postmortem

A structured incident review that records what happened, when it happened, its effects, and what should change afterward. It is blameless, meaning it focuses on systems and processes instead of blaming individuals.

In plain words
What is it for?
Use it after an outage, security event, or failed project to document the timeline, impact, causes, response, and prevention tasks.
Why use it?
It turns outages, security incidents, and project failures into lessons that can reduce repeat problems. A shared timeline and clear actions make follow-up easier.

Skill for Claude CodeCodex

Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

agentmods
npx agentmods add skills/neurofoo/agent-skills/postmortem
Any agent
npx skills add neurofoo/agent-skills --skill postmortem
Clone the repo
git clone --depth 1 https://github.com/neurofoo/agent-skills

Made for: Claude Code, Codex.

Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 689 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. Scan, not verified.
Origin original No closer match found in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5 $0.00042 $0.00689
Opus 5 $0.00021 $0.00345
Sonnet 5 $0.00008 $0.00138
Haiku 4.5 $0.00004 $0.00069

Measured 3d ago against content hash a4e8d0d594e3, method: parsed. Prices are Anthropic first-party input rates as of 2026-08-30, from the pricing page.

Security

Grade A, and why

postmortem scanned grade A with 0 findings against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 3d ago.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Nothing flagged

None of the 26 patterns this scan looks for appear in this file: no shell pipes, no recursive deletes, no credential paths, no hidden text, no instruction-override or anti-refusal phrasing, no agent-config snooping. That is not a guarantee, it is the absence of the things that are checkable.

postmortem/SKILL.md · 126 lines

How it starts

The opening of the file, as written. The whole thing — 126 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Blameless Post-Mortem

Conduct a thorough, blameless analysis of an incident to understand what happened and prevent recurrence.

Instructions

Work through each section systematically. Focus on systems and processes, not individuals. The goal is learning, not blame.

Output Format

Executive Summary

Incident: [One-line description] Date/Time: [When it occurred] Duration: [How long] Severity: [Critical/High/Medium/Low]

Summary [2-3 sentence overview: what happened, impact, resolution]


Timeline

All times in [timezone].

Time Event Actor
HH:MM [What happened] [Who/what did it]
HH:MM [Detection] [How it was noticed]
HH:MM [Response action] [Who responded]
HH:MM [Resolution] [What fixed it]

Key Moments

  • Trigger: [What initiated the incident]
  • Detection: [How/when we knew something was wrong]
  • Mitigation: [When bleeding was stopped]
  • Resolution: [When fully resolved]

Impact

Customer Impact

  • Users affected: [number]
  • Duration of impact: [time]
  • Symptoms experienced: [what users saw]

Business Impact

  • Revenue impact: [if applicable]
  • SLA/SLO breach: [yes/no, details]

Root Cause Analysis

Root Cause [The fundamental reason this happened—not the trigger, but why the trigger caused an incident]

Trigger [The immediate cause—what set things in motion]

Contributing Factors

Factor How It Contributed
[factor] [explanation]

Why Wasn't This Caught?

  • Why didn't tests catch it?
  • Why didn't monitoring alert earlier?

What Went Well

What Worked Why It Helped
[thing] [explanation]

What Went Poorly

What Failed Impact
[thing] [impact]

Action Items

Immediate (This week)

Action Owner Due
[action] [owner] [date]

Short-term (This month)

Action Owner Due
[action] [owner] [date]

Read the full file on GitHub · 126 lines

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 3d ago First seen · 126 lines · 42 tokens per session scan A a4e8d0d594e3

Subscribe to this mod's changes

postmortem is a skill published in the GitHub repository neurofoo/agent-skills (111 stars, last pushed 7mo ago), licensed MIT. It adds 42 tokens to every session and 689 once invoked, about $0.0002 per session on Opus 5. A static security scan graded it A with 0 findings. No closer match exists in the catalogue, so it is treated as the original; first seen 2026-08-30.

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