- Write tests that define expected behavior
- Tests MUST fail (exit code 1)
- Use CI=true or --run flag, never watch mode
- Apply timeout guards (60s) to prevent hanging
- Record exit code as evidence
2. GREEN Phase - Minimal Implementation
- Write the minimal code to make tests pass
- Do NOT add features not covered by tests
- Do NOT optimize prematurely
- Tests MUST pass (exit code 0)
- Record exit code as evidence
3. REFACTOR Phase - Quality Improvement
- Apply SOLID principles and clean code patterns
- Improve naming, reduce coupling
- Remove duplication
- Run tests after EACH refactoring step
- Tests MUST remain passing (exit code 0)
4. Coverage Gate
- Measure coverage: statements, branches, functions, lines
- Minimum 80% overall coverage required
- Iterate: write additional tests for gaps until threshold met
- Maximum 3 convergence iterations
Rules
- Never skip the RED phase
- Never accept GREEN without exit code 0
- Never use watch mode in CI
- Always record evidence (exit codes, coverage numbers)
- Enforce 80% coverage threshold
When to Use
- All code implementation tasks
- Feature development
- Bug fixes (write regression test first)
Agents Used
tdd-guide(primary consumer)code-reviewer(validates test quality)