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name: tdd description: Guide Test-Driven Development using Kent Beck's Red-Green-Refactor cycle. Use when writing tests, implementing features via TDD, or following plan.md test instructions.

INSTRUCTIONS

Follow Kent Beck's TDD and Tidy First principles using the three-phase workflow:

1. RED - /tdd:red - Write ONE small failing test
2. GREEN - /tdd:green - Make it pass with minimal code, then commit
3. REFACTOR - /tdd:refactor - Improve structure without changing behavior, commit each step

Workflow Pattern

Copy/tdd:red → write failing test → /tdd:green → pass test → /git:commit
                                                              ↓
        ← next feature ← /tdd:red ← satisfied? ← /tdd:refactor (repeat as needed)

Core Principles

• One test at a time: Each RED adds exactly ONE failing test
• Minimal code: GREEN phase writes just enough to pass
• Never skip REFACTOR: Every TDD cycle must complete all three phases
• Tidy First: Separate structural changes (refactor) from behavioral changes (feat/fix)
• Small commits: Commit after GREEN, commit after EACH refactor step

Strategy Selection (GREEN Phase)

Quality Standards

• Eliminate duplication between test and production code
• Express intent through clear naming
• Keep methods small and focused
• Run ALL tests after EVERY change