Write failing tests first, then minimal code to pass, then refactor cleanly.
---
name: test-driven-development
description: Use when implementing any feature or bugfix, before writing implementation code
---
# Test-Driven Development (TDD)
## Overview
Write the test first. Watch it fail. Write minimal code to pass.
**Core principle:** If you didn't watch the test fail, you don't know if it tests the right thing.
**Violating the letter of the rules is violating the spirit of the rules.**
## When to Use
**Always:**
- New features
- Bug fixes
- Refactoring
- Behavior changes
**Exceptions (ask your human partner):**
- Throwaway prototypes… load the full skill through Skill Me