# Refactor

> Safely refactor code with test coverage as a safety net

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

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Refactor `$ARGUMENTS` safely.

## Process

### 1. Understand the current state
- Read the code and its tests
- Identify what the code does, its callers, and its dependencies
- If there are no tests, WRITE TESTS FIRST — you need a safety net before changing anything

### 2. Plan the refactoring
- State what you're changing and why (clearer naming, reduced duplication, better structure)
- List the specific transformations (extract function, inline variable, move module, etc.)
- Check: does this change any external behavior? If yes, this isn't a refactor — reconsider.

### 3. Make changes in small, testable steps
- One transformation at a time
- Run tests after EACH step — not at the end
- If a test breaks, undo the last step and make a smaller change

### 4. Verify
- All existing tests pass
- Lint and typecheck pass
- The public API hasn't changed (unless that was the explicit goal)
- The code is objectively simpler — fewer lines, fewer branches, clearer names

## Rules
- If you can't run the tests, don't refactor
- Never mix refactoring with behavior changes in the same commit
- If the refactoring is large (10+ files), break it into multiple commits