extract-patterns— agent skill

Extract reusable patterns from recent build artifacts.

Steps

1. Read .buildloop/build-claims.md and .buildloop/review-report.md if they exist.
2. Read recent git history: git log --oneline -5
3. Identify 0-5 reusable patterns -- things that went wrong, non-obvious solutions, or techniques worth remembering.
4. Check existing patterns in ~/.foundry/patterns/ to avoid duplicates.

Output

Write patterns to .buildloop/patterns-extracted.json:

[
  {
    "pattern_id": "kebab-case-id",
    "title": "Short descriptive title",
    "severity": "HIGH|MEDIUM|LOW",
    "keywords": ["keyword1", "keyword2"],
    "tech_stack": ["rust"],
    "issue": "What went wrong or what was non-obvious",
    "solution": {
      "planner": "What the planner should do differently",
      "reviewer": "What the reviewer should check for"
    }
  }
]

Rules

• Only extract genuinely reusable patterns, not task-specific details.
• Check for duplicates before writing.
• If nothing worth extracting, write an empty array [].