From 9e575a2a2cc016c30aee0a9225c858269ea9e31a Mon Sep 17 00:00:00 2001
From: Tianyi Cui <53024+tianyicui@users.noreply.github.com>
Date: Thu, 2 Jul 2026 03:47:37 +0800
Subject: [PATCH] docs(events): fix stale turn-mirror references caught in
 review
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Codex review of the turn-mirror removal found current-state docs/comments that
still claimed the removed `agent/turn-start`/`agent/turn-end` events exist:

- docs/architecture.md: the loop diagram's turn-start line still said "emit
  agent/turn-start" (the turn-end line was already fixed).
- event-domain-semantics RFC: the `agent/*` domain description listed "the turn
  boundaries" among the transient emits.
- docs/core-data-structures/core.md: the agent/* taxonomy blurb listed
  "turn/step boundaries" as agent events.
- the proposed ACP RFC: the settle-signal rows named agent/turn-start /
  agent/turn-end; retargeted to the durable `turn/end` session event + the
  session/event owning-turn correlation.
- loop.ts outer-catch comment: said "closeTurn/failTurn are idempotent" — after
  the emit-param removal closeTurn is called exactly once (mutually exclusive
  normal/catch paths), so corrected to state that and to scope idempotency to
  closeStep (which is still guarded by stepOpen).

Regenerated the cordis catalog. No behavior change.
---
 docs/architecture.md                                |  2 +-
 docs/core-data-structures/core.md                   |  2 +-
 .../2026-06-30-event-domain-semantics.md            |  2 +-
 .../feature/2026-06-14-acp-agent-client-protocol.md |  4 ++--
 packages/core/agent-loop/src/loop.ts                | 13 ++++++++-----
 5 files changed, 13 insertions(+), 10 deletions(-)

diff --git a/docs/architecture.md b/docs/architecture.md
index 8f83625ab0..4e856305ec 100644
--- a/docs/architecture.md
+++ b/docs/architecture.md
@@ -134,7 +134,7 @@ forever:
   wait for queued messages (idle)
   emit agent/status(running)
   TURN (error-contained — a throwing plugin ends the turn, never the loop):
-    drain queued → 'turn/start' → session('user/message'…) → emit agent/turn-start
+    drain queued → 'turn/start' → session('user/message'…)   ⟵ durable turn boundary (no agent/* mirror)
     STEP loop:
       drain steering (late steering from previous step's listeners)
       assembly = ctx.systemPrompt.assemble()          ⟵ waterfall system-prompt/assemble
diff --git a/docs/core-data-structures/core.md b/docs/core-data-structures/core.md
index 34cf410944..7466b063eb 100644
--- a/docs/core-data-structures/core.md
+++ b/docs/core-data-structures/core.md
@@ -306,7 +306,7 @@ interface Agent {
 }
 ```
 
-`AgentStatus` is `'idle' | 'running' | 'disposed'`. `AgentId` is a branded string. `AgentOptions` (`model?`, `systemPrompt?`) is merge-extensible — plugins add creation options by declaration merging. The `agent/*` event taxonomy (lifecycle, turn/step boundaries, the serial `agent/pre-step` surface-mutation seam, and the `agent/request`/`agent/step-result`/`agent/turn-continuation` waterfalls) is in [architecture.md § Event taxonomy](../architecture.md#event-taxonomy).
+`AgentStatus` is `'idle' | 'running' | 'disposed'`. `AgentId` is a branded string. `AgentOptions` (`model?`, `systemPrompt?`) is merge-extensible — plugins add creation options by declaration merging. The `agent/*` event taxonomy (lifecycle emits, the serial `agent/pre-step` surface-mutation seam, and the `agent/request`/`agent/step-result`/`agent/turn-continuation` waterfalls) is in [architecture.md § Event taxonomy](../architecture.md#event-taxonomy); turn/step boundaries are durable `session/event` records, not `agent/*` emits.
 
 ## `ToolDefinition`
 
diff --git a/docs/rfc/implemented/architecture/2026-06-30-event-domain-semantics.md b/docs/rfc/implemented/architecture/2026-06-30-event-domain-semantics.md
index 5ca6f874b5..7ae254f8dc 100644
--- a/docs/rfc/implemented/architecture/2026-06-30-event-domain-semantics.md
+++ b/docs/rfc/implemented/architecture/2026-06-30-event-domain-semantics.md
@@ -19,7 +19,7 @@ This is the foundational change in a stack that adds a Hooks subsystem; it estab
 **Three domains, one job each, with a single boundary rule.**
 
 - **`session/*` — the durable, replayable FACT log.** Owns `SessionEventMap`; every entry is JSON-only (no live objects). One `session/event` emit per append, plus the `session/flush` parallel durability checkpoint. It is also the live transcript feed: a consumer that wants to render or react to what happened subscribes here, so live rendering and `session/load` replay share one path.
