# Tdd Refactor Expert

> Guidance and checklists for the Refactor phase of TDD, ensuring clean code without breaking tests.

- Skill: `jcorpac/tdd-refactor-expert` (Agent Skill)
- Install (CLI): `npx skillmds@latest add jcorpac/tdd-refactor-expert`
- Raw SKILL.md: https://api.skillmd.com/api/skills/jcorpac/tdd-refactor-expert/raw
- Safety review: pending
- Works with: Claude Code, Claude.ai, OpenAI Codex
- Category: Coding & Dev Tools
- Author: jcorpac (https://skillmd.com/u/jcorpac)
- Updated: 2026-09-17
- Page: https://skillmd.com/skills/jcorpac/tdd-refactor-expert

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# TDD Refactor Expert

Refactoring is about improving the design of existing code without changing its external behavior.

## Refactoring Checklist
- [ ] **Descriptive Naming**: Are variables, functions, and classes named after what they *do*?
- [ ] **Small Units**: Can large functions be broken down? (Goal: < 20 lines).
- [ ] **Dry Principle**: Is there any duplicated logic that can be extracted?
- [ ] **Single Responsibility**: Does each class/function do only one thing?
- [ ] **Consistent Style**: Does the code follow the project's style guide?

## Common Patterns
1. **Extract Method**: Move a fragment of code to a new function.
2. **Rename Variable**: Clarify the purpose of a variable.
3. **Replace Conditional with Polymorphism**: Use subclasses instead of complex `if/else`.
4. **Introduce Parameter Object**: Group related parameters into a class.

## Safety First
1. Run all tests (Green).
2. Apply **one** small refactoring.
3. Run all tests again (Should still be Green).
4. Repeat.