Tidy First — AI Code Refactoring Skill for Agents

What is Tidy First?

Kent Beck's code maintenance methodology: make small structural improvements before behavior changes.

TL;DR: Kent Beck's code maintenance methodology. Small structural improvements before behavior changes. 15 tidying patterns (guard clause / extract helper / dead code / rename). Essential skill for AI agent code maintenance.

15 Tidyings

1. Guard Clauses — early returns reduce nesting
2. Dead code deletion
3. Symmetry normalization
4. Extract helper function
5. Inline helper function
6. Reorder statements
7. Explicit parameters 8–15. Chunking / constants / renaming / dedup / simplify conditionals / flatten / split phase / introduce types

Rules

• Commit structure and behavior separately
• Each tidying < 10 lines of change
• Only tidy code you're about to modify