-- **`agent/*` — the LIVE runtime surface.** Always carries the live `Agent`. Two shapes: INTERCEPTION waterfalls (`agent/request`, `agent/step-result`, `agent/turn-continuation`) that mutate or veto, and TRANSIENT emits (`agent/status`, `agent/stream-chunk`, `agent/error`, `agent/created`/`agent/disposed`, `agent/queued`, `agent/steering`, and the turn boundaries) that notify with the `Agent` in hand.
+- **`agent/*` — the LIVE runtime surface.** Always carries the live `Agent`. Two shapes: INTERCEPTION waterfalls (`agent/request`, `agent/step-result`, `agent/turn-continuation`) that mutate or veto, and TRANSIENT emits (`agent/status`, `agent/stream-chunk`, `agent/error`, `agent/created`/`agent/disposed`, `agent/queued`, `agent/steering`) that notify with the `Agent` in hand. Turn and step BOUNDARIES are NOT here — they are durable session events read off `session/event`.
 - **`tools/*` — the tool registry + execution seam.**
 
 **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.
diff --git a/docs/rfc/proposed/feature/2026-06-14-acp-agent-client-protocol.md b/docs/rfc/proposed/feature/2026-06-14-acp-agent-client-protocol.md
index 675e295c2c..0aa5af4dc4 100644
--- a/docs/rfc/proposed/feature/2026-06-14-acp-agent-client-protocol.md
+++ b/docs/rfc/proposed/feature/2026-06-14-acp-agent-client-protocol.md
@@ -27,7 +27,7 @@ The mapping between ACP and existing harness seams — each row names the seam a
 | `session/new {cwd, mcpServers, additionalDirectories}` → `{sessionId}` | the `dsh-agent` create factory (see Dependency note + Plan) | the seam must accept `{ sessionId, meta }` so the ACP-generated `sessionId` becomes the live/persisted session id and the validated `cwd` is attached as the `SessionHeader` (today `AgentLoop.create(id)` hardcodes `${id}-session` and takes no metadata); reject a 2nd session (single-session MVP, see [ACP multi-session](2026-06-14-acp-multi-session.md)); `cwd` validated (require absolute) — any absolute cwd is honored: it becomes the session's `SessionHeader.cwd` and the default bash workdir (per-session cwd, see § Deferred → RESOLVED), so the server need not launch in the workspace; non-empty `mcpServers` and `additionalDirectories` are rejected for the MVP because silently ignoring requested servers/roots would desync the client's tool and filesystem-scope UI |
 | `session/load {sessionId, cwd, mcpServers, additionalDirectories}` | the `dsh-agent` resume factory ([session persistence](../../implemented/architecture/2026-06-14-session-persistence.md) + Dependency note) | load `{ meta, events }`, seed the session, re-derive history via `deriveMessages()`, replay prior turns to the client as `session/update` per the ACP load contract; `mcpServers` and `additionalDirectories` rejected as in `session/new` |
 | `session/prompt {prompt}` | `agent.send()` (idle) | text blocks → `TextBlock`; reject image/audio per advertised capabilities; one in-flight prompt per session |
-| resolve `session/prompt` → `{stopReason}` | `agent/turn-end` (extended, see Plan) | map the harness kebab `TurnEndReason` to the ACP snake_case `StopReason` wire enum: `completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`(cancel)→`cancelled`, plus `refusal`/`max_turn_requests` when applicable; honor the batch-into-one-turn and send-not-synchronously-running settle semantics |
+| resolve `session/prompt` → `{stopReason}` | the `turn/end` `session/event` (its `reason`) | map the harness kebab `TurnEndReason` to the ACP snake_case `StopReason` wire enum: `completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`(cancel)→`cancelled`, plus `refusal`/`max_turn_requests` when applicable; honor the batch-into-one-turn and send-not-synchronously-running settle semantics |
 | `session/update: agent_message_chunk` | `agent/stream-chunk` `text-delta` only | do NOT also emit on `block-end(TextBlock)` — it carries the fully-assembled block and would duplicate the streamed text |
 | `session/update: agent_thought_chunk` | `agent/stream-chunk` `reasoning-delta` | |
 | `session/update: tool_call` (pending→in_progress) | `session/event` `tool/call` | demux via a Session→sessionId map; `kind` inferred from the tool name |
@@ -46,7 +46,7 @@ Lifecycle and disposal: the connection, listeners, and in-flight permission prom
 1. Package scaffold `packages/ui/acp/` per [the cookbook](../../../cookbook/adding-a-package.md); add `@agentclientprotocol/sdk` and `zod`. Add the abstract create/resume factory to `dsh-agent` (the interface) so the bridge can `inject: ['agents', 'sessions', 'tools', 'sessionPersistence']` without depending on the concrete loop; `sessionPersistence` is required because `session/load` advertises `loadSession: true`. (Fallback only if the factory is judged not worth it: inject `agentLoop` directly and record the architecture-rule exception in `docs/architecture.md`.)
