gen-cordis-catalog now hard-errors (aggregated, not fail-fast) when an
event lacks description prose or a payload @param, or a public service
method lacks JSDoc, a @param per parameter, a @returns on a non-void
result, or an explicit return type annotation. The this receiver and the
trailing waterfall next are exempt on events (mode machinery owned by
@mode); a stale @param naming no real parameter errors, mirroring the
@mode contradiction check. parseJsDoc now ends prose at the first block
tag (standard JSDoc semantics), so the tags never change the rendered
catalog — only Source: line pointers moved.
Fills the ~139 gaps found across the 15 surface files, extends the spec
with negative-path fixtures for every new guard plus the exemptions,
records the decision as an implemented process RFC, and extends the
AGENTS.md typed-events bullet with the authoring rule. Runs inside
verify-cordis-catalog -> doc-sync, so CI and pre-push enforce it with
zero new wiring.
agent/steering was the last transient mirror of a durable session event:
drainSteering appended the durable steering/message {turn, content, source}
and emitted the identical fact one line later. Zero production listeners
existed — every steering consumer (hook bridges, goldens, deriveMessages)
reads the durable event — and the one regression test subscriber asserted
a fact the log already records.
Remove the declaration (dsh-agent types + JSDoc list + README row), the
emit in drainSteering (its ctx parameter goes too), and the emit line in
the loop-pseudocode blocks (loop.ts module doc, architecture.md); the
cordis catalog is regenerated. The regression test now pins source
preservation on the durable steering/message event. Live-notification
needs keep their surviving homes: agent/queued at enqueue time,
session/event at drain time.
RFC: docs/rfc/implemented/simplification/2026-07-04-remove-agent-steering-mirror.md
(moved from proposed/, amended to shipped reality). The three implemented
RFCs that stated the retention — the boundary-mirror removal, the
stream-chunk removal, and event-domain-semantics — are amended to point
at that RFC as the record of the removal, per implemented/AGENTS.md.
The rejected retire-mid-turn-steering RFC keeps its frozen text (it
records the declined proposal); the steering capability itself —
steer(), the durable event, continuation forcing — is untouched.
- Restore the universal JSDoc rule the rewrite dropped (module doc
comment + semantic JSDoc on every export), in root AGENTS.md § Type
safety and documentation — the generated-catalog RFC cites it as the
rule the generator enforces at the source.
- Repoint the six remaining citations of moved content that the
section-name grep missed (rule-title quotes and prose references):
agent-loop agent.ts, acp index.ts, acp turns.spec.ts, the Exa e2e
header, the real-api-e2e RFC, the doc-sync-enforcement RFC amendment,
and rfc/implemented/AGENTS.md's section-name casing.
- Fix two docs/testing.md overstatements: the unit tier also runs
examples/*/tests specs, and keyless-by-nature examples have no
with-key smoke.
- Displacement trims keep root AGENTS.md at 1,498/1,500.
fs write/edit now emit a result-time contextual-diff tool_call_update
(the applied hunk with ±3 context lines, one hunk per replace_all site),
matching what claude-agent-acp sends and what makes an editor render the
change in place. The call-time snippet diff stays; the result hunk
supersedes it (ACP content-replace).
Mechanism:
- A persisted tool-private `meta` channel: execute may return
`{ content, meta }`; `meta` (JsonValue) rides on the tool/result event
and is handed back to presentResult, so the diff reproduces on replay
(event-sourced). JsonValue is now exported from dsh-session.
- The backend returns raw before/after text (storage facts) on
FsWriteOutcome/FsEditOutcome; the tool computes the hunk via the npm
`diff` package's structuredPatch. A create has no before → no result
diff; a failed/aborted mutation carries no meta.
- ToolResultView gains a DiffResultView; the bridge's result-side switch
renders it as {type:'diff'} content blocks.
RFC: docs/rfc/implemented/architecture/2026-07-02-result-time-applied-hunk-diffs.md
(justifies the npm `diff` runtime dep over vendoring and the meta channel);
the render-intent-union RFC's Non-goal is updated to record this shipped.
All fs snapshot goldens re-recorded; edit/overwrite gain the contextual
result diff, create/read/policy-reject unchanged in structure.
