## Consequences
 

docs/rfc/implemented/architecture/2026-07-05-subagent-provider-lifecycle-events.md

@@ -4,7 +4,7 @@ Status: implemented
 
 ## Problem
 
-[The prompt-variables RFC](2026-07-05-prompt-variables-and-tool-guidance-ownership.md) makes `dsh-tool-subagent` DERIVE its model-facing wording from its provider: `SubagentProvider.inheritsParentContext` (spawn/ACP `false`, fork `true`) drives both the tool description and the `prompt` parameter description (`providerWording`), so the fork tool stops lying about context inheritance. That fix created a cross-fiber data dependency: a tool's description is fixed at TOOL REGISTRATION (deliberately — the description is where tool-choice guidance lives), but the provider arrives on its own plugin fiber, on no particular schedule.
+[The prompt-variables RFC](2026-07-05-prompt-variables-and-tool-guidance-ownership.md) makes `dsh-tool-subagent` DERIVE its model-facing wording from its provider: `SubagentProvider.inheritsParentContext` (spawn/ACP `false`, fork `true`) drives both the tool description and the `prompt` parameter description, so the fork tool stops lying about context inheritance. That fix created a cross-fiber data dependency: a tool's description is fixed at TOOL REGISTRATION (deliberately — the description is where tool-choice guidance lives), but the provider arrives on its own plugin fiber, on no particular schedule.
 
 Resolving the provider at the tool plugin's `apply` time creates an implicit load-order requirement ("list the backend before the tool in cordis.yml"). That requirement fails because the Cordis Loader starts sibling entries concurrently and `Entry.init()` does not await activation: a delayed backend can leave the tool fiber failed even when listed first. The Loader offers no sibling-order guarantee — "async state is not synchronous state" ([defensive patterns](../../../defensive-patterns.md)).
 

docs/rfc/implemented/architecture/2026-07-08-agent-scope-contexts.md

@@ -60,8 +60,7 @@ The ordinary contributor pattern is to register the complete local world during
 
 ```js
 const handle = await ctx.agents.create({
-  agentId: AgentId('reviewer'),
-  sessionId: SessionId('reviewer-session'),
+  sessionId: SessionId('reviewer'),
   agentOptions: { model: 'model-name' },
   setup(agentCtx) {
     agentCtx.systemPrompt.section({

docs/rfc/implemented/feature/2026-06-14-acp-multi-session.md

@@ -8,11 +8,11 @@ An ACP editor can keep several conversations alive over one agent subprocess. A
 
 ## Decision
 
-The ACP bridge stores live sessions in `Map<SessionId, SessionRecord>` and keeps a `WeakMap<Agent, SessionId>` reverse index for agent-scoped callbacks. A record owns its agent handle, in-flight prompt, live tool-call presentation state, pending idle config switches, session cwd, and client capability snapshot. A separate loading-id set reserves each id before asynchronous resume so two pipelined loads cannot construct duplicate agents; distinct ids may load concurrently.
+The ACP bridge stores live sessions in `Map<SessionId, SessionRecord>`. Agent-scoped callbacks use `ownedRecord`: look up `agent.session.id` in that forward map and accept the record only when it owns the exact agent object, so a foreign same-id object cannot claim the session. A record owns its agent handle, in-flight prompt, live tool-call presentation state, pending idle config switches, session cwd, and client capability snapshot. A separate loading-id set reserves each id before asynchronous resume so two pipelined loads cannot construct duplicate agents; distinct ids may load concurrently.
 
 Every `session/event` and `agent/status` callback resolves the owning record before sending or settling anything. Each session permits one in-flight prompt independently. The prompt records a log watermark, captures its own `turn/start`, and settles only on the matching `turn/end`; a late end from a cancelled prior turn cannot resolve a newer prompt. `session/cancel` addresses one record and calls only that agent's queue-aware cancel path.
 
-Permission ownership uses the same reverse index. The ACP `approval/request` answerer prompts only the editor session that owns the requesting agent and delegates foreign requests. User-interaction elicitations likewise route by agent ownership. Per-session sandbox and approval config values fold only that session's events, with pending idle switches stored on that record until the next turn anchors them.
+Permission ownership uses the same exact-agent check against the forward map. The ACP `approval/request` answerer prompts only the editor session that owns the requesting agent and delegates foreign requests. User-interaction elicitations likewise route by agent ownership. Per-session sandbox and approval config values fold only that session's events, with pending idle switches stored on that record until the next turn anchors them.
 
 Background bash tasks carry an opaque owner token equal to the owning session id. `bash_output` and `bash_kill` compare the caller's token with the executor's task ownership before reading or killing; a predictable task id alone grants no access. Ownership is stored with the executor task, so a tool plugin reload does not erase it.
 

docs/rfc/implemented/feature/2026-06-18-compaction-capability-seam.md

@@ -22,7 +22,7 @@ Per the [capability-seams RFC](../../implemented/architecture/2026-06-13-capabil
 
 ### The contract depends on `dsh-session` and `dsh-llm` — a deliberate deviation
 
-The capability-seams RFC states the interface package "depends only on cordis" (true of `dsh-bash`, whose vocabulary is self-contained). Compaction **cannot** honor that: its verbs are defined *over* a `Session` (`compactRegion(session, start, end)`) and its output *is* the content vocabulary (`CompactionResult.summary: ContentBlock[]`). There is no way to express the contract without naming `Session`/`SessionEvent` (from `dsh-session`) and `ContentBlock` (from `dsh-llm`).
+The capability-seams RFC states the interface package "depends only on cordis" (true of `dsh-bash`, whose vocabulary is self-contained). Compaction **cannot** honor that: its verbs act on an agent-owned `Session` (`compactRegion(start, end, agent)`) and its output uses the content vocabulary (`CompactionResult.summary: ContentBlock[]`). There is no way to express the contract without naming `Session`/`SessionEvent` (from `dsh-session`) and `ContentBlock` (from `dsh-llm`).
 
 This is not a coupling smell — it is the contract's domain. The "only cordis" guidance was always shorthand for "the interface depends only on what the contract genuinely names, and never on an implementation." `dsh-session` and `dsh-llm` are themselves interface/vocabulary packages, not implementations; `dsh-compact` still imports no backend. The seam's real invariant — *consumers and implementations evolve independently behind an abstract service* — holds intact.
 
@@ -30,7 +30,7 @@ This is not a coupling smell — it is the contract's domain. The "only cordis"
 
 An earlier draft put the full algorithm (the retention walk, token-summing, text extraction) as concrete methods on the interface. That recouples the contract to one strategy: a backend that wants a different retention policy or event sequence would have to fight inherited concrete code. Making both core methods abstract puts every *how* decision in the backend and keeps the interface a statement of *what*. Token measurement is not a compaction hook at all; the singleton service lets multiple consumers share one per-session replay fold.
 
-`compactIfNeeded(agent, fullSystemPrompt, sessionPrefix, signal)` takes required pressure inputs and cancellation. The session comes from the agent. `compactRegion(session, start, end, agent, signal?)` keeps an optional signal for manual callers and requires `session === agent.session`; implementations reject mismatch before model resolution, lock acquisition, summarization, or log mutation. The pre-step integration resolves a provisional model from the latest logged request header, then `AgentOptions.model`; a model-less router-only first step skips pressure because `agent/request` can route later. The default summarizer resolves its model from explicit config, the latest logged routed model, then agent options.