 2. Connection plus `initialize`/`session/new`: wire `AgentSideConnection` to stdin/stdout; protocolVersion negotiation; the single-session guard; create the live session through the new `{ sessionId, meta }` factory seam (so the ACP `sessionId` and validated `cwd` become the session's id and header); the `sessionId↔agent` and `Session↔sessionId` maps.
 3. Internal edit — turn-end reason fidelity (sanctioned: edit internals to fit ACP). Extend `TurnEndReasonMap` in the proper places: (a) declaration-merge a `max-tokens` variant in the owning package (`packages/core/session/src/types.ts`, alongside `completed|aborted|error|disposed`) — add `max-tokens` because `FinishReasonMap` produces it (DeepSeek maps `length` → `max-tokens`); do not add `refusal`, since no current adapter produces it (unknown DeepSeek finish reasons collapse to `error`), but leave a comment in `TurnEndReasonMap` noting `refusal` should be added when an adapter first emits it (`FinishReasonMap` is merge-extensible); (b) make `agent-loop`'s `loop.ts` populate the reason from the model `finish` chunk — `assembler.finish` lives inside `runStep`, so `runStep` must return it up to `runTurn`, and the rule is "the last step's finish reason wins, but any `max-tokens` in the turn surfaces as `max-tokens`"; (c) no consumer exhaustively switches over `TurnEndReason` today (the invariants plugin switches on `SessionEventType`, and `deriveMessages` ignores `turn/end`), so adding `max-tokens` is a non-breaking extension — but recheck before landing; (d) update [docs/architecture.md](../../../architecture.md) (the CI-verified loop-lifecycle/event-taxonomy doc) and the affected package READMEs/JSDoc (`dsh-session`, `dsh-agent`, `dsh-agent-loop`) per the repo doc-sync policy. This replaces a fragile "observe the finish chunk in the bridge" hack with a real, documented contract.
-4. Prompt-turn streaming plus load: translate `agent/stream-chunk` and `session/event` into `session/update`; resolve `session/prompt` on settle, mapping the harness `TurnEndReason` to the ACP `StopReason` wire enum (`completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`→`cancelled`) — a small total function with a test asserting the exact wire strings, since the SDK rejects an unknown `stopReason`. Concrete correlation, since the loop batches queued messages into one turn and `send()` does not synchronously flip to running: install listeners before `send()`; gate on an observed `agent/turn-start` (confirms work was accepted) then resolve on the next `agent/turn-end`; reject an empty/whitespace prompt up front rather than calling `send()` (no turn would ever start, so the RPC would hang). Implement `session/load` on the session-persistence resume seam.
+4. Prompt-turn streaming plus load: translate `agent/stream-chunk` and `session/event` into `session/update`; resolve `session/prompt` on settle, mapping the harness `TurnEndReason` to the ACP `StopReason` wire enum (`completed`→`end_turn`, `max-tokens`→`max_tokens`, `aborted`→`cancelled`) — a small total function with a test asserting the exact wire strings, since the SDK rejects an unknown `stopReason`. Concrete correlation, since the loop batches queued messages into one turn and `send()` does not synchronously flip to running: install the `session/event` listener before `send()`; capture the prompt's owning turn from its `turn/start` record, then resolve on that turn's `turn/end` (with `agent/status` idle/disposed as a fallback); reject an empty/whitespace prompt up front rather than calling `send()` (no turn would ever start, so the RPC would hang). Implement `session/load` on the session-persistence resume seam.
 5. Permission gate: a single `tools/execute` listener registered with `prepend: true`, owning a `WeakMap<Agent, sessionId>` of bridge-created agents; no-op (`next()`) for unowned/no-agent calls; for owned calls → `session/request_permission` → allow (`next()`) / veto; settle the stored resolver exactly once on outcome, cancel, or connection close.
