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.
Codex review of the interception-seams merge flagged current-state prose still
describing removed/renamed surfaces:
- packages/core/agent/src/types.ts module doc: the agent/* "transient emits"
list still ended with "the turn boundaries" — corrected to state turn/step
boundaries are durable session/event records, not agent/* emits, and to list
the actual interception seams (prompt-submit/pre-step/request/step-result/
turn-continuation) + agent/session-start.
- interception-seams RFC: "agent/turn-end fires and the ACP bridge settles" →
the durable turn/end is appended and ACP settles off it (no turn mirror).
- two proposed RFCs (acp-agent-client-protocol, optional-code-mode) named the
pre-split `tools/execute` waterfall → the `tools/pre-execute`/`tools/post-execute`
pair.
Regenerated the cordis catalog (module-doc change). No code/behavior change.
- core-data-structures/core.md: the `agent/*` taxonomy said "turn/step
boundaries", but the step-boundary mirror emits were dropped — `agent/*`
mirrors only turn boundaries; step boundaries are durable `step/start`/
`step/end` session events. Narrow the catalog so plugin authors aren't pointed
at nonexistent `agent/*` step events.
- interception-seams RFC: replace stack-position phrasing ("a later stack PR",
"the stack's first change", "the PR that makes...") with durable mechanism/RFC
names (the hook bridge packages, the event-domain-semantics RFC).
- tools/post-execute snapshot: `dispatched.content` was the same array reference
as `result.content`, so a listener's in-place `push`/`splice` leaked into the
returned content while a reassignment was masked — the "protect from tampering"
comment over-claimed. Copy content into a fresh array so the snapshot guards
the array structure; comment now states it is not deep immutability. Regression
extended to push a block in-place and assert it does not leak (proven red
without the copy).
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).
