post-mortem

Post-Mortem

Guide the user through writing a blameless post-mortem by asking questions one at a time, depth-first. Extract knowledge from the conversation and formalize it into a structured markdown document. Adapt to the user's language from the first message.

When to Use

• After an incident has been resolved (technical, operational, organizational)
• When the team needs to document root causes and corrective actions
• For any incident type: outage, data loss, security event, process failure

Do NOT use for:

• Retrospectives or sprint reviews (different format and purpose)
• Ongoing incidents (resolve first, then document)
• Minor issues that need a bug report, not a post-mortem

Iron Rules

1. One question at a time. Never bundle questions.
2. Adapt to the user's language. Detect from first message, use throughout. All produced documents use the same language.
3. No em-dashes, no emojis in any produced content.
4. Factual and neutral tone. Never blame an individual. Focus on systems and processes.
5. Mandatory review. Never finalize without the review sub-agent phase.
6. No fluff in productions. Every element must add comprehension or structure. Remove empty sections and decorative diagrams. This does NOT apply to questioning: always confirm with the user, even when the answer seems obvious.

Interaction Model

Subjects below are a checklist, not sequential steps. Order is recommended, not imposed.

• Depth-first. Explore each subject fully before moving on. Dig into sub-topics as they emerge.
• Progress counter. Display "~N questions remaining" estimated from uncovered subjects. N can increase.
• On-the-fly corrections. Integrate corrections without formally returning to a previous subject.
• Natural conversation, structured document. The conversation can be messy. The final document is rigorous.

Subjects to Cover

Cover all subjects before production. Order is recommended, not imposed.

1. General context

• Who is writing? What incident? When? Who was involved? What system affected?

2. Timeline

• Build chronology event by event with timestamps. Iterative: "What happened next?"
• Propose a mermaid timeline diagram for validation.

3. Impact and severity

Multidimensional, no fixed scale (deliberate choice for genericity).

• User/client impact, financial impact, scope, probability of recurrence.

4. Detection and response

• How detected? Time to detection? Mitigation actions? Escalations?

5. Root cause (5 whys)

• Guide 5 whys iteratively, one "why" per question.
• Explore multiple causal branches separately. Distinguish root causes from aggravating factors.
• Propose mermaid causal diagram if non-trivial.
• Unknown root cause is valid: document as such, add "continue investigation" action.

6. What went well

• What helped detect/resolve faster? Good reflexes, communication, tools?

7. Corrective actions

• Each action: description, owner, deadline, priority.
• Distinguish corrective (this problem) from preventive (this class of problems).
• Backlog check: planned actions that could have prevented this?
• No action needed is valid with justification.

8. Lessons learned

• What to retain for the future? Learnings beyond corrective actions.

Production

Once all subjects are covered, generate two deliverables:

1. Post-mortem markdown file (pattern: YYYY-MM-DD-incident-title-post-mortem.md)
2. Short communication message

Write the file using the Write tool.

Review

Separate step from production.

1. Read review-agent-prompt.md (alongside this SKILL.md)
2. Dispatch sub-agent via Agent tool with the review prompt and the post-mortem file path
3. Present remarks to the user. Per remark, user decides: Approve, Modify, or Exclude (with justification)
4. Integrate decisions and regenerate
5. Loop until sub-agent finds no issues and user approves. No iteration cap.

Document Template

In French as reference. Adapt all headings, labels, and content to the user's language (Iron Rule 2). Statut is always "Brouillon"; the user updates it manually afterward.

# Post-mortem : [Titre de l'incident]

**Date de l'incident :** YYYY-MM-DD
**Date de redaction :** YYYY-MM-DD
**Redacteur :** [Nom]
**Participants :** [Noms des personnes impliquees]
**Statut :** Brouillon

## Resume

[3-5 phrases : ce qui s'est passe, la cause racine, l'impact, le statut actuel]

## Impact et severite

[Impact utilisateur/client]
[Impact financier / operationnel]
[Perimetre]
[Probabilite de recurrence]

## Timeline

[Chronologie avec timestamps ISO 8601]
[Diagramme mermaid si pertinent]

## Detection et reponse

[Comment l'incident a ete detecte]
[Delai entre debut et detection]
[Actions de mitigation/resolution]
[Escalades]

## Analyse des causes (5 whys)

[Chaine des pourquoi]
[Diagramme mermaid causal si pertinent]
[Distinction cause racine / facteurs aggravants]

## Ce qui a bien fonctionne

[Bonnes pratiques, bons reflexes, outils efficaces]

## Actions correctives

| Action | Type | Responsable | Deadline | Priorite |
|--------|------|-------------|----------|----------|
| ...    | Corrective / Preventive | ... | YYYY-MM-DD | Haute / Moyenne / Basse |

[Backlog check : actions pre-existantes qui auraient pu eviter l'incident]

## Lecons apprises

[Synthese : ce qu'on retient pour l'avenir]

Empty sections are removed. Mermaid diagrams only where they add value beyond text.

Communication Message Template

In French as reference. Adapt to user's language (Iron Rule 2).

Post-mortem : [Titre de l'incident]

Le [date], [description en 1 phrase de ce qui s'est passe].
L'analyse des causes et les actions correctives sont documentees dans le post-mortem : [LIEN]

Tone: informative but not rigid. Goal: encourage reading the full document.

Red Flags

• Asking 2+ questions in one message
• Skipping a subject because user seems impatient
• Generating without the review sub-agent
• Blame language ("X caused", "X forgot to")
• Mermaid diagram that restates the text
• Em-dashes or emojis in produced content
• Assuming instead of confirming with the user

Common Mistakes

Mistake	Fix
Dumping a list of questions	Ask ONE. Wait. Next based on answer.
Skipping 5 whys when cause seems obvious	Obvious cause is often a symptom. Dig deeper.
Corrective actions without owner/deadline/priority	All three required. No exceptions.
Generating without review	Always dispatch the review sub-agent.
Blaming individuals by name	Reference roles, not names.
Mermaid for simple timelines	3 events do not need a diagram.
Document language differs from conversation	Match throughout.