+`compactIfNeeded(agent, fullSystemPrompt, sessionPrefix, signal)` takes required pressure inputs and cancellation. `compactRegion(start, end, agent, signal?)` uses `agent.session` as its single session identity and keeps an optional signal for manual callers. The pre-step integration resolves a provisional provider/model pair from the latest logged request header, then `AgentOptions`; a model-less router-only first step skips pressure because `agent/request` can route later. The default summarizer resolves its target from explicit config, the latest logged routed target, then agent options.
 
 ### Auto-compaction runs on `agent/pre-step`, a dedicated surface-mutation seam
 

docs/rfc/implemented/feature/2026-06-21-subagent-capability-seam.md

@@ -10,7 +10,7 @@ The harness has a long-deferred seam for **subagents** — an agent delegating w
 
 The distinctive requirement — the one that shapes the whole design — is that **multiple subagent implementations must coexist at runtime**. A parent may want a cheap in-process child for a scoped subtask AND an isolated out-of-process child (over ACP) in the same session. The transports we foresee:
 
-- **in-process** — a child `ReactLoopAgent` on the same `Context` (the cheapest, and nearly free given the existing agent factory);
+- **in-process** — a child concrete `Agent` on the same `Context` (the cheapest, and nearly free given the existing agent factory);
 - **ACP** — act as an ACP *client* driving another agent process (which can be another instance of ourselves);
 - later: **A2A**, the **Codex app-server**, and the **Claude Code Agent SDK** — each the same out-of-process "start a child, prompt it, stream updates, cancel" shape as the ACP backend.
 

docs/rfc/implemented/feature/2026-06-25-ask-user-question.md

@@ -22,7 +22,7 @@ Providers return `{ answers: [{ id, selected, custom? }] }`. `selected` is alway
 
 `dsh-stdio-demo`'s in-package readline module renders each question, shows each option's `description` on the next line, supports comma/space-separated numeric choices for `multi_select`, accepts free-form custom answers, and rejects pending questions on abort, provider disposal, or stdin EOF. A batched request is asked in order and resolved as one answer object. The stdio provider serializes simultaneous requests with an internal queue so only one prompt owns stdin at a time.
 
-`dsh-acp` provides the same seam for ACP sessions. It routes an ask request from the calling `Agent` through the bridge's `agent→sessionId` reverse map and calls ACP `unstable_createElicitation` with a session-scoped form for each question. Single-select options become a `choice` string enum; `multi_select` options become a `choice` array enum; optionless questions use a required `custom` text field. If the client returns both `choice` and non-empty `custom`, the custom answer wins. ACP `decline`/`cancel`, a missing answer, a missing session, and a client without elicitation support all become structured `UserInteractionError`s.
+`dsh-acp` provides the same seam for ACP sessions. It resolves the calling `Agent` through `ownedRecord`, requiring the forward session-map record at `agent.session.id` to own that exact agent object, and calls ACP `unstable_createElicitation` with a session-scoped form for each question. Single-select options become a `choice` string enum; `multi_select` options become a `choice` array enum; optionless questions use a required `custom` text field. If the client returns both `choice` and non-empty `custom`, the custom answer wins. ACP `decline`/`cancel`, a missing answer, a missing session, and a client without elicitation support all become structured `UserInteractionError`s.
 
 The ACP mapping deliberately uses elicitation, not `session/request_permission`. `request_permission` is still reserved for the separate permission gate: it is a yes/no-or-policy authorization protocol around tool execution. `ask_user_question` is a general information-gathering tool with optional free-form answers, so ACP form elicitation is the closer protocol fit. The bridge's session routing is shared with the future permission gate, but the user intent is different.
 

docs/rfc/implemented/feature/2026-07-06-approval-seam.md

@@ -25,7 +25,7 @@ One `cordis.yml` entry mounts the seam. Not loading it is the fail-closed opt-ou
 
 The entry alone provides mechanism, not a channel: with no answerer composed, every ask resolves `unavailable` and the asking tool call denies — fail-closed needs no configuration. Composing the ACP app (`@deepseek-ai/dsh-acp-demo`, as in [the acp-agent example's default tree](../../../../examples/acp-agent/README.md)) completes the loop: its bridge registers an answerer that prompts the owning editor session via `session/request_permission`, so a hook's `ask` or an escalation request surfaces as a one-shot Allow/Reject prompt attached to the already-streamed tool call. `policy: never` is the unattended stance — every ask auto-rejects deterministically, stated in the system prompt, no human in the loop. `policy` is validated against the closed list at plugin load; anything else throws.
 
-What a composed deployment observes: `allowed-once` lets exactly that call proceed; rejection, dismissal, and channel absence deny with three distinct reasons the model can tell apart; every ask lands a durable `approval/asked`/`approval/decided` pair on the asking agent's session log; nothing about a grant persists past the call that asked.
+What a composed deployment observes: `allowed-once` lets exactly that call proceed; rejection, dismissal, and channel absence deny with three distinct reasons the model can tell apart; a successful in-turn request lands a durable `approval/asked`/`approval/decided` pair on the asking agent's session log; nothing about a grant persists past the call that asked. An idle request or audit append failure rejects instead of returning an unaudited decision.
 
 One ask under this composition, verbatim from the sandbox example's recorded `escalation-approved` scenario — the model requests a sandbox escalation, the gate asks, the bridge prompts the owning editor, the user clicks Allow once:
 
@@ -49,45 +49,44 @@ The `escalation-rejected` twin ends in `{"outcome": "rejected"}` instead: nothin
 
 #### The seam: mechanism and policy split
 
-After validation and an `approval/asked` append, `request()` resolves to `allowed-once`, `rejected`, `cancelled`, or `unavailable`. The service borrows the readonly request, runs the answerer waterfall, races cancellation, and normalizes thrown or invalid answers to `unavailable`. It then appends the matching `approval/decided`, paired by `ApprovalRequestId`.
+After validation and a successful `approval/asked` append, the service resolves the `approval/request` waterfall to `allowed-once`, `rejected`, `cancelled`, or `unavailable`. It borrows the readonly request identity and signal, treats abort as `cancelled`, contains answerer failures and invalid returns as `unavailable`, discards late answers, and appends the paired `approval/decided` event. Pre-commit audit failures reject; post-append observer failures cannot undo an authoritative event. `allowed-once` authorizes only the asked action, and `request()` rejects outside an open turn so the audit pair remains inside the durable commit boundary.
 
-Both audit events must be inside an open turn; acceptance or a pre-commit append failure rejects the request. Post-commit observers are contained by the session. `allowed-once` grants only the requested action, and the service retains no grant state.
+Answerers are `approval/request` waterfall listeners. Zero listeners fall through to `unavailable`; a recognizing listener occupies the first-wins decision slot, while an unrecognized agent must delegate with `next()`. Listeners dispose with their fibers, so an unloaded channel fails closed. Because sibling registration order is not deterministic, a deployment composes one terminal answerer and reserves `prepend` for decide-or-delegate gates.
 
-Answerers are `approval/request` waterfall listeners. A listener returns an outcome for an agent it owns and calls `next()` otherwise. With no answerer, the default is `unavailable`; unloading a UI therefore fails closed without leaving a channel. Because sibling registration order is not deterministic, a deployment composes one terminal answerer and uses `prepend` only for decide-or-delegate gates.
