Before You Refactor

Overview

Stop. Read the code that already exists. Understand the tests that protect it. Take small steps. Keep the tests green. This is a rigid skill. Run the checklist; don't skip steps. When assessing code (not actively refactoring), steps 1–2 and 6 are the assessment; report findings without editing.

When to invoke

Invoke when you're about to:

• Refactor existing code (extract function, inline, rename across multiple files, restructure a module)
• "Clean up" code you didn't write
• Rewrite a function or module because the existing one feels ugly, outdated, or wrong
• Replace an existing implementation with a "better" one
• Restructure tests, fixtures, or shared helpers used in more than one place
• Assess whether existing code needs refactoring (reading for smells, coupling, complexity)
• Review a refactoring proposal or PR that restructures code

If you're touching ≥3 lines of existing non-trivial logic to change its shape (not its behavior), invoke this skill.