 6. Example wiring (extract a shared base). `@cordisjs/plugin-include` is itself a plugin entry that resets `ctx.baseUrl` and loads a path, so a child `cordis.yml` can nest-include a shared base; the extraction is safe because every dependent plugin declares `inject` (loader groups initialize via `Promise.all`, so YAML order is NOT the dependency mechanism — never rely on it). Extract the provider/tool core (`llm, sessions, system-prompt, tools, agents, invariants, llm-deepseek, bash-local, tool-bash`) into `examples/base.yml`; have both `coding-agent` and a new `examples/acp-agent/` include it and add their own UI plugin plus logger. Keep `agent-loop` per-example (NOT in the base): `AgentLoop` creates its configured agents in its constructor, and the two examples disagree — `coding-agent` needs a pre-created `main` (its `stdio-chat` calls `ctx.agents.get('main')`), while `acp-agent` must pre-create none (ACP `session/new` creates agents). So `coding-agent` declares `agent-loop` with `agents: [{ id: main, … }]` and `acp-agent` with `agents: []`. `acp-agent` loads `dsh-session-persistence-jsonl` (from [session persistence](../../implemented/architecture/2026-06-14-session-persistence.md) — required for `session/load`), omits the stdout logger (see Risks), and adds `pnpm run demo:acp` plus the Zed `agent_servers` snippet.
 7. Tests (the repo cares a lot here): a property-based test for the protocol shape (precedent: [property-based testing](../../implemented/testing/2026-06-11-property-based-testing.md)) — fuzz arbitrary harness event sequences and assert ACP-stream invariants (never a `tool_call_update` before its `tool_call`; exactly one `session/prompt` resolution per prompt; monotonic, well-formed ordering; `stopReason` in the legal set); codec unit tests over an in-memory `Duplex` pair (drive `AgentSideConnection` without a subprocess; assert exact frames for `initialize`, `session/new`, a full prompt turn); the mandatory HMR-safety test (dispose the fiber; assert the connection closed, all `ctx.on` listeners gone, any in-flight `request_permission` settled); failure-path tests (connection closes mid-stream; closes with a permission pending; a notification `send()` rejects but the turn survives; `finish{kind:'error'|'aborted'}`; a `tools/execute` throw with no `tool/result`; a second `session/new` rejected; a `session/prompt` while one is in flight; an empty prompt rejected without hanging; a `session/load` re-derives identical history and replays it); and an e2e (`*.e2e.ts`, self-skips without `DEEPSEEK_API_KEY`) that boots `examples/acp-agent`, connects a `ClientSideConnection`, sends a real prompt, owns and disposes the harness in `afterEach`, and verifies the world (files on disk), not the agent's self-report.
diff --git a/packages/core/agent-loop/src/loop.ts b/packages/core/agent-loop/src/loop.ts
index eba75f9615..3921122559 100644
--- a/packages/core/agent-loop/src/loop.ts
+++ b/packages/core/agent-loop/src/loop.ts
@@ -529,11 +529,14 @@ async function runTurn(ctx: Context, agent: ReactLoopAgent, handle: LoopHandle,
     // Gating on a "turn started" boolean would skip turn/end and leave a
     // permanently OPEN turn that poisons the next turn/replay (the turn-enclosure RFC). We
     // check the log for THIS turn's turn/start: present means a turn/end is owed
-    // (or was already appended — closeTurn/failTurn are idempotent, so running
-    // them again is a safe no-op that still preserves the disposed/error reason
-    // chosen below). Absent means the turn/start append threw BEFORE its push (a
-    // non-serializable trigger — impossible for our fixed trigger); nothing was
-    // opened, so rethrow to the runLoop backstop.
+    // and the normal-exit `closeTurn()` did NOT run (we are here because a throw
+    // preceded it — the two `closeTurn()` sites are on mutually exclusive paths),
+    // so this catch appends turn/end with the disposed/error reason chosen below.
+    // `closeStep()` IS idempotent (guarded by `stepOpen`) — it may have run
+    // already in a step branch, so running it again is a safe no-op. Absent
+    // turn/start means the append threw BEFORE its push (a non-serializable
+    // trigger — impossible for our fixed trigger); nothing was opened, so rethrow
+    // to the runLoop backstop.
     const turnStartLogged = session.events.some(e => e.type === 'turn/start' && e.data.turn === turn)
     if (!turnStartLogged) throw error
     closeStep()