---
name: ai-postmortem
description: Documents production incidents, outages, degradations, and near-misses using the DERP format (Detection, Escalation, Recovery, Prevention) with targeted interview questions per phase. Trigger for 'we had an incident', 'write up the outage', 'something went wrong in prod', 'postmortem', 'near-miss analysis', 'incident report'. Not for customer support investigations; use /ai-support instead. Not for internal dev bugs; use /ai-debug instead.
effort: mid
argument-hint: "start|continue [id]|find [query]|generate"
model_tier: sonnet
mirror_family: codex-skills
generated_by: ai-eng sync
canonical_source: .claude/skills/ai-postmortem/SKILL.md
edit_policy: generated-do-not-edit
---



# Postmortem

## Purpose

Structured incident postmortem using the DERP model. Guides through Detection, Escalation, Recovery, and Prevention phases with targeted questions. Produces blameless, actionable postmortem documents.

## Trigger

- Command: `/ai-postmortem start|continue|find|generate`
- Context: incident occurred, production failure, outage resolution, near-miss analysis.

## Workflow

Four modes follow the DERP loop:

1. `start` — scaffold a new postmortem under `.ai-engineering/postmortems/PM-YYYY-NNN.md` from the template; pose Detection-phase questions.
2. `continue <id>` — resume an in-progress postmortem; advance through Escalation → Recovery → Prevention.
3. `generate` — synthesize from existing session context (recent commits, alerts, logs).
4. `find [query]` — search past postmortems for similar patterns.

## Modes

### start -- New postmortem

1. **Assign ID** -- generate `PM-YYYY-NNN` (sequential within year).
2. **Set status** -- `draft`.
3. **Scaffold** -- create `.ai-engineering/postmortems/{id}.md` with DERP template.
4. **Interview -- Detection**:
   - When was the incident first detected?
   - How was it detected? (monitoring, user report, manual discovery)
   - What was the time between incident start and detection?
   - What monitoring should have caught it earlier?
5. **Interview -- Escalation**:
   - Who was notified and when?
   - Was the escalation path appropriate?
   - Were the right people involved at the right time?
6. **Interview -- Recovery**:
   - What actions were taken to restore service?
   - What was the total downtime/impact duration?
   - Was there a rollback? What was the rollback procedure?
7. **Interview -- Prevention**:
   - Root cause (use 5-Whys if needed)
   - What changes prevent recurrence?
   - Action items with owners and deadlines

Ask ONE section at a time. Wait for answers before proceeding to the next DERP phase. If the user provides answers for multiple DERP phases at once (e.g., pastes an incident timeline), extract the relevant information into each section rather than re-asking. Only interview for sections that remain incomplete.

### continue <id> -- Resume postmortem

1. **Load** -- read `.ai-engineering/postmortems/{id}.md`.
2. **Find gap** -- identify the first incomplete DERP section.
3. **Resume interview** -- continue from the incomplete section.

### find [query] -- Search postmortems

1. **Search** -- scan `.ai-engineering/postmortems/*.md` for matching content.
2. **List** -- show ID, title, date, status, and root cause summary.

### generate -- Create from existing notes

1. **Collect** -- gather incident-related commits, PRs, Slack threads (if provided by the user as pasted text), and notes from context.
2. **Draft** -- populate DERP sections from available data, mark gaps as `[NEEDS INPUT]`.
3. **Review** -- present draft for user validation before saving.

## Document Template

```markdown
# {id}: {title}

**Date**: YYYY-MM-DD
**Status**: draft | in-review | complete
**Severity**: SEV-1 | SEV-2 | SEV-3
**Duration**: {total impact time}

## Detection
{How and when the incident was discovered}

## Escalation
{Notification chain and response timeline}

## Recovery
{Steps taken to restore service}

## Prevention
### Root Cause
{5-Whys analysis}

### Action Items
| # | Action | Owner | Deadline | Status |
|---|--------|-------|----------|--------|

## Timeline
| Time | Event |
|------|-------|
```

## Status Progression

`draft` -> `in-review` (all DERP sections complete) -> `complete` (action items assigned)

## Quick Reference

```
/ai-postmortem start                  # begin new postmortem
/ai-postmortem continue PM-2026-001   # resume in-progress postmortem
/ai-postmortem find database           # search past postmortems
/ai-postmortem generate               # generate from existing context
```

Storage: `.ai-engineering/postmortems/{id}.md` (ID format `PM-YYYY-NNN`).

## Examples

### Example 1 — start a new postmortem after an outage

User: "we had an outage in checkout this morning, write it up"

```
/ai-postmortem start
```

Scaffolds `PM-2026-001.md`, asks Detection-phase interview questions (when/how detected, time-to-page, alert quality), advances to Escalation when answered.

### Example 2 — generate from session context

User: "synthesize a near-miss postmortem from this debug session"

```
/ai-postmortem generate
```

Reads recent debug session, alerts, commits; drafts DERP sections with TBD markers where data is incomplete.

## Integration

Called by: user directly. Reads: alerts, runbooks, `/ai-debug` outputs, recent commits. Writes: `.ai-engineering/postmortems/PM-YYYY-NNN.md`. See also: `/ai-debug` (root cause), `/ai-support` (customer-facing), `/ai-learn` (post-incident lessons).

$ARGUMENTS
