pi-skills/.agents/skills/evolve/references/postmortem-checkpoint.md

Mandatory checkpoint: session-PR threshold (soc-n75z)

Stop reason #6 of /evolve. NOT terminal — gates the next cycle, not the loop's existence. Derivation: the 2026-05-19 and 2026-05-20 sessions both shipped 5-6 PRs while the agent self-graded "HEALTHY" without running a real council; STOP got written as if it were post-mortem completion. This procedure closes that gap.

When this fires

At Step 7 boundary, after a cycle whose result is improved or regressed ($session_pr_count is the canonical count from scripts/session-pr-scope.sh --count):

if [ "$session_pr_count" -ge "${SESSION_PR_THRESHOLD:-5}" ] \
   && [ "$session_pr_count_at_last_checkpoint" -lt "${SESSION_PR_THRESHOLD:-5}" ]; then
  # checkpoint fires once per crossing — not repeatedly at every cycle past 5
  run_postmortem_checkpoint
fi

The check is edge-triggered (fires when the counter first crosses the threshold), not level-triggered. After PASS/WARN, the loop continues until either another stop reason fires OR another threshold crossing — e.g., at 2 × SESSION_PR_THRESHOLD = 10, the checkpoint re-fires for a second post-mortem.

What it MUST do

1. Invoke /post-mortem --deep on the cycles since the last checkpoint (or session start). --deep runs 3 same-vendor judges in adversarial posture.

   • Do NOT use --mixed. Cross-vendor (Codex availability) is an infrastructure dependency that should not block the loop gate. Reserve --mixed for strategic architecture decisions (e.g., the DUEL.md precedent), not per-session health checks.
   • Do NOT use single-judge mode. Single-judge sweeps are too weak for a gate that enables continued autonomous work — the whole point of the checkpoint is adversarial counter-balance against the author who just wrote the cycles.

2. Wait for the verdict file at .agents/council/<date>-<scope>-postmortem/verdict.md. The verdict file's first non-blank line must start with ## Council Verdict: <PASS|WARN|FAIL>.

3. Branch on verdict:

   Verdict	Action
   PASS	Continue the ladder. Next cycle's notes field MUST record the verdict path.
   WARN	Continue the ladder. Next cycle's notes field MUST emit the council's caveats verbatim — they need to trace through cycle-history.jsonl so the loop's recorded behavior reflects what was acknowledged.
   FAIL	Write .agents/evolve/STOP with the verdict path embedded. Do NOT clear. Surface the council's required-follow-up list to the operator.

4. Treat non-convergence as FAIL. If after 600 seconds the verdict file is missing, malformed, or the council's judges disagreed irreconcilably after a second pass, default to FAIL. Absence of evidence is NOT evidence of pass. The 2026-05-20 failure mode was an empty 2-minute cron pass treated as council completion; this rule is the corrective.

What it MUST NOT do

• Never self-grade. The agent who ran the cycles is the same agent doing the post-mortem. Self-attestation is definitionally invalid for the gate; council enforcement is the structural requirement.
• Never write .agents/evolve/STOP without a council verdict file. STOP without a verdict is the 2026-05-20 anti-pattern — the file becomes a self-imposed pause that the same agent (or operator) clears without rigor. Every STOP written by this checkpoint must cite a verdict path that resolves to a FAIL verdict.
• Never run /post-mortem without --deep from this checkpoint. A light-touch cron-fire pass that writes learnings but skips Phase 1 council does not satisfy the gate. The 2026-05-20 cron /post-mortem was insufficient by design.

Pre-creation signal (opt-in, not shipped)

The pre-creation counterpart to this post-merge checkpoint — hooks/session-pr-counter.sh (PR #362, soc-1aou), which fired on gh pr create at count >= threshold - 1 — was removed in the 3.0 hookless teardown (#511). AgentOps ships no hook. The reusable session-PR count it provided now lives in scripts/session-pr-scope.sh (the canonical $session_pr_count source — scripts/session-pr-scope.sh --count). Re-author the always-on pre-creation signal as an opt-in hook via the hooks-authoring skill if you want it.

This checkpoint is the post-merge gate — it fires after PR #N+1 has merged, before cycle N+1 enters Step 1. It is mandatory and cannot be bypassed (the loop genuinely waits on the verdict file), unlike the advisory pre-creation signal:

Layer	Trigger	Default	Status
scripts/session-pr-scope.sh (wrap as an opt-in hook via hooks-authoring)	gh pr create at count >= threshold-1	Advisory	Reusable count; not shipped as a hook (removed in #511)
evolve checkpoint #6	Cycle boundary after count >= threshold	Mandatory	Structural council enforcement before the next cycle starts

Configuration

Variable	Default	Effect
SESSION_PR_THRESHOLD	5	Matches soc-waxr documentation default. The 2026-05-19 session (6 PRs, 3 self-corrections) and 2026-05-20 session (5 PRs, 1 self-correction + 1 confirmation-bias verdict) are the two derivation points. Do not change without a third data point.
EVOLVE_POSTMORTEM_TIMEOUT_SEC	600	Max wait for verdict file. Past this, treat as FAIL.
EVOLVE_POSTMORTEM_COUNCIL_FLAG	--deep	Override only with operator sign-off in a follow-up PR; reverting to single-judge or --mixed requires a council justifying the change.

Failure modes this closes

The 2026-05-20 post-mortem (.agents/council/2026-05-20-evolve-204-208-postmortem/verdict.md) found WARN with Q4 FAIL:

The "post-mortem" that "cleared" cycle 208 was a cron-fire that wrote 5 learning files and appended a harvest entry. No Phase 1 (council) ran. No Phase 2 extraction with adversarial review. No Phase 3 backlog processing. No verdict file was produced.

Cycle 208's notes contain the string "HEALTHY verdict from /post-mortem cron" — a verdict that does not exist in any file the council directory contains.

That cycle-history entry transformed an absence (no council ran) into a positive claim (clearance exists) in an append-only ledger. Stop reason #6 prevents that pattern by requiring a real verdict file path before continuing.

Cross-references

• skills/post-mortem/SKILL.md — the post-mortem skill this checkpoint invokes
• skills/council/SKILL.md — the council skill --deep runs against
• skills/ship-loop/SKILL.md — the soc-waxr session-scope doctrine source
• scripts/session-pr-scope.sh — canonical session-PR count source (the pre-creation hook was removed in #511; re-author as an opt-in hook via hooks-authoring)
• CLAUDE.md § "Autonomous-session scope" — top-level doctrine reference
• .agents/council/2026-05-20-evolve-204-208-postmortem/verdict.md — the derivation council (local; gitignored)