| name | refactoring |
| description | Guide code refactoring using Martin Fowler's catalog of behavior-preserving transformations. Use during TDD REFACTOR phase, when code smells are detected (duplication, long methods, feature envy), when discussing structural improvements, or before behavioral changes (Tidy First). |
Refactoring Skill
Apply behavior-preserving transformations to improve quality of any codes, including tests.
Core Principle
"Refactoring is a disciplined technique for restructuring an existing body of code, altering its internal structure without changing its external behavior." — Martin Fowler
Structural Changes Only
Allowed:
- Renaming for clarity
- Extracting functions/methods
- Removing duplication
- Simplifying expressions
- Moving files/modules between directories
- Reorganizing module boundaries
NOT allowed:
- Adding new functionality
- Fixing bugs (if you find one, write a failing test first)
- Changing observable behavior in any way
See library-application-criteria.md for public API constraints (libraries vs applications).
Refactoring Workflow
- Ensure tests pass (you need a safety net)
- Identify ONE smell to address
- Choose appropriate pattern from
patterns.md
- Apply mechanically in small steps
- Run tests after each step
- Commit when green
Safety Rules
- Never refactor with failing tests
- One pattern at a time
- Commit after each successful refactor
- Revert immediately if tests fail