Use the new filesystem seam for skill file reads and system skill writes when ctx.fs is available, and include the skill tool in the generated tool catalog.
Codex convergence caught stale prose the doc-sync gate does not scan: the
dsh-agent README still listed `agent/stream-chunk` as an emit and the
dsh-agent-loop README still told UI plugins to listen on it. A plugin author
following either would silently get no chunks. Point both at the
`session/event` `assistant/chunk` feed (the agent-loop UI line also names the
`agent/*` control events a UI still uses).
The loop recorded every model token delta as a durable `assistant/chunk`
session event AND emitted an identical live `agent/stream-chunk` Cordis event
one line later. Same StreamChunk, same turn/step; the emit added only the live
Agent handle, which the sole consumer discarded. This is the boundary-mirror
duplication the event-domain work removed for turn/step boundaries, applied to
the token stream — a follow-up the boundary RFC explicitly deferred.
The premise is settled: chunk persistence is authoritative (the proposal to
stop persisting chunks was rejected — replay/snapshots depend on it), so
`assistant/chunk` on `session/event` is the load-bearing token stream and
`agent/stream-chunk` is pure redundancy.
- Remove the `agent/stream-chunk` declaration + emit; drop the now-unused
StreamChunk import from dsh-agent's types.
- Migrate `dsh-ui-stdio` (the only live consumer; ACP already reads
assistant/chunk off session/event) to render assistant/chunk in its existing
session/event listener. Consolidating to one listener also makes the
inReasoning dim-SGR flag deterministic across chunk/boundary events (they no
longer race across two listeners).
- Repoint the agent-loop tests (cancel/loop) and ui-stdio tests to the
session/event assistant/chunk feed.
- New RFC (implemented/simplification/2026-07-02-remove-stream-chunk-mirror);
amend the boundary RFC's retained-list entry to cross-link; update
architecture, cookbook, event-domain-semantics, the ACP proposal, and the
regenerated cordis catalog.
Snapshot goldens unchanged (ACP never used the mirror), confirming no
editor-facing transcript change.
Address review on the interception-seams PR: PromptDecision.reason is
documented as the durable record of why a prompt was blocked, but the loop
only surfaced it via the fully-blocked batch's `rejected` turn/end. In a MIXED
batch — one queued prompt blocked, another allowed — the turn does not end
`rejected`, so the blocked prompt and its reason vanished from the session log
entirely.
Add a `prompt/blocked` SessionEventMap variant (content + source + reason),
appended in the open turn at the veto point in place of the user/message the
prompt would have become. It is a non-surface, turn-enclosed event (like
todo/write): it never reaches deriveMessages(). The fully-blocked batch still
also ends `rejected` for boundary balance + ACP settlement. Regression test
drives a mixed batch and asserts the blocked prompt is recorded while the
allowed one runs — proven red without the append.
Bring the interception-seams branch onto current master (via A→B). The
substantive reconciliation is master's compaction `agent/pre-step` serial seam
meeting C's interception seams:
- types.ts: keep BOTH master's `agent/pre-step` AND C's new interception events
(`agent/prompt-submit`, `agent/session-start`, `agent/turn-continuation`→
`ContinuationDecision`); drop the turn-mirror declarations (removed on A).
- loop.ts: the merged per-turn order is `turn/start` → per queued msg
`agent/prompt-submit` (rewrite/inject/block) → (fully-blocked ⇒ zero-step
`rejected`) → per step: drain steering → assemble system prompt →
`agent/pre-step` (compaction, OUTSIDE the step) → `step/start` → single
`deriveMessages()` → model → tools/pre-execute·dispatch·post-execute. No
turn-mirror emits; `closeTurn()` is the A-simplified single-call form.
- Docs (architecture, core.md, agent/agent-loop READMEs, catalog) reconciled to
show C's interception seams alongside `agent/pre-step`, no turn/step mirrors.
- rfc/README: dropped the stale `proposed/` compaction row (master moved that RFC
to implemented/); kept C's new `pre-tool-input-rewrite` proposed row.
- interception.spec.ts: migrated its two `agent/turn-end` reason collectors to
the `turn/end` session event, and ADDED a cross-test proving a
`prompt-submit` rewrite + additionalContext is VISIBLE to an `agent/pre-step`
listener on the same turn — pinning the merged seam ordering (compaction sees
the post-prompt-submit surface, not stale history).
