incident-postmortem

incident-postmortem is a skill for Claude Code, Codex from jnMetaCode/skillet. It costs 42 tokens per session (544 once invoked), scanned A, original, MIT.

A guide for writing an incident postmortem, a factual record of an outage or other serious failure. It focuses on timelines, user impact, causes, and actions that improve the system without blaming individuals.

In plain words
What is it for?
Use it after an outage or incident to document detection, diagnosis, mitigation, resolution, impact, causal chains, and follow-up actions.
Why use it?
It turns logs, alerts, deployments, and other evidence into a useful account of what happened. This helps teams fix underlying system weaknesses and learn from the incident.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one.

Good fit Use it after an outage or incident to document detection, diagnosis, mitigation…

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/jnmetacode/skillet/incident-postmortem
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.

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

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for incident-postmortem

README.md
[![agentmods](https://agentmods.dev/badge/skills/jnmetacode/skillet/incident-postmortem.svg)](https://agentmods.dev/skills/jnmetacode/skillet/incident-postmortem)
Your own site
<a href="https://agentmods.dev/skills/jnmetacode/skillet/incident-postmortem"><img src="https://agentmods.dev/badge/skills/jnmetacode/skillet/incident-postmortem.svg" alt="Measured on agentmods" height="20"></a>
Per session 42 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 544 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 0 findings. A grade says what 26 rules found in the file — not that it is safe.
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 5.1 $0.00042 $0.00544
Opus 5 $0.00021 $0.00272
Sonnet 5 $0.00008 $0.00109
Haiku 4.5 $0.00004 $0.00054

Measured 6d ago against content hash 0fccd76ab00b, method: parsed. Prices are Anthropic first-party input rates as of 2026-09-06, from the pricing page.

Security

Grade A, and why

incident-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 6d 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.

skills/incident-postmortem/SKILL.md · 49 lines

What it actually says

incident-postmortem

A postmortem exists to change the system, not to assign blame or to perform remorse. Optimize for the engineer two years from now who hits something similar at 3am.

Procedure

  1. Timeline first, from artifacts. Build it from logs, alerts, deploy records and chat timestamps — not memory. Every entry: time (with zone), what happened, what was known at that moment. Mark detection, diagnosis, mitigation, resolution.
  2. Impact, quantified. Who/what/how long/how many: "checkout failed for 12 customers over 3h; all recovered" beats "some users were affected".
  3. Root cause as a causal chain, not a single line. Use "because" links: webhooks dropped → because the endpoint 500'd on duplicates → because a unique-constraint violation was treated as fatal → because the handler assumed Stripe never retries. The last "because" is usually an assumption, and assumptions are what you fix.
  4. Blameless mechanically: name systems and decisions, not people. "The deploy script allowed a config-less rollout" — not "X forgot the config". If a person had to be careful for the system to be safe, that's the finding.
  5. What went well / what got lucky. Luck is a finding too ("we noticed only because someone happened to be watching dashboards").
  6. Action items that would have prevented or shortened THIS incident, each with an owner and a date. Test each one: "would this have helped on the timeline above?" If not, cut it. 3–5 strong items beat 15 aspirational ones.

Skeleton

# 2026-04-02 — Payments webhook outage (3h, 12 failed checkouts)

**Summary** (3 sentences: what broke, impact, fix)
**Timeline** (timestamped, detection → resolution)
**Root cause** (causal chain, ending at the broken assumption)
**What went well / what got lucky**
**Action items** (owner · due date · "would it have helped?")
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. 6d ago First seen · 49 lines · 42 tokens per session scan A 0fccd76ab00b

Subscribe to this mod's changes

incident-postmortem is a skill published in the GitHub repository jnMetaCode/skillet (1 stars, last pushed 2mo ago), licensed MIT. It adds 42 tokens to every session and 544 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 2026-08-31.

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