-
-`ApprovalRequest` carries the agent, tool name, optional `callId`, reason, and signal. The agent routes both the prompt and audit events. The request uses `dsh-llm`'s `CallId` without importing `dsh-tools`, avoiding a package cycle. Tool arguments are omitted because UI answerers attach to the already-rendered call.
+`ApprovalRequest` carries the asking `agent`, `toolName`, optional exact `callId`, human-readable `reason`, and optional `signal`. It uses the `CallId` brand without importing `dsh-tools`, which depends on this seam. Tool arguments stay on the already-streamed call that a UI references by `callId`.
 
 #### Ask routing in dsh-tools
 
-`ToolRegistry.execute()` sends `ask` through the approval seam before the deny path. Only `allowed-once` proceeds; rejection, cancellation, and an unavailable channel produce distinct model-visible reasons. The registry looks up the optional service per call, so an absent or unloaded service fails closed without gating the registry fiber. Agent-less execution also fails closed because it cannot be routed or audited.
+`ToolRegistry.execute()` resolves `ask` before dispatch: `allowed-once` proceeds, while rejection, cancellation, and channel absence produce distinct deny reasons. Opportunistic `ctx.get('approval')` consumption lets an absent or unmounted service fail closed without gating the registry fiber. Agent-less execution also fails closed because it has neither an audit session nor a UI owner.
 
 #### The per-session policy tier
 
-The seam owns the session policy `'ask' | 'never'`, following the switching contract in the [sandbox RFC](2026-07-06-sandbox.md). The effective session or config policy is applied before answerers: `'never'` rejects inside `request()`, while `'ask'` dispatches and falls through to `unavailable` when unanswered. The prompt states only deterministic `'never'`; the narrator reports switches, and every request still receives its audit pair.
+The seam also owns the session-scoped `'ask' | 'never'` policy described by [the sandbox RFC](2026-07-06-sandbox.md). Effective policy is folded from logged switches over the deployment default. `'never'` resolves to `rejected` inside `request()` before any answerer can run; `'ask'` dispatches and otherwise falls through to `unavailable`. The prompt states only deterministic `'never'`, switch narration is coalesced, and every request still records the audit pair.
 
 #### The ACP answerer
 
-The ACP bridge finds the owning session, sends `session/request_permission` for the `callId`, and maps one-shot allow, reject, and cancel responses to the seam vocabulary. Unknown selections never grant. Foreign agents and requests without a `callId` delegate via `next()`; RPC failure becomes `unavailable`. The bridge answers requests but does not decide which calls require approval.
+The ACP bridge answers only for an exact agent object owned by its forward session map. It attaches `session/request_permission` to the existing `callId`, advertises one-shot allow/reject options, maps cancellation separately, and never grants an unknown option. Foreign or call-less requests delegate; a failed client RPC becomes `unavailable`. Hooks and `tools/pre-execute` decide whether a call asks at all.
 
-The answerer routes through the bridge's reverse-map ownership seam described by [the ACP support RFC](../../implemented/feature/2026-06-14-acp-agent-client-protocol.md), implementing the per-session permission ownership required by [the multi-session RFC](../../implemented/feature/2026-06-14-acp-multi-session.md).
+The answerer routes through the bridge's exact-agent ownership check described by [the ACP support RFC](../../implemented/feature/2026-06-14-acp-agent-client-protocol.md), implementing the per-session permission ownership required by [the multi-session RFC](../../implemented/feature/2026-06-14-acp-multi-session.md).
 
 #### Audit, and what the model sees
 
-`approval/asked` and `approval/decided` are durable log-only events. The model sees only the asker's logged `tool/result`. Every accepted request appends one matching decision, including cancellation and contained answerer failures.
+`approval/asked` and `approval/decided` are durable log-only events; the model sees only the ordinary tool result derived from the outcome. Successful completion commits one `decided` per `asked`, including cancellation and contained answerer failure. Idle requests append neither event; a pre-commit failure rejects, while failure of the second append can leave an already-committed `asked` unmatched.
 
 #### Entities and dependencies
 
-`dsh-user-approval` owns the fixed dispatch-and-audit mechanism; `dsh-tools` asks and `dsh-acp` answers. Replaceable answerers remain listeners in their channel-owning plugins, so a three-package capability split would add an empty implementation layer. Sandbox executors remain transport-only, and static capability grants remain separate from interactive approval.
+`dsh-user-approval` depends on Cordis plus the session, agent, and branded-call contracts; `dsh-tools` and `dsh-acp` consume it. The sandbox executor stays independent because `dsh-tool-bash` owns escalation requests. The fixed dispatch-and-audit service remains one package; replaceable answerers live with their channel owners. Static capability grants and `subagent-acp` child-side permission answers remain separate concerns.
 
 ### Testing
 
-- **Unit/integration:** cover first-wins delegation, fail-closed defaults, malformed and throwing answerers, cancellation races and late-answer discard, audit pairing despite observer failures, unbypassable `'never'`, distinct tool-denial reasons, and ACP per-session routing/outcome mapping.
-- **Snapshot:** script permission answers through both sandbox escalation branches and pin the `'never'` prompt plus policy-switch notice. Hook-produced asks without a composed answerer remain covered as fail-closed denial.
+Unit tests pin outcomes, first-wins delegation, containment, cancellation, scoped routing, audit pairing, the unbypassable `'never'` policy, tool deny reasons, and ACP ownership/outcome mapping through a real scripted bridge.
+
+Snapshots record allowed and rejected sandbox escalation through `session/request_permission`, plus the `'never'` prompt and policy-switch notice. Unscripted permission prompts cancel and fail closed.
 
 ## Deferred
 
 - **`allow_always` grant storage** — honoring a persistent grant means designing storage, scope identity (call? path? prefix? session? time window?), and revocation; until designed, only the one-shot options are advertised ([the sandbox RFC](2026-07-06-sandbox.md) § Escalation records the open scope question).
-- **A recorded hook-produced ask with a composed answerer** — escalation records the human-prompt wire, while the current hook fixture pins the no-service denial; their combined producer/answerer path remains unit-covered.
+- **A recorded hook-driven `ask` through a composed answerer** — the human-prompt wire is recorded through the sandbox example's escalation branches. The hook matrix's `hook-cc-pretool-ask` pins the no-ApprovalService fallback denial, while the hook-producer-plus-answerer composition remains on the unit tier.
 - **Routing a child agent's approvals to the parent session** — `subagent-acp`'s child auto-answers its own `permission` requests; surfacing them to the parent's editor is its own design.
 
 ## Alternatives considered
@@ -101,16 +100,18 @@ The answerer routes through the bridge's reverse-map ownership seam described by
 
 ## Consequences
 
-- Only `allowed-once` dispatches an asked-about action; absent, rejected, cancelled, or failed answer paths deny.
-- Session ownership routes prompts, policy, and audit events without crossing editor sessions.
-- Accepted requests append one durable audit pair; the model sees only the resulting tool result.
-- A deployment without the service emits no approval prompt or audit events and denies every `ask` at the tool boundary.
+The implemented contract is pinned by the suites in Testing:
+
+- `allowed-once` dispatches one action; every other outcome denies with a distinct reason, and `'never'` rejects before prompting.
+- Missing, foreign, agent-less, throwing, invalid, and disconnected answer paths fail closed.
+- Successful requests route by exact agent ownership and append one replayable, model-invisible audit pair; idle and pre-commit failures reject.
+- ACP ownership keeps prompts inside their session, while a deployment without the service emits no prompt or audit events.