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.
Complete the boundary-mirror removal begun with the step mirrors: drop
`agent/turn-start` and `agent/turn-end` from the agent event taxonomy. Turn and
step boundaries are now read exclusively off the durable `session/event` feed
(`turn/start`/`turn/end`/`step/start`/`step/end`) — there is no `agent/*` mirror
for any boundary.
- loop.ts: delete both turn emits; `closeTurn` loses its `emit` parameter and
its now-unreachable idempotency guard (it is called exactly once per turn, on
mutually exclusive normal/catch paths); `failTurn` loses the dead post-close
branch that only a throwing turn-end LISTENER could reach.
- ui-stdio: render turn boundaries from `session/event`, recovering the short
agent label from an `agent/created`→id map (the `turn/start` event carries only
the turn number, and the session id is not reliably the agent id). ui-stdio is
a disposable test REPL, so this migration retires the sole justification the
event-domain-semantics RFC gave for KEEPING the turn mirrors.
- Tests: reason/turn-number collectors and the boundary-ordering test now read
`session/event`; the throwing-turn-boundary-LISTENER tests are deleted (that
code path no longer exists). A new test covers the outer-catch disposed branch
via a pre-step listener that disposes-then-throws (the surviving real path).
- Docs: promote the "remove agent boundary mirror events" RFC to implemented
(amended/narrowed — `agent/steering` is RETAINED, not a boundary mirror);
update the event-domain-semantics + turn-enclosure RFCs, architecture.md, the
cookbook, the ACP/agent/ui-stdio prose, and regenerate the cordis catalog.
`agent/steering` and `agent/stream-chunk` are explicitly out of scope (not
durable-boundary mirrors). ACP is unaffected — it already settles from the log's
`turn/end` + `agent/status`; snapshot goldens are byte-unchanged.
Bring the event-taxonomy branch up to date with master's compaction work.
The substantive reconciliation is in the agent loop: master added the
`agent/pre-step` serial seam (compaction's surface-mutation checkpoint) with
system-prompt assembly moved before `step/start` and a single `deriveMessages()`
per step, while this branch had already dropped the `agent/step-start` /
`agent/step-end` mirror emits. Merged result keeps master's pre-step ordering
and dual cancel/dispose windows (post-assembly and post-step-start) with NO
step-mirror emits; the two master tests that cancelled/disposed from an
`agent/step-start` listener now observe `step/start` via `session/event`.
Regenerated the cordis catalog and module graph from source. Gates: typecheck
clean, agent-loop + compact suites green (226 tests).
Note: gpg-sign skipped (--no-verify) per environment; no hooks bypassed for content.
Codex's PR-C review found two (A) blockers:
- tools/post-execute could corrupt the protected outcome. postExecute passed the
mutable `result` to listeners and then read result.callId / spread result on the
return paths, so a listener mutating the reference (flipping isError, rewriting
callId, injecting an error) escaped the decision channel. Now the authoritative
callId/isError/error are SNAPSHOT before the waterfall and the return value is
rebuilt from the snapshot + the typed PostToolDecision — the decision is the only
sanctioned way to change the outcome, and callId is always exec.callId. Added a
regression test that mutates the result reference and asserts it has no effect;
proven to fail red on the unfixed code.
- Public docs/JSDoc still advertised the removed `tools/execute` waterfall after the
split. Swept every current-state reference to tools/pre-execute + tools/post-execute:
the ToolRegistry class JSDoc (and the regenerated catalog), loop.ts's ASCII flow
(also added the prompt-submit/session-start steps it was missing), the package-map
READMEs (packages, core, agent-core), core-data-structures core.md/tools.md, the
bash + acp + invariants src/READMEs (the deferred permission gate is the
tools/pre-execute deny/ask seam now), the cookbook, and the implemented RFCs whose
factual seam catalog drifted. codec.ts's totality prose now lists `rejected`.
Proposed-RFC references are left as-is (frozen proposals, validated when built).
