Code Refactoring: Keep Code Small
Refactor overly large code you just added or extended into smaller, more focused components.
When to Use This Skill
Use this skill when:
- Functions or methods are too long (typically >50 lines)
- Classes have too many responsibilities
- Files have grown too large or handle multiple concerns
- Code has deeply nested blocks
- After implementing a feature and noticing bloat
Critical Rule: Refactor As You Go
When adding new logic to an existing function, ALWAYS check whether the function is already long. If it is, extract a new method/function for the new logic rather than inlining it. Do NOT bloat existing functions further — refactoring is not a separate step to do later; it must happen at the time of writing.
This applies even when the new code is "just" 20-30 lines. Adding 30 lines to a 100-line function makes it a 130-line function that now needs refactoring. The correct approach is to never let it get that far.
Instructions
Step 1: Identify the Bloat
Review your recent changes (committed or uncommitted) to find:
- Functions or methods that are too long
- Classes that have too many responsibilities
- Files that have grown too large
- Deeply nested code blocks
- New logic inlined into already-long functions (this is the most common mistake — catch it early)
Step 2: Clarify Scope (If Needed)
If the bloat is not obvious, ask the user to clarify which specific code units they want refactored before proceeding.
Step 3: Refactor
Once the bloat is identified:
- Extract logical sub-operations into separate functions/methods
- Split large classes following Single Responsibility Principle
- Move related functionality into separate modules/files
- Reduce nesting levels by extracting guard clauses or helper functions
- Ensure each unit does one thing well (UNIX Philosophy)
- Deduplicate repeated structures (e.g. lookup tables defined in multiple places should become shared constants)
Step 4: Verify
After refactoring:
- Run linters and tests if available
- Verify the code still works as expected
- Check that the solution is clearer and more maintainable
- Ensure the refactoring improved readability
Goal
Break down large, complex code units into smaller, focused components that are:
- Easier to understand
- Easier to test
- Easier to maintain
Each function, class, or file should have a clear, single purpose.