 
 Costs and accepted limits:
 
 - **Two decide-eager answerers race for the slot.** Sibling-plugin listener order is not deterministic, so the seam cannot referee competing terminal answerers — mitigated by convention (one terminal answerer per deployment; `prepend` only for decide-or-delegate gates) rather than a priority mechanism the event bus does not have.
 - **Production exercise rests on one composition.** `ask` has two producer families — the hook bridges through `tools/pre-execute`, and sandbox escalation through its own gate — with the wire recorded in the sandbox example's snapshot suite, so the seam's real-world coverage is that one composition until more deployments compose it.
-- **Ownership keys on `Agent` object identity.** The answerer resolves sessions through the bridge's existing WeakMap; every current path hands the same object through the loop and the seams, but a future boundary that clones or proxies agents would make the bridge delegate and fail closed — safe, but silently UI-less — and would need session-id matching instead.
+- **Ownership keys on `Agent` object identity.** The answerer resolves the forward session-map record at `agent.session.id`, then requires that record to own the exact agent object; every current path hands the same object through the loop and the seams, but a future boundary that clones or proxies agents would make the bridge delegate and fail closed — safe, but silently UI-less — and would need a different ownership contract.
 
 ## FAQ
 
@@ -118,10 +119,10 @@ Costs and accepted limits:
 - **Can a grant persist — "always allow this"?** No. `allowed-once` authorizes the single asked-about action and the service stores nothing between requests; `allow_always` is deliberately not advertised until grant storage is designed (§ Deferred).
 - **What does the model see of an approval?** Only the tool result the asker derives from the outcome — the audit pair never enters the transcript. The three non-grant reasons are distinct, so the model can tell a human "no" from a dismissed prompt from a missing channel.
 - **Who decides whether a call asks in the first place?** Policy producers: a hook returning `permissionDecision: ask`, any `tools/pre-execute` listener, or the sandbox escalation gate. The seam and the bridge only route and answer; neither injects its own judgment about what deserves a prompt.
-- **What happens when the user dismisses the prompt, or the turn aborts mid-ask?** Dismissal maps to `cancelled` with its own deny text. An already-aborted signal settles `cancelled` without dispatching; an abort during the ask discards the late answer — one audit pair either way, never two.
+- **What happens when the user dismisses the prompt, or the turn aborts mid-ask?** Dismissal maps to `cancelled` with its own deny text. An already-aborted signal settles `cancelled` without dispatching; an abort during the ask discards the late answer. When both audit appends commit, either path records one pair, never two.
 - **What if the client answers with an option the harness never offered?** Any selection other than the offered `allow_once` maps to `rejected` — an unknown optionId from a non-conforming client can never grant.
 - **How do subagents' approvals route?** An agent no answerer owns delegates through the whole waterfall and fails closed — in-process subagents are deliberately unanswerable. `subagent-acp`'s child-side auto-answer is separate; routing a child's asks to the parent's editor is deferred (§ Deferred).
-- **What does `policy: 'never'` actually change at runtime?** The service resolves every ask for that session to `rejected` before dispatching any answerer (in-service, so no registration order can bypass it); the system prompt states the policy; switches are narrated at boundaries; the audit pair still lands for every auto-rejection.
+- **What does `policy: 'never'` actually change at runtime?** The service resolves every ask for that session to `rejected` before dispatching any answerer (in-service, so no registration order can bypass it); the system prompt states the policy; switches are narrated at boundaries; each successful auto-rejection records the audit pair.
 - **What happens across a hot reload, or when the UI plugin unloads mid-session?** Answerers dispose with their owning fiber, so the next ask degrades to `unavailable` instead of hanging on a dead channel; remounting re-registers the answerer with no catch-up state.
 - **Where does the user see what they are approving?** On the tool call itself: the prompt attaches to the already-streamed call via `callId` — arguments included — and adds the asker's human-readable `reason`; the request carries no argument copy of its own.
 
@@ -132,5 +133,5 @@ In-repo precedents this design copies or contrasts with:
 - The `fs/write-intent` gate (`packages/fs/fs/`) — the documented single-occupancy decision-slot waterfall semantics (first answer wins, delegate via `next()`) the answerer contract reuses.
 - `hook/invoked`/`hook/result` — the log-only audit-pair precedent `approval/asked`/`approval/decided` follows; [the hook-bridges RFC](2026-06-30-hook-bridges.md) ships `permissionDecision: ask`, the first producer.
 - [The interception-seams RFC](2026-06-30-interception-seams.md) — the `tools/pre-execute` `allow`/`deny`/`ask` vocabulary whose `ask` this seam services.
-- [The ACP support RFC](../../implemented/feature/2026-06-14-acp-agent-client-protocol.md) — the `WeakMap<Agent, sessionId>` ownership seam the answerer routes through; [the multi-session RFC](../../implemented/feature/2026-06-14-acp-multi-session.md) — the per-session permission-ownership blocker this implements.
+- [The ACP support RFC](../../implemented/feature/2026-06-14-acp-agent-client-protocol.md) — the exact-agent ownership check against the forward session map that the answerer routes through; [the multi-session RFC](../../implemented/feature/2026-06-14-acp-multi-session.md) — the per-session permission-ownership blocker this implements.
 - The opportunistic `ctx.get()` consumption pattern (`tool-bash`'s owner-token lookup, the loop's persistence probe) — how `dsh-tools` consumes the seam without gating its fiber on it.

docs/rfc/implemented/feature/2026-07-08-repeat-tool-guard.md

@@ -12,11 +12,10 @@ The harness already has every seam the pi extension uses, and better ones: [the
 
 The guard is a loop-hygiene plugin, not a model-facing tool. It counts consecutive calls to the same tool with identical canonical arguments and injects advisory reminders at configured thresholds. It never delays, blocks, or rewrites a call; the model decides whether to retry differently or finish.
 
-The plugin is `@deepseek-ai/dsh-repeat-tool-guard` at `packages/guard/repeat-tool-guard/`, opening the `guard/` group for loop-hygiene plugins (single-package groups have precedent: [the todo-write RFC](2026-06-29-todo-write-tool.md) shipped `todo/tool-todo`). It registers three listeners and holds all state in plugin-local maps keyed by `AgentId` — the tool registry is a context-level singleton whose waterfalls interleave every agent's calls (subagents run on the same context), so per-agent keying is correctness, not polish.
+The plugin is `@deepseek-ai/dsh-repeat-tool-guard` at `packages/guard/repeat-tool-guard/`, opening the `guard/` group for loop-hygiene plugins (single-package groups have precedent: [the todo-write RFC](2026-06-29-todo-write-tool.md) shipped `todo/tool-todo`). It registers two listeners and holds state in a `WeakMap` keyed by the live `Agent` object — the tool registry is a context-level singleton whose waterfalls interleave every agent's calls (subagents run on the same context), so per-agent keying is correctness, not polish; weak object keys also make a disposal-only cleanup listener unnecessary.
 
 - **`tools/post-execute` (waterfall)** — the one detection point. The listener receives `(exec, result)` together, so counting and reminder delivery need no cross-event pending map (the pi extension needs one only because its `tool_call`/`tool_result` hooks are separate events). It always delegates via `next()` and, when a threshold is hit, prepends a reminder to the downstream decision's `additionalContexts` — the observe-and-enrich posture [the hooks bridges](2026-06-30-hook-bridges.md) already use, honoring the waterfall contract. Counting happens here rather than in `tools/pre-execute` because post-execute also runs for denied calls (`ToolRegistry.execute` routes a deny through the same pipeline), and a model hammering a denied call is exactly the loop worth breaking.
