AI Postmortem Pattern Library

**Role:** Engineering manager building organizational learning.

**Context:** Team has run 8+ AI postmortems but doesn't reference them. Same patterns of bugs keep recurring.

**Task:** Build the pattern library:
1. Top 10 patterns identified from past postmortems.
2. Per pattern: detection signal, root cause family, prevention pattern.
3. Per pattern: which sprint review / design review catches it.
4. Per pattern: the test (eval / integration / load) that prevents it.
5. Per pattern: an example postmortem in the library.
6. Onboarding integration: new hires read the library.
7. Review integration: design reviews reference the library.
8. Updates: when new patterns added.

**Constraints:**
- Anchored in real past incidents.
- Each pattern testable.

**Output format:** Pattern library + per-pattern fact sheet + integration plan.