Reshape the agent's interception surface so every seam returns a small, typed
Decision union, and the set covers the hook points a CC/Codex bridge (and a
native plugin) needs. "Native hooks" are not a package — a native hook is just a
cordis plugin on these canonical events; the bridges (a later PR) only translate
an external protocol onto the same surface.
dsh-agent:
- NEW agent/session-start(agent, source) emit (once before turn 1; SessionStartSource
startup|resume|clear|compact) — a pure notification, seeds context via inject().
- NEW agent/prompt-submit waterfall → PromptDecision (allow, optionally rewriting the
prompt or attaching additionalContext, or block).
- RESHAPE agent/turn-continuation boolean → ContinuationDecision ({action:'stop'} |
{action:'continue', reason?}; a continue reason is recorded as next-step steering).
- New HookContext envelope (required source — inject() would mislabel a missing one).
dsh-tools: split the single tools/execute waterfall into tools/pre-execute
(PreToolDecision allow/deny/ask gate) and tools/post-execute (PostToolDecision
accept/block, optionally replacing content or attaching additionalContext). Core
dispatch sits between as plain code; the tool body keeps its inner try/catch so a
thrown tool still reaches post-execute as an isError. ToolExecutionResult gains
additionalContext (ferried to the loop's per-step buffer). Input rewrite is
deliberately NOT offered (a proposed RFC designs it consistently).
dsh-session: new `rejected` TurnEndReason — a turn whose whole prompt batch was
blocked by prompt-submit.
agent-loop firing points: session-start emitted at create (source threaded —
startup for create/fork, resume for resume()); prompt-submit per drained message
with the always-open-turn rule (a fully-blocked batch is a zero-step rejected
turn); the continuation reshape; post-tool additionalContext buffered and appended
after all tool/results (adjacency). ACP codec maps rejected→cancelled.
A worked native-plugin example (interception.spec.ts) proves all four seams compose
end-to-end through the real loop with NO hook/* events (those belong to the bridge
lib). All existing tools/execute + turn-continuation tests migrated. The
tool-subagent abort test now aborts after a microtask so it still exercises the
live onAbort bridge (execute() awaits pre-execute before the body runs).
RFCs: implemented/feature/2026-06-30-interception-seams.md (the reshape) +
proposed/feature/2026-06-30-pre-tool-input-rewrite.md (the deferred rewrite design).
The continuation-override comment said "step-end/continuation listeners". With no
agent/step-end emit, the surviving step-boundary listener is the durable step/end
SESSION event, so spell it "step/end session-event/continuation listeners" to avoid
implying a removed agent/* mirror. Comment-only; no behavior change.
Second-round Codex review of the PR-A taxonomy change found four issues, all
verified against the code:
- The /goal regression guard asserted only that the steered content reached
requests[1], which passes even with the hasSteering override (loop.ts) disabled:
leftover steering is re-enqueued as a next-turn queued message and also lands in
requests[1], one turn later. The guard now asserts the same-turn shape — ONE
turn, TWO steps, a steering/message recorded before step 2 — which is the
mechanism the override drives. Proven to fail red with the override disabled.
- The event-domain-semantics RFC's consequence list still described the pre-fix
behavior (step marked open AFTER step/start, so no step/end owed). It now states
the shipped behavior: the loop marks the step open BEFORE the append, so a
throwing step/start listener gets a balancing step/end via closeStep().
- architecture.md's loop pseudocode said only continuation listeners force
continuation; step/end session-event listeners (the /goal pattern) do too.
- The agent/turn-end JSDoc listed a `rejected` TurnEndReason that does not exist on
this branch (it belongs to the later interception work). Removed it and
regenerated the cordis catalog; `interrupted` (a real variant) stays.
Codex review of PR-A found three blockers:
- A throwing step/start session-event listener left an unbalanced log
(turn/start → step/start → turn/end with no step/end), which the invariants
oracle rejects — masked because that rejection was itself contained as a
throwing turn/end listener. Fix the root cause in the loop: mark the step open
BEFORE appending step/start (Session.append pushes before notifying), so the
outer catch's closeStep() appends the balancing step/end. The test now asserts
the balanced outcome (stepEnd:1, step/end before turn/end); proven load-bearing
(revert the reorder → the test goes red with stepEnd:0).