 - **`agent/prompt-submit` (waterfall)** — pure reset hook: delegate via `next()`, clear the submitting agent's chain. A user interjection changes the context; repetition across it is not a loop.
-- **`agent/status` (emit)** — on `disposed`, drop the agent's state, bounding the maps over harness lifetime.
 
 ### Detection semantics
 
@@ -25,7 +24,7 @@ The chain key is `(tool name, canonical arguments)`; a call identical to the pre
 Two deliberate rules, both documented in [the package README](../../../../packages/guard/repeat-tool-guard/README.md) because they are behavior a reader would otherwise guess at:
 
 - **Untracked calls are transparent to the chain.** A call excluded by `include`/`exclude` neither increments nor resets the counter, so `grep X → todo_write → grep X` still counts as two consecutive `grep X` when `todo_write` is excluded. This is what makes exclusion useful — bookkeeping tools interleaved into a loop must not launder it — and it is the pi extension's (undocumented) semantics, kept on purpose and written down.
-- **Calls without an agent are ignored.** A direct `ctx.tools.execute()` caller (tests, non-loop consumers) has no model to remind and no `AgentId` to key on.
+- **Calls without an agent are ignored.** A direct `ctx.tools.execute()` caller (tests, non-loop consumers) has no model to remind and no live agent object to key on.
 
 ### Reminder delivery
 

docs/rfc/implemented/simplification/2026-06-20-remove-agent-boundary-mirror-events.md

@@ -2,9 +2,18 @@
 
 Status: implemented
 
+<!-- Shipped in AMENDED, narrowed form: the four turn/step BOUNDARY mirrors are
+     removed; `agent/steering` and `agent/stream-chunk` were RETAINED here (they
+     are not durable-boundary mirrors — see "Scope: what is and isn't removed").
+     The original proposal bundled `agent/steering` into the removal; keeping it
+     out kept this RFC's scope to boundaries. Each retained event was later
+     removed by its own decision — see
+     [Stop mirroring the token stream as an agent event](2026-07-02-remove-stream-chunk-mirror.md)
+     and [Remove the `agent/steering` mirror emit](2026-07-04-remove-agent-steering-mirror.md). -->
+
 ## Problem
 
-The loop exposed durable turn and step boundaries through both the replayable `SessionEvent` log and live `agent/*` mirrors. Consumers had to choose between two sources for the same fact and reconcile their timing. ACP and persistence already used the log; the stdio UI was the only remaining mirror consumer and already rendered tool calls and results from `session/event`.
+The loop records the canonical transcript in `SessionEvent` and also emitted a parallel set of live `agent/*` boundary mirror events: `agent/turn-start`, `agent/turn-end`, `agent/step-start`, and `agent/step-end`. The mirrors made consumers choose between two sources of truth for the SAME durable fact. ACP already chose the session log for the editor-facing transcript because it is the one durable, replayable record; consuming a live mirror would require reconciling its timing with the boundary already stored in that log. The stdio UI was the only production consumer that still rendered turn boundaries from the mirror events; it already rendered tool calls and results from `session/event`.
 
 This duplication is not free. Every lifecycle change had to update the session event, the mirror event, docs, invariants, tests, and snapshot expectations. The duplicate boundary events also made failure ordering subtle: a turn can be durably closed before a live `agent/turn-end` listener runs, so a post-boundary listener failure has no valid in-log position left and must be reported out of band.
 
@@ -12,19 +21,25 @@ This duplication is not free. Every lifecycle change had to update the session e
 
 Make `session/event` the single live boundary/transcript stream. Consumers that render turns, tool calls, tool results, assistant messages, and durable boundaries subscribe to `session/event` and derive their UI from the same event vocabulary persistence uses.
 
-Remove `agent/turn-start`, `agent/turn-end`, `agent/step-start`, and `agent/step-end`. Boundary consumers subscribe to `session/event`. A UI that needs an agent label maintains a session-to-agent map from `agent/created` and `agent/disposed`, because the durable `turn/start` carries the turn number but not the agent id.
+The four durable-boundary mirrors — `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end` — are removed from the agent event taxonomy. A UI that wants the agent handle at a boundary retains the live target object from `agent/created`/`agent/disposed` and compares its session directly; `dsh-ui-stdio` uses this to label the app-owned agent's `[main turn N]` header while other sessions render their durable id. The canonical record remains the event-sourced session log.
 
-The step mirrors had no consumers and were removed first by the [event-domain-semantics RFC](../architecture/2026-06-30-event-domain-semantics.md). That decision retained the turn mirrors for the stdio UI; this RFC removes them after migrating that test REPL to `session/event` and the id map.
+The step mirrors (which had no consumer at all) were removed first, in [the event-domain-semantics RFC](../architecture/2026-06-30-event-domain-semantics.md); that RFC KEPT the turn mirrors on the stated justification that the stdio UI needed the `Agent` handle at the turn boundary. This RFC finishes the job: `dsh-ui-stdio` is a disposable test REPL whose rendering can change freely, so "ui-stdio needs it" is not a reason to keep a mirror — it reads `session/event` and retains only its live target object.
 
 ## Scope: what is and isn't removed
 
-This decision covers only durable turn and step boundaries. `agent/steering` mirrored a control record and `agent/stream-chunk` mirrored the token stream, so each was handled separately: [steering](2026-07-04-remove-agent-steering-mirror.md) and [stream chunks](2026-07-02-remove-stream-chunk-mirror.md). `agent/created`, `agent/disposed`, `agent/status`, `agent/error`, and `agent/queued` remain live lifecycle or control events rather than transcript mirrors; queued input may be cancelled before any durable event exists.
+Removed (durable-boundary mirrors — the session log is authoritative for each): `agent/turn-start`, `agent/turn-end`, `agent/step-start`, `agent/step-end`.
+
+RETAINED — NOT durable-boundary mirrors, so out of scope for this decision:
+
+- `agent/steering` — not a boundary, so out of scope for THIS decision (the original proposal bundled it into the removal; that would have been scope creep here). It mirrors the durable `steering/message` control record rather than a boundary, and was removed by its own follow-up: [Remove the `agent/steering` mirror emit](2026-07-04-remove-agent-steering-mirror.md).
+- `agent/stream-chunk` — the live token stream. Out of scope for THIS decision (a mirror of the durable `assistant/chunk`, not a boundary), it was removed by its own follow-up: [Stop mirroring the token stream as an agent event](2026-07-02-remove-stream-chunk-mirror.md).
+- `agent/created`, `agent/disposed`, `agent/status`, `agent/error`, `agent/queued` — lifecycle/control events that are not transcript data. `agent/queued` in particular is an inbox acknowledgement that fires before any durable event exists (cancelled queued work may never enter the log), so it is deliberately live-only.
 
 ## Alternatives considered
 
-- **Remove `agent/steering` in the same change** — rejected because it was a control-record mirror rather than a boundary mirror.
-- **Keep turn mirrors for the stdio UI** — rejected because the UI can render `session/event` and recover the agent label from its id map.
+- **Bundling `agent/steering` into the removal** — the original proposal's shape; narrowed out as scope creep: it mirrors the durable `steering/message` control record, not a boundary, and was removed by [its own later decision](2026-07-04-remove-agent-steering-mirror.md) (as was `agent/stream-chunk`, by [the stream-chunk-mirror RFC](2026-07-02-remove-stream-chunk-mirror.md)).
