# Postmortem

> Test an explicit retrospective causal question against evidence and counterfactuals after Validate and Learn. Triggers: "postmortem", "causal retrospective", "test a retrospective hypothesis".

- Skill: `majiayu000/postmortem-5` (Agent Skill, multi-file: 2 files)
- Install (CLI): `npx skillmds@latest add majiayu000/postmortem-5`
- Raw SKILL.md: https://api.skillmd.com/api/skills/majiayu000/postmortem-5/raw
- Safety review: pending (external: skill-scanner PASS, skillspector PASS)
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: majiayu000 (https://skillmd.com/u/majiayu000)
- Updated: 2026-09-22
- Page: https://skillmd.com/skills/majiayu000/postmortem-5

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# Postmortem

> **Purpose:** Answer an explicit retrospective causal question using the
> already-validated outcome and evidence.

## Critical Constraints

- Because proof and causal inference are different judgments, Postmortem is retrospective causal analysis, not the general learning umbrella and not a completion gate.
- It consumes an immutable Validate verdict plus Learn receipt and does not re-run acceptance validation by default because Validate already owns that proof.
- Treat causal statements as hypotheses because causal confidence must survive
  alternatives. Separate observed sequence, contributing conditions,
  counterfactuals, and unknowns.
- A correlation is not promoted to cause without evidence that discriminates
  plausible alternatives.
- Because the caller owns delivery decisions, do not rewrite proof, operate
  tracker state, change the remaining plan, or promote a rule. Return evidence
  to the caller.
- Empty or inconclusive analysis is valid; manufacture neither certainty nor a
  lesson to make the retrospective feel useful.

## Workflow

1. Pin the verdict, Learn receipt, delivered artifact, and explicit causal
   question.
2. Reconstruct the evidence-backed timeline without importing hidden author
   reasoning as fact.
3. List candidate contributing conditions and at least one plausible
   alternative explanation.
4. Test each claim against cited evidence and a counterfactual: what should
   differ if the claim were false?
5. Optionally use independent judges to challenge contested causal claims.
6. Emit a report containing supported claims, rejected claims, unknowns,
   evidence references, and suggested experiments. Stop.

## Output Specification

- **Artifact directory:** `.agents/council/`.
- **Filename convention:** `YYYY-MM-DD-postmortem-<topic>.md`.
- **Serialization/schema format:** Markdown with causal question, pinned inputs,
  timeline, hypotheses, evidence, counterfactuals, unknowns, and experiments.
- **Validator command:** `bash skills/postmortem/scripts/validate.sh`.
- **Downstream handoff:** Learn or the orchestrator may consume the analysis; they own
  any bookkeeping, promotion, planning, or delivery decision.

## Quality Checklist

- [ ] The causal question and immutable inputs are pinned.
- [ ] Supported and rejected claims cite discriminating evidence.
- [ ] Alternatives, counterfactuals, and unknowns remain visible.
- [ ] The report stops short of proof, planning, tracker, and delivery authority.

Executable behavior is in [postmortem.feature](references/postmortem.feature).