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.