+- **Keeping the turn mirrors for the stdio UI** — [the event-domain-semantics RFC](../architecture/2026-06-30-event-domain-semantics.md)'s original stance; rejected here because `dsh-ui-stdio` is a disposable test REPL, not a load-bearing consumer, and it renders boundaries from `session/event` plus its live target object instead.
 
 ## Consequences
 
-A plugin can no longer observe turn/step boundaries from a convenient `Agent`-first event. It must either subscribe to `session/event` or maintain a session-to-agent association. That is an acceptable trade: boundary consumers should not depend on a second event feed that can drift from the durable log.
+A plugin can no longer observe turn/step boundaries from a convenient `Agent`-first event. It subscribes to `session/event` and, if it needs the live object, resolves the shared id through `ctx.agents` or retains the object it already owns. That is an acceptable trade: boundary consumers should not depend on a second event feed that can drift from the durable log.

docs/rfc/implemented/simplification/2026-06-20-unify-agent-and-session-id.md

@@ -0,0 +1,38 @@
+# RFC: Unify the agent id and the session id
+
+Status: implemented
+
+## Problem
+
+A live agent/session pair needs one identity for registry routing, event sourcing, and persistence. Giving the factory independent `agentId` and `sessionId` inputs would permit pairings no production path can use, while forcing every consumer to choose or translate between two names for the same lifecycle.
+
+ACP uses the same value for both identities. Stdio and hooks also operate on the session event stream and need the corresponding live agent directly; no production path reattaches one live agent object to several sessions or drives one session through several agent ids.
+
+The [agent-scope runtime](../../implemented/architecture/2026-07-12-agent-scope-runtime-design.md) uses one `AgentCreationTransaction` for create and resume, and agent/session entries share the same final-entry collision rule. A second identity would not represent separate liveness, rollback, or quiescence; it would only add API and translation state around the same transaction.
+
+Session identity likewise has one home in `Session.header.id`; `Session.id` is a derived accessor rather than independent state that needs duplicate validation.
+
+## Decision
+
+An agent's registry id equals its session id. `CreateAgentOptions` accepts one `sessionId` used for both final registry entries; resume registers the agent under `resumeSessionId`; in-process subagent creation uses the child session id; and `Session.id` derives from `header.id`. A remote ACP run has no local agent/session pair: it keeps one parent-minted lifecycle id while the child server's wire-local session id remains private to ACP calls. The existing creation transaction, final-entry collision checks, and exact-entry detach semantics remain; maps and fields whose sole job was translating between local ids are gone.
+
+The config-driven path keeps `agents[].id` as a stable configuration label, not a live routing identity. An ordinary fresh start mints the combined id `${label}-session-${randomUUID()}` so durable restarts do not collide. A coupled app may pre-mint and pass an exact `sessionId`: first use creates it, while an AgentLoop remount with an already-present persistence service resumes materialized history under that same identity. `resumeSessionId` instead requires an existing persisted identity. The two exact-id inputs are mutually exclusive. Stdio uses the resume-or-create form so its config-created agent and UI share one opaque identity across loop reloads instead of guessing from a prefix. Logs may use the stable label while all live and durable lookups use the one `SessionId`.
+
+`agent/created` and `agent/disposed` remain. They are paired publication lifecycle events, not identity aliases; any later consumer-free removal needs its own proposal after a fresh search.
+
+## Alternatives considered
+
+**Keep separate routing and log identities.** A stable configured label plus a fresh durable conversation is useful, but it does not require two live identities: the label can remain configuration/display metadata while the combined per-run `SessionId` owns routing and persistence. Keeping two ids would preserve translation maps and permit impossible pairings without adding lifecycle capability.
+
+## Verification
+
+- Agent create/resume and subagent creation carry one identity, and `Session` stores it in one place.
+- The creation transaction retains final-entry collision, exact-entry detach, rollback, and quiescence coverage without identity-specific lifecycle state.
+- ACP, stdio, hooks, bash ownership, persistence, and lineage use the shared `SessionId` directly. The ACP subagent backend mints its lifecycle id in the parent namespace because a child server's returned session id is only server-local; the ACP bridge verifies exact `Agent` ownership from the forward session map; and JSON-RPC forwards only lifecycle events whose service-snapshotted `local` flag is true, obtains the delegating parent from the scoped event carrier, and keeps no child identity or lineage cache.
+- The config-driven resume-or-create policy is explicit and covered across a durable restart.
+- A production listener search kept `agent/created`/`agent/disposed` and their publication semantics.
+- Typecheck, coverage, snapshots, doc-sync, module-graph verification, build, and hygiene pass.
+
+## Consequences
+
+This forecloses latent multi-session-actor and session-handoff designs and makes persisted client-chosen session identity the registry identity. If separate routing identity becomes a real requirement, it needs an explicit lifecycle design rather than an unconstrained caller-supplied pair.

docs/rfc/implemented/simplification/2026-07-02-remove-stream-chunk-mirror.md

@@ -42,4 +42,4 @@ Not touched:
 
 ## Consequences
 
-A plugin can no longer observe token deltas from an `Agent`-first event. It subscribes to `session/event` and filters `assistant/chunk` (the `Agent` handle, if needed, is recovered from a session-id→agent map built from `agent/created`/`agent/disposed`, exactly as boundary consumers already do). No production consumer needed the live `Agent` at chunk time; this is the same acceptable trade the boundary-mirror removal made.
+A plugin can no longer observe token deltas from an `Agent`-first event. It subscribes to `session/event`, filters `assistant/chunk`, and looks up the corresponding live handle directly with `ctx.agents.get(session.id)` when needed. No production consumer needed the live `Agent` at chunk time; this is the same acceptable trade the boundary-mirror removal made.

docs/rfc/implemented/testing/2026-06-11-property-based-testing.md

@@ -20,7 +20,7 @@ Adopt `fast-check` (a root devDependency) with one `tests/properties.spec.ts` pe
 ## Consequences
 
 - Generator quality is the value lever — the generators bias toward small index pools and short strings so collisions and interleavings are common.
-- **It already paid off:** the BlockAssembler stream found a real bug — a duplicate `block-end` at the same index overwrote an already-flushed block, so the streamed prefix disagreed with final `blocks()`. Fixed (first close wins, matching the existing straggler rule) with a dedicated regression test.
+- **It already paid off:** the BlockAssembler stream found a real bug — a duplicate `block-end` at the same index rewrote a completed block. Fixed (first close wins, matching the existing straggler rule) with a dedicated regression test.
 - A property flake from a timeout is a finding, not something to retry away. The loop properties are deterministic by construction (settle on `agent/status`), so a hang is a real defect.
 - Property tests supplement, not replace, the example tests that pin specific branches for the 100%-coverage gate.
 

docs/rfc/implemented/testing/2026-06-19-acp-snapshot-tests.md

@@ -28,7 +28,7 @@ Each scenario's `session.jsonl` is harvested from a real run. `assistant/chunk`
 
 ```
 { kind: 'chunks', chunks: StreamChunk[] }
-| { kind: 'throw', chunks: StreamChunk[], message: string, code: string, status?: number }
+| { kind: 'throw', chunks: StreamChunk[], message: string, code: string }
 | { kind: 'hang' }
 ```
 

docs/rfc/implemented/testing/2026-06-20-remove-redundant-snapshot-log-goldens.md

@@ -6,7 +6,7 @@ Status: implemented
 
 Model-driving ACP snapshot scenarios ship both `session.jsonl` and `session.golden.jsonl`. For normal recorded scenarios, `session.jsonl` is the replay fixture harvested from a real run, and the replay test normalizes the newly persisted log and compares it to `session.golden.jsonl`. In the current fixtures, the normalized recorded log and normalized golden are identical for the ordinary recorded scenarios.
