postmortem

postmortem is a skill for Claude Code, Codex from nicepkg/ai-workflow. It costs 80 tokens per session (3,212 once invoked), scanned A, original, MIT.

A guide to reviewing failures, outages, incidents, and missed outcomes without blaming individuals. It documents what happened, finds underlying causes, and records actions to prevent a repeat.

In plain words
What is it for?
Use it after outages, security incidents, data loss, failed launches, missed deadlines, quality problems, or serious near misses.
Why use it?
It helps teams learn from problems instead of fixing only their visible symptoms. A structured review makes impact, causes, ownership, and prevention steps easier to track.

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

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 postmortem

README.md
[![agentmods](https://agentmods.dev/badge/skills/nicepkg/ai-workflow/postmortem.svg)](https://agentmods.dev/skills/nicepkg/ai-workflow/postmortem)
Your own site
<a href="https://agentmods.dev/skills/nicepkg/ai-workflow/postmortem"><img src="https://agentmods.dev/badge/skills/nicepkg/ai-workflow/postmortem.svg" alt="Measured on agentmods" height="20"></a>
Per session 80 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 3,212 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 $0.00080 $0.03212
Opus 5 $0.00040 $0.01606
Sonnet 5 $0.00016 $0.00642
Haiku 4.5 $0.00008 $0.00321

Measured yesterday against content hash 81bbaa16ade4, 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 yesterday.

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.

workflows/product-manager-workflow/.claude/skills/postmortem/SKILL.md · 277 lines

How it starts

The opening of the file, as written. The whole thing — 277 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Postmortem

Table of Contents

  1. Purpose
  2. When to Use
  3. What Is It?
  4. Workflow
  5. Common Patterns
  6. Guardrails
  7. Quick Reference

Purpose

Conduct blameless postmortems that transform failures into learning opportunities by documenting what happened, why it happened, impact quantification, root cause analysis, and actionable preventions with clear ownership.

When to Use

Use this skill when:

Incident Context

  • Production outage, system failure, or service degradation occurred
  • Security breach, data loss, or compliance violation happened
  • Product launch failed, project missed deadline, or initiative underperformed
  • Customer-impacting bug, quality issue, or support crisis arose
  • Near-miss incident that could have caused serious harm (proactive postmortem)

Learning Goals

  • Need to understand root cause (not just symptoms) to prevent recurrence
  • Want to identify systemic issues vs. individual mistakes
  • Must document timeline and impact for stakeholders or auditors
  • Aim to improve processes, systems, or practices based on failure insights
  • Building organizational learning culture (celebrate transparency, not blame)

Timing

  • Immediately after incident resolution (while memory fresh, within 48 hours)
  • Scheduled reviews for recurring issues or chronic problems
  • Quarterly reviews of all incidents to identify patterns
  • Pre-mortem style: Before major launch, imagine it failed and write postmortem

Do NOT use when:

  • Incident still ongoing (focus on resolution first, postmortem second)
  • Looking to assign blame or punish individuals (antithesis of blameless culture)
  • Issue is trivial with no learning value (reserved for significant incidents)

What Is It?

Postmortem is a structured, blameless analysis of failures that answers:

  • What happened? Timeline of events from detection to resolution
  • What was the impact? Quantified harm (users affected, revenue lost, duration)
  • Why did it happen? Root cause analysis using 5 Whys, fishbone, or fault trees
  • How do we prevent recurrence? Actionable items with owners and deadlines
  • What went well? Positive aspects of incident response

Read the full file on GitHub · 277 lines

Files

What ships with it

3 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

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. yesterday First seen · 277 lines · 80 tokens per session scan A 81bbaa16ade4

Subscribe to this mod's changes

postmortem is a skill published in the GitHub repository nicepkg/ai-workflow (283 stars, last pushed 7mo ago), licensed MIT. It adds 80 tokens to every session and 3,212 once invoked, about $0.0004 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 2026-09-03.