The dangling-event repair kept only the FIRST "started" entry per
skill+session key and treated "completed" as a set, so any key where one
run completed and another dangles was never repaired — and keys are not
unique per run: legacy entries with no session field all share the
bare-skill key, and the preamble's "$$-epoch" session ids collide within
the same second. One old completion masked every future dangler forever.
The hook now counts started vs completed per key and appends completions
for the DIFFERENCE. Idempotency holds by construction: the appended
completions balance the counts, so the next Stop appends nothing. Pinned
with the two-runs-one-dangling case plus a re-run no-op assertion; all
existing fail-open cases pass unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The Stop hook runs on EVERY Claude Code turn machine-wide and re-read +
JSON-parsed the entire timeline each time, scaling to the 10MB size cap
(~100-300ms per turn of pure overhead). It now reads only the last 256KB
via fstat + positioned read, discarding the first partial line when the
window starts mid-file.
Semantics: a dangling "started" older than the last 256KB of appends
belongs to a session long gone — beyond repair interest. The window can
never fabricate a dangling entry ("completed" is always appended AFTER its
"started", so any started inside the window has its completion inside the
window too), so idempotency holds. The fail-open contract is unchanged:
exit 0 always, size cap kept, deadline re-checked before the write.
New test: a >256KB timeline where a recent dangling entry still gets
repaired while an old out-of-window dangler is left alone; all existing
fail-open cases pass unchanged.
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
The preamble writes event:'started' to the project timeline at every skill
start, but the matching 'completed' write lives in prose at the END of the
skill workflow — unenforceable. An interrupted session, a context blowout,
or an agent that simply stops leaked started > completed forever, and the
leak was unrepairable after the fact (observed live in #2553).
New hosts/claude/hooks/timeline-stop-hook (+ .ts, question-log-hook shim
pattern): on Claude Code's Stop event it appends event:'completed' with
outcome 'unknown' and source 'stop-hook' for every 'started' entry in the
project timeline that has no matching completion. setup registers it via
gstack-settings-hook add-event (Stop was already an accepted event) under
its own source tag, idempotently; --no-team and gstack-uninstall remove it.
FAIL-OPEN contract (F5), pinned by tests: ALWAYS exits 0 — corrupt
timeline (bad lines skipped individually, valid ones still repaired),
missing timeline, garbage/empty stdin, bun missing from PATH (the shim
'|| true's), and an over-cap timeline (10MB skip) all repair nothing and
block nothing; errors land in ~/.gstack/hook-errors.log best-effort. The
write path is append-only with a ~2s internal budget, and a second Stop is
a no-op (already-closed entries never re-close). Correlation is
project-scoped by design — the preamble's session id is shell-local, so a
concurrent same-project session's entry may close early as a traceable
source:'stop-hook' row rather than a silent leak; the header documents the
trade-off.
Fixes#2553
Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>