 
-Authored override scenarios (`error-finish`, `cancel`) currently use `replay.override.json` to drive model behavior and keep `session.jsonl` as a minimal dummy fixture, while `session.golden.jsonl` holds the expected persisted log. The override file is a JSON array of `ReplayEntry` objects: `{ "kind": "chunks", "chunks": StreamChunk[] }`, `{ "kind": "throw", "chunks": StreamChunk[], "message": string, "code": string, "status"?: number }`, or `{ "kind": "hang" }`. That split is also unnecessary: when an override sidecar exists, `llm-replay` replaces the derived script and does not need `session.jsonl` for model chunks, so `session.jsonl` can still be the expected session-log artifact for the scenario.
+Authored override scenarios (`error-finish`, `cancel`) currently use `replay.override.json` to drive model behavior and keep `session.jsonl` as a minimal dummy fixture, while `session.golden.jsonl` holds the expected persisted log. The override file is a JSON array of `ReplayEntry` objects: `{ "kind": "chunks", "chunks": StreamChunk[] }`, `{ "kind": "throw", "chunks": StreamChunk[], "message": string, "code": string }`, or `{ "kind": "hang" }`. That split is also unnecessary: when an override sidecar exists, `llm-replay` replaces the derived script and does not need `session.jsonl` for model chunks, so `session.jsonl` can still be the expected session-log artifact for the scenario.
 
 ## Decision
 

docs/rfc/implemented/testing/2026-06-22-fork-snapshot-scenarios.md

@@ -17,7 +17,7 @@ Record two scenarios against the real API, both replayed keyless in the default
 
 ### Why a completed turn-1 is required
 
-The fork backend seeds the child with the parent's **balanced completed-turn prefix** ([`completedTurnPrefix`](../../../../packages/subagent/subagent-fork)). A parent that forks on its very first turn has no completed turn to inherit, so the seed is empty (≡ a fresh spawn, `seedLength` 0) — which would NOT exercise the slice. Both scenarios therefore use a two-prompt input: the first prompt completes a turn (establishing a codeword the child is later asked to recall), the second delegates the fork. The recalled codeword in the child's transcript is incidental to the model's behavior; the load-bearing artifact is the child fixture's recorded `seedLength`, which the replay slice consumes.
+The fork backend seeds the child with the parent's **balanced completed-turn prefix**. A parent that forks on its very first turn has no completed turn to inherit, so the seed is empty (≡ a fresh spawn, `seedLength` 0) — which would NOT exercise the slice. Both scenarios therefore use a two-prompt input: the first prompt completes a turn (establishing a codeword the child is later asked to recall), the second delegates the fork. The recalled codeword in the child's transcript is incidental to the model's behavior; the load-bearing artifact is the child fixture's recorded `seedLength`, which the replay slice consumes.
 
 ## Consequences
 

docs/rfc/implemented/testing/2026-07-04-hook-snapshot-matrix.md

@@ -29,6 +29,8 @@ Thirteen scenarios under `examples/acp-agent/tests/snapshots/`, naming `hook-<di
 
 Each hook command emits only FIXED LITERAL strings (no timestamps/pids/`$RANDOM`/cwd echoes); the snapshot normalizer scrubs the one volatile field a `hook/result` carries (`durationMs`). The `Stop` scenarios self-limit with a marker file (`.stop_fired`) so the force-continue does not loop — the `stop_hook_active` loop-guard is still a bridge `TODO`, so an unconditional Stop hook would force-continue every step.
 
+The `PostToolUse` block scenarios self-limit at the mechanism they prove. The Claude hook persists a workspace marker after its first rejection, so one recovery call is allowed; the Codex prompt makes one call and reports the injected result. Each golden pins one blocked call without repeated block/retry cycles.
+
 ### Three hook points are deliberately NOT snapshotted
 
 Discovered while building the matrix, and documented here because the omission is a decision, not an oversight:
@@ -41,7 +43,7 @@ The matrix therefore covers every hook point that has a DETERMINISTIC, OBSERVABL
 ## Consequences
 
 - Every bridge seam mapping with an observable transcript is now guarded at the full-transcript tier, in the real app, for both dialects — including the Codex bridge, which had no end-to-end coverage at all. Recorded goldens capture the model's real reaction to a denied/blocked/force-continued turn, which a hand-authored transcript could only guess at.
-- The block scenarios are keyless (no model turn); the rest replay keyless from recorded fixtures. `pnpm run test:snapshot:record` regenerates the recorded fixtures from the live API and self-skips without a key like every recorded scenario.
+- The `UserPromptSubmit` block scenarios are authored keylessly (no model turn); the rest replay keylessly from recorded fixtures. `pnpm run test:snapshot:record` regenerates the recorded fixtures from the live API and self-skips without a key like every recorded scenario.
 - The prove-red discipline holds: tampering a hook config's output (e.g. changing a deny reason) turns its scenario red on replay — the hook process runs FOR REAL during replay (only the model is replayed), so the golden guards the actual hook→seam→loop path, not a mock of it.
 - The `acp-agent` demo now loads a Codex bridge it will usually no-op (no `codex-hooks.json` in a typical project), which is the intended fail-soft behavior, not a cost.
 

docs/rfc/implemented/testing/2026-07-08-shared-acp-snapshot-package.md

@@ -6,17 +6,19 @@ Status: implemented
 
 The ACP snapshot tier ([snapshot RFC](2026-06-19-acp-snapshot-tests.md)) was built from three modules living inside one example's test directory: `snapshot-harness.ts` (boot the real bin subprocess, drive it over ACP JSON-RPC, harvest the persisted logs), `snapshot-normalize.ts` (the pure golden normalizers), and the ~150-line scenario body plus fixture guards in `acp.snapshot.ts` (record/replay modes, the stdout-golden and log compares, the pinned-header uniformity guard, the orphan/required-file/single-pin meta-tests).
 
-A second ACP example could only copy record, normalization, and harvest logic that must stay consistent. Code under `examples/` also sat outside the package coverage gate, and the original harness could only cancel permission requests. The shared package makes the machinery measured and lets scenarios script approval answers.
+A second ACP example wanting snapshot coverage — the sandbox/approval composition is the immediate consumer — could only copy those modules, forking exactly the logic that must not drift: record write-back, header scrubbing, child-session harvest ordering. The spawn/client glue was also triplicated across `acp.e2e.ts`, `hooks.e2e.ts`, and the harness. Location decided test rigor: the per-file 100% coverage gate measures `packages/*/*/src` only, so none of this machinery was measured — the same gap that had moved `dsh-llm-replay` out of `examples/` into [packages/support](../../../../packages/support/README.md). And the harness's ACP client hardcoded `requestPermission → cancelled`, so an approval round-trip — the headline behavior of the sandbox composition — could not be expressed at the snapshot tier at all.