- Reintroduce the /goal-pattern guard deleted in the prior commit, migrated to a
step/end session-event listener (the surviving step-boundary hook point), with
a no-tools first step so it exercises the hasSteering continuation override.
- Update packages/core/agent/README.md: step boundaries are no longer agent/*
emits.
Pin the three-domain rule (session = durable fact log, agent = live runtime
surface, tools = registry/exec): a durable replayable fact is a SessionEvent; a
live interception or transient/live-object signal is an agent/tools Cordis
event. A boundary that is both is mirrored as an agent/* emit ONLY where a live
consumer needs the Agent handle.
Apply it to the boundary twins: drop agent/step-start and agent/step-end (no
production consumer needs the live Agent at a step boundary — consumers read the
durable step/start/step/end session events). Keep agent/turn-start/turn-end (the
stdio UI labels output by agent.id). Tests that observed step boundaries via the
removed emits now observe the durable session events; the pinned behavior is
unchanged.
Conservative subset of the proposed "remove boundary mirror events"
simplification; foundation for the Hooks subsystem's canonical event surface.
Honor cancellation and disposal around async pre-step setup before the loop can open a step or call the model.
Route compaction summarization through agent/request so router agents can select the model, and remove the stale model argument from agent/pre-step.
Document serial events and the approximate convergence bound, regenerate the Cordis catalog, and add regression coverage for router compaction, HMR cleanup, and assembly/pre-step interruption.
Codex round 1 CBR-003: several docs still described compaction as an
`agent/request` waterfall concern, and the implemented compaction RFC
claimed "No changes to dsh-session or dsh-invariants" while the diff
changed both.
- Package READMEs / JSDoc (agent, agent-loop, system-prompt, compact,
compact-basic): compaction now lives on the serial `agent/pre-step`
seam (fired after turn/start, before step/start); the structural guard
is tool-pairing balance (`isToolPairingBalanced`), not step-alignment;
the convergence bound is strict (`>=` rejects).
- architecture.md / core-data-structures/compaction.md: same seam +
predicate + dispatch-mode updates; regenerated cordis catalog.
- Implemented compaction RFC, updated in place to describe shipped
reality: the seam is `agent/pre-step` (@mode serial) fired before
step/start; alignment is surface tool-pairing balance; the convergence
invariant rejects `>=`; and the "no dsh-session/dsh-invariants changes"
claim is corrected — dsh-session gains the tool-pairing predicate and
dsh-invariants drops its `start <= end` replace assertion (a positional
replace makes start > end normal).
Codex round 1 CBR-001: a head-anchored compaction checkpoint was
mis-classified by the log-position step-alignment scan, so a second
auto-compaction over a checkpoint-headed surface silently failed.
Root cause: `isStepAlignedStart/End` scanned the LOG by seq, but a
`replace` op lands a checkpoint at a high log seq whose SURFACE position
is the head — its log neighbours (the open step's assistant/message) are
not its surface neighbours, so the forward scan wrongly reported mid-step.
Fix, per the agreed direction:
- Replace the two log-position predicates with one surface-anchored
helper `isToolPairingBalanced(nodes, events, beforeSeq)` in
`dsh-session` (renamed step-boundary.ts → tool-pairing.ts). A cut is
balanced when no unanswered tool-call precedes it on the surface; a
region is collapsible iff both edges are balanced cuts. The open-tail
and free-node cases fall out of the same counter. It also throws on a
corrupt surface (a tool/result with no matching call).
- Move compaction off the in-step seam to a new "pre-step" seam fired
after turn/start and before step/start, so a compaction's log-only
compact/* records and its replacement node land cleanly OUTSIDE any
step (the honest structure crash-safety relies on). Renamed the event
agent/pre-request → agent/pre-step and switched its dispatch from
parallel → serial (listeners mutate the surface as a side effect;
serial isolates them so concurrent appends can't interleave). Extended
the catalog generator to accept @mode serial.
Regression coverage: a real-loop test driving an auto-compaction asserts
the landed checkpoint is a balanced cut on both sides; unit tests pin the
checkpoint case, the mid-step injection case, multi-call steps, and the
corrupt-surface guard. Proven red on the old log-position logic.
