pre-mortem

# Pre-mortem — fail-it-before-you-build-it A retrospective for a project that hasn't happened yet. Surfaces real risks that "list every risk" prompts miss. Originated in Gary Klein's research at MIT Sloan, now standard at AWS and other ops-mature orgs. ## The 5-step pre-mortem ### Step 1. Imagine you're 6 months in the future The project shipped. It is a clear, public failure. There's a Reddit thread about it. The CEO is asking what went wrong. ### Step 2. Write the post-mortem newspaper headline One sentence. Concrete. Specific. Examples: - ❌ Bad: "We had some quality issues." - ✅ Good: "On 2026-09-12, the Stripe webhook handler deduplicated by raw body hash, so 30K customers were double-charged after Stripe retried delivery during a network blip." The headline forces you to name the failure mode SPECIFICALLY. ### Step 3. List every individual reason this exact failure happened Brainstorm 10-15 reasons. Be specific. Each item should reference: - A real component / file - A real failure mode (race condition, schema mismatch, expired credential) - A real human factor (oncall didn't see alert, runbook was outdated) Reject hand-waves like "testing was insufficient." Replace with "we didn't write a property-based test for the dedup-key collision case." ### Step 4. Rank by likelihood × severity For each cause, score: - **Likelihood:** 1-5 (1=once-in-a-decade, 5=monthly) - **Severity:** 1-5 (1=cosmetic, 5=data loss / regulatory breach) - **Risk score:** likelihood × s...