Postmortem writer

Skill willianbs/skills/postmortem-writer

Writes blameless postmortems from incident and RCA artifacts. Use after incidents resolve. Emits POSTMORTEM. Never blames individuals, never invents timeline facts, never skips action items with owners.From its SKILL.md

Install

npx -y skills add willianbs/skills --skill postmortem-writer

Assembled from the repository path, not quoted from the project. Check it against their README if it does not work.

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SKILL.md

2.7 KB, 571 tokens by cl100k_base, as published. Nobody here has run it

Purpose

Turn INCIDENT_LOG + RCA_REPORT into a clear, blameless learning document with accountable follow-ups.

When to Use / When NOT to Use

Use when: after SEV incidents; user asks for postmortem/PIR; defect-analyst completed rca mode.

Do not use when: active incident still unstable (incident-commander); speculative “what if” without an event.

Preconditions

Incident resolved or mitigated enough to write. Prefer INCIDENT_LOG + RCA_REPORT. If missing, interview for facts only.

Inputs / Outputs

Inputs: INCIDENT_LOG, RCA_REPORT/DEFECT_REPORT, OBS_PLAN gaps, IMPL_REPORT of fix optional.

Outputs: POSTMORTEM

Upstream / Downstream

Upstream: incident-commander, defect-analyst.

Downstream: delivery-planner (action items), observability-designer, adr-enforcer, engineering-mentor.

Core Principles

Blameless — systems and processes, not people.
Timeline from evidence only; mark Unknown.
Impact quantified when known (else Unknown).
Root cause + contributing factors + failed safeguards.
Action items: owner, due, severity; prevent recurrence.
What went well — keep it short and real.
Do not reopen the incident in prose; link facts.

Process

Ingest artifacts; list gaps to ask.
Draft: summary, impact, timeline, root cause, contributing factors, detection/response assessment.
Action items mapped to failed safeguards (pages, tests, runbooks, limits).
Severity/sev label from incident.
Review for blame language; rewrite.
Decision Proceed when actionable follow-ups exist.

Evidence Requirements

Every timeline entry needs source (log, INCIDENT_LOG, PR). No fiction.

Stop Conditions / Failure Modes

Condition	Action
Active SEV-1 still open	Defer to incident-commander
No action items	Revise — incomplete postmortem
Blame-centric draft	Rewrite before delivery

Severity + Confidence

Reflect incident sev; action items may be Critical if recurrence risk remains.

Output Contract

## POSTMORTEM
Summary: ...
Impact: ...
Timeline: ...
Root cause: ...
Contributing factors: ...
What went well: ...
Action items: owner, due, severity
Decision: Proceed | ProceedWithConditions | Revise | Block

Handoffs

delivery-planner, observability-designer, adr-enforcer, test-strategy-designer.

Never

Never name-and-shame.
Never invent customer impact numbers.
Never omit owners on action items.

What ships with it: 1 file

751 B alongside SKILL.md

README.md751 B