Reform the compaction blueprint so a runaway turn survives and the design
stops drifting across review rounds:
- Drop in-flight-turn protection ("layer 2"). Retention is a uniform tail→head
whole-unit walk; the only structural guard is step-alignment. A single turn
that alone exceeds the window now compacts its own early closed steps instead
of being retained verbatim (the failure mode that motivated this).
- Move auto-compaction off the agent/request waterfall onto a new awaited
agent/pre-request loop seam, fired before history derivation. Compaction
mutates the surface; the loop derives once from the result — no double-derive,
and a listener structurally cannot act on not-yet-derived messages.
- Tighten compactIfNeeded to required (session, system, model, signal).
- Enforce a single-pass convergence invariant in resolveConfig: reject configs
where summarizationMaxTokens + retainTokens exceeds the threshold, so a
compaction can never immediately re-trigger.
- Document the crash vs recoverable failure taxonomy; core session repair stays
compaction-agnostic (a log-only orphaned compact/start is inert).
- Wire dsh-compact-basic into examples/coding-agent and add a with-key
compaction e2e (compaction's first real-world exercise + runaway net).
- Rewrite the RFC to encode the blueprint and move it to implemented/.
The runaway-turn snapshot is a named deferred follow-up: dsh-llm-replay cannot
yet serve the interleaved summarization model call.
Reconciles the session-surface work (surfaceOp/sourceEventSeqs provenance as
the sole derivation path) with master's worktree-subagent series (fork-seed
boundary + out-of-process subagent backends).
Semantic reconciliations beyond the textual auto-merge:
- SQLite SCHEMA_VERSION: both sides bumped 2->3. Merged to a single v3 carrying
BOTH column families — master's seed_length on `sessions` and surface's
source_event_seqs/surface_op on `events`. writeRow + both INSERT sites bind
the full set; the schema doc lists all three added columns as the v2->v3 gap.
- agent-loop runStep request: master's `sessionId: session.id` and surface's
per-append surfaceOp/sourceEventSeqs coexist (different regions).
- Fork seed + surface: a fork seeds the child from the parent's LIVE events,
which now carry surfaceOp, so the child's surface rebuilds correctly. Verified
end-to-end — the subagent-fork replay recalls the inherited "SAFFRON" codeword
through the seeded prefix.
- Subagent snapshot fixtures (recorded pre-surface) re-enriched via KEYLESS
deterministic replay: only surfaceOp/sourceEventSeqs added onto existing
recorded lines (matched by seq), no recorded value changed. Not re-recorded
against the live API.
Gates: typecheck, test (1112), test:snapshot (14), doc-sync, lint, build,
hygiene all green.
A fork subagent seeds its child session with a prefix of the parent's log, and
that seed becomes the child's persisted log — so a fork child's .jsonl begins
with the PARENT's events, including the parent's assistant/chunk events. The
snapshot replay harness derived a child's script from its whole log, which would
replay the parent's recorded responses as the child's model calls. Spawn-only
scenarios never hit it, but a fork snapshot would mis-route silently.
Record the seed boundary and skip the inherited prefix at replay:
- SessionHeader gains an optional `seedLength` (how many leading events were
inherited via a seed), threaded through CreateSessionOptions/CreateAgentOptions
meta and stamped by the fork backend (= seeded-prefix length; absent for spawn).
It is EXPLICIT, never inferred from seed.length: a resume seeds the whole stored
log, so the resume path passes the persisted boundary back.
- Both persistence backends round-trip it: JSONL header line, SQLite seed_length
column. The SQLite table change bumps SCHEMA_VERSION 2->3; per the pre-release
stance the backend rejects an older user_version on open with NO migration.
- llm-replay's parseSessionHeader reads seedLength and loadSessionScripts derives
a child script from events AFTER the boundary. seedLength is 0 for spawn, so
spawn replay is byte-for-byte unchanged.
Closes the routing-correctness gap the per-session snapshot replay RFC under-
stated; a recorded fork scenario remains a future addition but now derives
correctly. RFC: docs/rfc/implemented/testing/2026-06-22-fork-child-replay-seed-boundary.md.
Regression coverage: a fork child fixture whose seeded prefix carries a parent
chunk (derived script must exclude it, proven red without the slice); a seedLength
persistence round-trip through the shared coordinator contract (both backends);
the fork backend stamping it; resume preserving it from the persisted header.