 
 ## Decision
 
 The machinery lives in [`packages/support/acp-snapshot`](../../../../packages/support/acp-snapshot/README.md) (`@deepseek-ai/dsh-acp-snapshot`); an example's `*.snapshot.ts` is its scenario table, its agent paths, and one factory call, over its own `snapshots/` fixtures and `cordis.snapshot.yml` overlay ([single-source replay config](2026-07-04-single-source-acp-replay-config.md)). Reading `DSH_SNAPSHOT` stays at that edge — the library takes a resolved `mode`.
 
-**`src/harness.ts`** provides `runScenario` and its script/result types, parameterized by the agent's bin and config paths. Permission answers form a FIFO queue keyed by stable option kind rather than random option id. Missing answers cancel the request; an unavailable kind cancels the agent request and fails the scenario.
+**`src/launcher.ts`** — `launchAcpTestAgent` owns the common unbuilt-process boundary: absolute tsx loader resolution, `TSX_TSCONFIG_PATH`, isolated harness homes, stdio wiring, a raw-byte stdout tee, stderr and update capture, fail-closed permission fallback, update waiters, and graceful or signalled shutdown. Snapshot scenarios and ordinary e2e suites supply the same `AgentUnderTest` (`binScript`, `configPath`, `tsconfigPath`); a test that plays a user supplies only its permission handler. The ACP and hook e2e suites plus the sandbox/approval e2e suite use this launcher instead of rebuilding the SDK client boundary.
+
+**`src/harness.ts`** — `runScenario` and the input-script/result types layer deterministic steps, temp workspaces, snapshot environment, and persisted-log harvest over the launcher. Its `session/request_permission` handler consumes an optional `InputScript.permissionAnswers` FIFO queue, each entry selecting by option **kind** (ids are agent-issued randoms a committed script cannot know; kinds are the ACP-stable vocabulary, mapped to the offered `optionId` at answer time); an absent or exhausted queue answers `cancelled`, and a kind the request never offered rejects the run — the agent itself is answered `cancelled`, so the scenario bug fails the harness rather than being absorbed as an agent-side denial. This is what lets an approval suite drive allow/reject round-trips deterministically from `input.json`.
 
 **`src/normalize.ts`** — the pure normalizers, hook-free by policy: when a future event carries a new volatile field (an approval duration, say), the shared normalizer learns it in the same change, keeping one home for what "normalized" means rather than per-suite scrub extensions.
 
-**`src/suite.ts`** — the `Scenario` type and `defineAcpSnapshotSuite(options)`, registering the per-scenario compares, record/refresh fixture write-back, the header pin with its live uniformity guard, and the fixture guard block (no orphan scenario dirs, required files present, exactly one pin per class, every JSONL a `scrubSystemPrompts` fixed point, non-pinning fixtures also `scrubRequestHeaders` fixed points). The pinned-header contract ([pinned-header RFC](2026-07-06-pin-request-header-content-in-one-scenario.md)) is per-suite: each header class flags exactly one `pinsHeader` scenario, whose `system-prompt.golden.md` and JSONL tool list split the composed header into reviewable artifacts; the uniformity guard compares both against every live header in that class. A pinning scenario declares any legitimate changed-header count, and its Markdown artifact records every full changed prompt. The pure helpers (`childFixturePaths`, `fixtureContext`, `normalizedHeaders`, `normalizedSystemPrompts`, `formatSystemPromptSnapshot`, `headerChangeCount`) are exported from the module for direct unit coverage.
+**`src/suite.ts`** — the `Scenario` type and `defineAcpSnapshotSuite(options)`, registering the per-scenario compares, record/refresh fixture write-back, the header pin with its live uniformity guard, and the fixture guard block (no orphan scenario dirs, required files present, exactly one pin per class, every JSONL a `scrubSystemPrompts` fixed point, non-pinning fixtures also `scrubRequestHeaders` fixed points). A scenario directory's `session.jsonl` plus contiguous `session.<n>.jsonl` siblings are its ordered primary/child inventory, so the scenario table declares policy without duplicating a child count. The pinned-header contract ([pinned-header RFC](2026-07-06-pin-request-header-content-in-one-scenario.md)) is per-suite: each header class flags exactly one `pinsHeader` scenario, whose `system-prompt.golden.md` and JSONL tool list split the composed header into reviewable artifacts; the uniformity guard compares both against every live header in that class. A pinning scenario declares any legitimate changed-header count, and its Markdown artifact records every full changed prompt. The pure helpers (`sessionFixtureNames`, `fixtureContext`, `normalizedHeaders`, `normalizedSystemPrompts`, `formatSystemPromptSnapshot`, `headerChangeCount`) are exported from the module for direct unit coverage.
 
 ## Alternatives considered
 
@@ -29,8 +31,8 @@ The machinery lives in [`packages/support/acp-snapshot`](../../../../packages/su
 
 ## Testing
 
-Extraction preserved every existing ACP golden byte. The package's `src/` has per-file 100% coverage through a scripted ACP subprocess: harness tests cover every step operation, both expected-error branches, permission selection/fallback/impossible choice, environment forwarding, workspace seeding, and harvest ordering/noise/fallback; suite tests execute replay against committed synthetic fixtures and record against a temporary copy, plus the pure helpers. Two structurally unreachable guards retain reasoned coverage exclusions. The fake agent substitutes the `session/new` cwd into logs, including Darwin's `/var` realpath behavior, matching the real bin.
+Extraction parity was proven mechanically: after the move, `pnpm run test:snapshot` matched the base commit's result with zero byte changes under `examples/acp-agent/tests/snapshots/`. The package's `src/` holds per-file 100% statements/branches/functions/lines under the gating unit run, driven through the real launcher by a scripted fake ACP bin (`tests/fixtures/fake-acp-agent.ts`, behavior scripted per scenario via a `behavior.json` beside the fixture): `harness.spec.ts` directly covers launcher defaults, captures, update waiting, shutdown, and environment/config variants, then covers every scenario step op, both expect-error arms, the permission queue (selection, fallback, impossible-click), workspace seeding, and the harvest ordering/noise/fallback branches; `suite.spec.ts` runs the factory for real at collection time — a replay suite over committed synthetic fixtures and a record suite over a temp copy (write-back never touches the committed tree; `ACP_SNAPSHOT_SPEC_BOOTSTRAP=1` re-bootstraps it) — plus direct cases for the pure helpers. The fake bin substitutes the `session/new` cwd, not `process.cwd()`, into scripted logs, matching what the real bin's header carries (darwin realpaths `/var/folders/…` to `/private/var/folders/…`).
 
 ## Consequences
 
-A new example gets the whole snapshot tier from a scenario table plus fixtures — the sandbox branch merges master down and adds its own suite (own pin scenario, own overlay, fixtures via `test:snapshot:record`, approvals via `permissionAnswers`). The costs: `suite.ts` imports vitest, so the package is importable only inside a vitest run — a shape no other package has, stated in its README; each suite pins its own ~8 KB header fixture (a genuinely distinct composition deserves its own pin; an identical one would be caught by that suite's uniformity guard); and the e2e launcher duplication remains (`TODO(acp-test-harness)`) — the harness is the extraction target when that migration lands.
+A new example gets the whole snapshot tier from a scenario table plus fixtures, while an ordinary ACP e2e gets the same tested process/client boundary from one launcher call. The costs: `suite.ts` imports vitest, so the package entry is importable only inside a vitest run — a shape no other package has, stated in its README; and each suite pins its own ~8 KB header fixture (a genuinely distinct composition deserves its own pin; an identical one would be caught by that suite's uniformity guard).