Tier-2 reaped a LIVE, still-finalizing monitor: _monitor_agent writes
agent_runs.exit_code FIRST, then does git push / PR / Plane comments before
_finalize_job, and the agent pid is already dead in that window — so the old
"exit_code recorded -> reap now" had no grace and could race a healthy job.
Worse, _reap_known_outcome ran the advance (advance_stage -> enqueue_job)
BEFORE the atomic claim, so a reaper that lost the race had already enqueued
the next stage (dup advance / dup enqueue), violating ADR-001 Р-1.
Fix:
- Tier-2 grace: reap only once agent_runs.exit_code has been recorded for
>= reaper_finalize_grace_s (new setting, default 300s; > max finalization
window). A live finalizing monitor is never reaped (FR-1.3/AC-3). New
finished_age_s column computed in get_running_jobs.
- claim-before-act for exit0: evaluate the canonical QG READ-ONLY (the
reconciler pattern) to choose the terminal status, then atomically claim
'done' FIRST; only the claim winner runs the advance. A loser performs no
side effects -> no dup advance / dup enqueue.
Docs (golden source) updated in the same change: ADR-001, global adr-0011,
README, internals, .env.example, CHANGELOG (also fixes the P3 broken adr-0011
link). New tests cover the grace window, lost-claim no-side-effects, and the
already-advanced idempotent path.
Refs: ORCH-065
Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>