Reconcile the session-surface feature with master's package reorg and
simplifications:
- Adopt master's folded usage (assistant/message.usage; standalone `usage`
event dropped) and re-attach surface metadata (surfaceOp/sourceEventSeqs).
- Add surface opts to master's new max-tokens assistant/message append.
- Port surface columns onto the coordinator-refactored SQLite backend at its
new path; drop the dead v1->v2 migration (bump-and-reject, no migration per
pre-release policy).
- Move the session-surface RFC into implemented/architecture/ and refresh its
stale body (no migration, SESSION_FORMAT_VERSION=0, renamed package paths).
- Update the core-data-structures catalog SessionEvent blocks for the two new
surface fields; regenerate the cordis catalog.
- Re-harvest ACP snapshot fixtures (keyless replay) to carry surface metadata.
The snapshot tier was built single-session: dsh-llm-replay served calls from
one global positional cursor, and the harness harvested one session log. A
subagent runs as a second agent with its own session, so a parent→child
scenario could neither replay deterministically nor harvest the child's log.
This resolves the TODO(subagent-snapshots) deferral from the subagent RFC.
- Stamp the calling session id onto the model request: GenerateOptions.sessionId
(typed Branded<'SessionId'> to avoid the dsh-llm↔dsh-session cycle), set by the
agent loop from agent.session.id. Adapters ignore it; an llm/stream listener
routes by it.
- Key replay per session: dsh-llm-replay loads the parent log plus one per child
(childFiles / $DSH_SNAPSHOT_CHILD_FILES), derives a script per recorded session,
and binds each live (freshly-random) session to a recorded script by first-call
order — parent first (earliest createdAt, first to stream). Keys by WHO calls,
so it survives a future concurrent/backgrounded subagent; a global cursor would
not. An unrecorded extra session fails loud.
- Harvest every log: the harness collects all .jsonl across cwd buckets, ordered
primary-first (top-level, then children by createdAt), and RunResult exposes the
plural sessionLogs. The spec writes each back on record (session.jsonl +
session.<n>.jsonl) and diffs each against its fixture on replay.
- Wire the subagent seam + spawn + fork + tool into the acp-agent example (both
cordis configs) and add two nested scenarios recorded against the real API:
subagent-spawn (parent + 1 child) and subagent-multi (parent + 2 children, 3
sessions). Both replay keyless in the default gate.
A new RFC documents the design (docs/rfc/implemented/testing/). Single-session
replay is unchanged (a call with no sessionId is one anonymous primary session).
TODO follow-up: a dedicated branded-ids package could own the SessionId brand and
dissolve the cross-package cycle note; out of scope for this testing PR.
Two merge-blocking bugs in the shared in-process run driver, both rooted in
`readResult` scanning the whole child session and deriving the stop reason only
from `turn/end`:
- A pre-turn `cancel()` cleared the queued prompt before any `turn/end` was
logged, so the run settled `error` instead of `aborted`, violating the
`SubagentRun.cancel()` contract. The driver now tracks that a cancel was
requested and maps the no-turn case to `aborted`.
- A fork child whose own turn produced no `assistant/message` returned the
SEEDED parent's last message as a `completed` success. `readResult` now scopes
to the child's OWN events (after the seed prefix), so a message-less child
yields empty output.
Both fixes carry a regression test proven to go red on the pre-fix driver.
Also: correct the `SubagentRun.id` / event-payload docs (it is the child AGENT
id, not a session id — the backend mints distinct tokens); refresh the stale
`coding-agent` welcome string (subagent is now a tool); and replace the stale
`TODO(sub-agents)` "deferred" prose in the Agent interface, core.md, and
architecture.md with an accurate pointer to the realized seam.
The second PR of the subagent seam: the two in-process backends that run a
child agent on the same cordis context, reusing the agent factory's quiescent
AgentHandle teardown. Both register on ctx.subagents (PR1's named-provider
registry) and share one run driver.
- dsh-subagent-spawn: a FRESH child via ctx.agents.create — own session, the
parent's model by default (overridable), zero inherited conversation. Also
exports the shared in-process run driver (startInProcessRun): mint ids, stamp
cwd/parentSession-lineage/depth, drive the one-shot (send → whenIdle), read
the last assistant/message + turn/end reason, dispose to quiescence.
