ARC Skills
Operationsintermediateupdated 2026-08-11v1.0

Postmortem Writer

Turn an incident timeline and notes into a blameless postmortem with impact, contributing factors, and numbered follow-ups. Use after an incident when writing a PIR, RCA, or postmortem doc.

#postmortem#incident#sre#rca
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Install this skill

Copy the file into your agent runtime. Cursor loads personal skills from ~/.cursor/skills/postmortem-writer/SKILL.md and project skills from .cursor/skills/postmortem-writer/SKILL.md. Claude Code looks in .claude/skills/postmortem-writer/SKILL.md.

Postmortem Writer

When to use

The incident is mitigated and the team needs a written record. Triggers: write the postmortem, draft the PIR, root cause analysis.

What it does

Produces a blameless postmortem: summary, customer/user impact, timeline (or pointer to one), contributing factors, what went well, what to change, and numbered actions with owners.

Steps

  1. Write a 5-line summary a non-engineer can read.
  2. Quantify impact: users, duration, revenue/SLA if known. Mark unknown as unknown.
  3. Paste or summarize the timeline. Do not rewrite timestamps.
  4. Separate trigger (what started it) from contributing factors (why it spread). Avoid a single "root cause" if several factors stacked.
  5. List follow-ups as owner / due / success criterion. Prefer unassigned over inventing a person.

Output

# Postmortem — <title> — <date> with sections: Summary, Impact, Timeline, Contributing factors, What went well, Follow-ups.

Guardrails

No blame language ("X should have known"). Do not invent metrics. If a follow-up has no owner, mark unassigned rather than guessing. Do not declare "this can never happen again."