Codex review of the draft: the abort-on-dispose tests asserted only that
dispose() resolved and no warning fired — a regression back to untracked
fire-and-forget runs would pass both. The hook script now records its
shell PID before sleeping, and after dispose the test asserts
process.kill(pid, 0) throws: the drain resolves only after the killed
run settled (the child reaped), so ESRCH-by-dispose-return is
deterministic under the correct implementation, while an alive or
unreaped process fails it. Verified the discriminator by gutting drain()
locally: exactly these two tests fail.
The emit-shaped hook points (SessionStart, SubagentStart, SubagentStop)
run fire-and-forget: no seam awaits the run chain, so disposing a bridge
could strand a live hook process and let a late continuation inject into
a disposed context. The floating continuation also made the coverage
gate racy: the only coverage of the SubagentStart continuation's
no-context branch arm rode on an un-awaited .then, and on a loaded CI
runner the fork's per-file coverage snapshot beat it — master run
28798191671 failed the 100% branch gate on hooks-claude/src/index.ts at
99.03% (uncovered line 336) with the identical tree passing the PR run
three minutes earlier.
New shared primitive createDetachedRuns() in dsh-hook-protocol: a bridge
tracks each detached run chain, passes the tracker's abort signal to
runHook, and registers drain() as its effect disposer — drain aborts
still-running hook processes (a kill via the bash seam, not a wait out
to the 10-minute default hook timeout), then resolves once every chain
has settled. fiber.dispose() resolving now means the bridge's detached
work is quiescent (docs/defensive-patterns.md).
The subagent marker test disposes the bridge as its sync point, so the
formerly racy branch arm is executed deterministically before the file's
coverage snapshot; new tests pin abort-on-dispose promptness for both
bridges and the tracker's settle/drain contract in hook-protocol.
Round-2 Codex review of the round-1 fixes:
- (A) The Codex plain-stdout→additionalContext fold (F1) was not gated on exit
code, so a NON-clean hook's stdout still injected: a SessionStart `echo stale;
exit 2` (an emit — cannot block) wrongly injected "stale", and a
UserPromptSubmit `exit 1` (non-blocking error → falls through to context) did
too. Gate the fold on `output.exitCode === 0`, matching the codec's own
structured-stdout rule. Guard tests for both paths, proven red without the gate.
- (B) The Codex "SessionStart no-context no-op" absence test was unsound (a
completed turn doesn't prove the detached hook finished). It now touches a
marker and waitFor()s it before asserting no context.
- (B) Both HMR tests used a no-op `true` hook, so a leaked listener would still
pass. They now use a BLOCKING (exit 2) UserPromptSubmit hook and assert the
post-dispose turn is NOT blocked and logs no hook/invoked — a leaked listener
fails loudly.
The two bridge plugins that run a user's existing Claude Code / Codex hook
config on the harness's typed interception seams, built on the shared
dsh-hook-protocol library. A bridge is a faithfulness adapter, not a power
tool: anything it does a native cordis plugin does more powerfully — the
bridge exists only to run UNMODIFIED external hooks.
- dsh-hooks-claude: CC dialect. Seven hook points (SessionStart,
UserPromptSubmit, PreToolUse, PostToolUse, Stop, SubagentStart,
SubagentStop), CC per-event stdin payloads, env + ${CLAUDE_PLUGIN_ROOT}/
${CLAUDE_PROJECT_DIR} substitution, literal-or-regex matcher.
- dsh-hooks-codex: Codex dialect — a deliberate subset. Five hook points,
always-regex matcher, snake_case payloads (turn_id/model, no trailing
newline), no env/substitution, block-only decisions.
Both map the neutral merged outcome onto the seam's typed Decision and stamp
an explicit {kind:'plugin'} source on injected context (so it is never
mislabeled as a user prompt). Config parse-failure is contained; only command
hooks run. updatedInput is logged+warned (input rewrite deferred); the Stop
loop-guard is deferred (TODO).
Tests: per-file 100% — config-parse unit branches + per-seam mappings
end-to-end through the REAL loop + REAL bash + REAL shell scripts (scripted
mock model only) + a real-Loader export-shape guard. A keyless ACP snapshot
scenario (hook-prompt-block) proves a UserPromptSubmit hook blocks a prompt
end-to-end (rejected turn -> ACP cancelled, hook/* events in the log); a
with-key e2e (hooks.e2e.ts) proves a PreToolUse hook blocks real bash
(verified on disk). The snapshot normalizer now scrubs hook/result.durationMs.
RFC: docs/rfc/implemented/feature/2026-06-30-hook-bridges.md
Turtle
Tianyi Cui
Yichen Jiang