v0.40.0: capture task telemetry via SubagentStop (confirmed root cause)#38
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Resolves the multi-release "0 task events" mystery with a clean,
in-session empirical proof — not another guess.
The proof (run this session, fresh 0.39.3, async already reverted):
1. Captured a cutoff timestamp.
2. Dispatched a real subagent via the Agent tool (32947 tokens,
returned). Result: ZERO events after cutoff.
3. In the SAME session, triggered a Read-deny on a large file.
Result: exactly 1 `denied` event written after its cutoff.
4. An unbounded recursive search was blocked by hook-pre-bash
(hooks demonstrably live this session).
So: appendEvent + the hook runtime are healthy (Read-deny wrote),
but PostToolUse:Task produces nothing on a real dispatch. That is
the entire "0 task events" history explained — the parent-side
PostToolUse hook simply does not fire for the dispatch tool on this
Claude Code. async (v0.35.0) was never the cause; the April zeros
predate it. Releases v0.33.1 / v0.39.2 chased the wrong layer.
The fix — SubagentStop:
Claude Code's SubagentStop is the canonical subagent-completion
event (bundle schema: agent_id, agent_type, agent_transcript_path,
last_assistant_message). It fires once per subagent by definition.
New hook-subagent-stop writes the `event:"task"` record from it:
- subagent_type = agent_type (the adoption signal v0.30 needs:
was a subagent used, tp-* or not)
- estTokens = best-effort sum from the transcript usage
(agent_transcript_path), 0 on any failure
- code:"subagent_stop" marks the source so a future revival of
PostToolUse:Task can be deduped, not double-counted
Routing-miss detection (general-purpose where tp-* fit) stays in
the PreToolUse:Task diagnostic, which has the task description
SubagentStop lacks.
Wiring:
- src/hooks/subagent-stop.ts — buildSubagentTaskEvent +
tokensFromTranscript (both pure / injectable, fully tested).
- index.ts case hook-subagent-stop (synchronous — writes telemetry).
- hooks/hooks.json + installer.ts: SubagentStop section, installed
+ uninstalled idempotently alongside the others.
- typo-guard registers hook-subagent-stop.
Verified end-to-end against the built dist: a SubagentStop payload
for tp-pr-reviewer writes event:"task" subagent_type=tp-pr-reviewer
code=subagent_stop.
PostToolUse:Task is KEPT (harmless; carries tokens if CC ever fixes
it; code-marked events let stats dedup).
Tests: 1328/1328 pass (+9 subagent-stop + typo-guard).
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Resolves the multi-release "0 task events" mystery with a clean in-session proof.
Proof (fresh 0.39.3 session, async already reverted)
deniedevent written.hook-pre-bashblocked an unbounded search → hooks demonstrably live.So appendEvent + runtime are healthy (Read-deny wrote), but PostToolUse:Task produces nothing on a real dispatch — the entire "0 task events" history explained. async was never the cause (April zeros predate it); v0.33.1 / v0.39.2 chased the wrong layer.
Fix — SubagentStop
CC's canonical subagent-completion event (fires once per subagent). New
hook-subagent-stopwrites theevent:"task"record:subagent_type = agent_type(the adoption signal v0.30 needs)estTokens= best-effort transcript usage sum (0 on failure)code:"subagent_stop"source marker for future dedupRouting-miss detection stays in the PreToolUse:Task diagnostic (it has the description). PostToolUse:Task kept (harmless, carries tokens if CC fixes it).
Wiring
src/hooks/subagent-stop.ts(pure, tested) ·index.js hook-subagent-stop(sync) · hooks.json + installer SubagentStop section (install + uninstall idempotent) · typo-guard.Verified e2e against dist. 1328/1328 tests (+9).