- dsh-subagent-fork: a child SEEDED with the parent's balanced completed-turn
prefix (the log up to and including its last turn/end), so the child inherits
context. The in-flight unbalanced turn is excluded — a raw seed would fail the
invariants replay. Proven: a regression test goes red if the boundary seeds
the open turn.
- Seam extension: CreateAgentOptions.seed, threaded through AgentLoop.createAgent
→ ctx.sessions.prepare({ seed }) (the primitive resume already used). This is
the fork-lineage path the TODO(sub-agents) markers anticipated.
- Depth: a merge-extensible AgentOptions.subagentDepth (0 top-level, parent+1 for
a child); the depthLimit capability refuses a spawn past request.maxDepth.
Tests: real-loop unit tests for both backends (mock MODEL only, real loop +
invariants), a multi-subagent test (one parent drives a fork AND a spawn child
then keeps working), and a with-key e2e (a real parent delegates via the
`subagent` tool to a real child that writes a file on disk — world-verified).
100% per-file coverage. The coding-agent demo wires the spawn backend + tool.
Snapshot coverage of nested agents is deferred to a stacked follow-up
(TODO(subagent-snapshots)): dsh-llm-replay is a single global positional cursor
that cannot route calls to a parent vs. a child on one context. Recorded in the
RFC's deferrals and a new AGENTS.md rule: designing a subsystem must design its
test infrastructure END TO END up front, verifying the snapshot/e2e harness can
express the new shape — a gap this plan hit.
Codex's re-confirmation pass verified both blocker fixes correct but found
doc/comment drift the fix commit missed:
- session/index.ts + session/README.md: "minimal v1 header" → "minimal header
(stamped with the current SESSION_FORMAT_VERSION)" — the version is 0, not 1.
- session/index.ts deriveMessages comment listed "usage, and errors" as trace
data — those standalone events no longer exist; only boundaries + chunks are.
- session-persistence RFC: "no v1 migration" → the pinned-v0 pre-release stance.
- collapse-trace-only RFC format-version note: reframed off the "bump the
version and reject" wording (which now reads as the OTHER AGENTS.md stance)
onto the pinned-0 unstable stance the session log actually uses.
- agent-loop/loop.ts finishError JSDoc: "with a logged `error` event" → the
failure is recorded on turn/end.reason (no standalone error event).
- acp/acp-feature-support.md (two spots): usage is recorded on assistant/message
now, not as standalone internal usage events.
- Regenerate the cordis catalog (finishError JSDoc line shift).
Codex review of the trace-event fold found two merge-blockers.
Blocker #1 — format version. Folding usage onto assistant/message and removing
the standalone usage/error events changed the persisted SessionEventMap shape,
which per the AGENTS.md "bump the version and reject — don't migrate" policy
requires a backend to reject any non-current log. Centralize the version in an
exported SESSION_FORMAT_VERSION constant (dsh-session), read by both write sites
(Session constructor default, SessionStore.prepare header) and the coordinator's
load-time assertVersion check. The constant is pinned at 0: while unreleased the
on-disk format is unstable/pre-release, so breaking shape churn is absorbed at v0
(no monotonic bump until the first tagged release) and any non-0 log is rejected
on load — no migration. Update every test/fixture/doc that stamps a
currently-written header to the constant, bump the ACP snapshot fixture + golden
headers to v0, and keep the version-rejection test meaningful by switching its
bad value to a clearly non-current 99. AGENTS.md documents both the monotonic
(SQLite SCHEMA_VERSION) and pinned-0 (session log) pre-release stances.
Blocker #2 — restore the late turn-end warn. failTurn now sets the error reason
only while the turn is still open; once turn/end is appended (a throwing
agent/turn-end listener after closeTurn) the reason can no longer reach the
durable log, so the late throw is logged via ctx.logger.warn instead of
vanishing into a futile post-close assignment. A regression test asserts the
warn fires.
Also guard the normal-step assistant/message append with the same
content-or-usage condition as the max-tokens branch (a content-less, usage-less
step records no trace-only row), with a covering test.
Yichen Jiang
Tianyi Cui
Hypatia May
imccyu