How do I install the Postmortem Writer skill?

Run npx skillmds@latest add willianbs/postmortem-writer in your terminal (requires Node.js), paste this page's agent-chat prompt into Claude, Cursor, or any MCP-connected agent, or download the SKILL.md file and copy it into your agent's skills directory.

Is Postmortem Writer safe to use?

This skill has not completed SkillMD's automated safety review yet. SkillMD never runs a skill's scripts for you; review the SKILL.md before installing.

Which AI agents work with Postmortem Writer?

This skill is tagged as working with Claude Code, Claude.ai, OpenAI Codex. SKILL.md is an open format, so most agents that read a skills directory can load it too.

Is Postmortem Writer free to use?

Yes. Installing skills from SkillMD is free, and the skill stays under its author's original license.

Who published Postmortem Writer?

willianbs (@willianbs) published this skill. Their other Agent Skills are listed on their SkillMD profile.

Postmortem Writer by willianbs — Agent Skill

Name: Postmortem Writer
Author: willianbs

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.

willianbs ccdf9eb 2 files · 3.4 KB Updated Sep 17, 2026

File contents

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.

---name: postmortem-writerdescription: 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.---# PurposeTurn 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.# PreconditionsIncident 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 Principles1. Blameless — systems and processes, not people.2. Timeline from evidence only; mark Unknown.3. Impact quantified when known (else Unknown).4. Root cause + contributing factors + failed safeguards.5. Action items: owner, due, severity; prevent recurrence.6. What went well — keep it short and real.7. Do not reopen the incident in prose; link facts.# Process1. Ingest artifacts; list gaps to ask.2. Draft: summary, impact, timeline, root cause, contributing factors, detection/response assessment.3. Action items mapped to failed safeguards (pages, tests, runbooks, limits).4. Severity/sev label from incident.5. Review for blame language; rewrite.6. Decision Proceed when actionable follow-ups exist.# Evidence RequirementsEvery 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 + ConfidenceReflect incident sev; action items may be Critical if recurrence risk remains.# Output Contract```## POSTMORTEMSummary: ...Impact: ...Timeline: ...Root cause: ...Contributing factors: ...What went well: ...Action items: owner, due, severityDecision: 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.

Frequently asked questions