Code Refactor Skill for Claude

Code Refactor

Systematic code refactoring across files. Auto-switches to execution mode for 10+ files (90% token savings).

Mode Selection

• 1-9 files: Use native tools (Grep + Edit with replace_all)
• 10+ files: Automatically use code-execution skill

Execution example (50 files):

from api.code_transform import rename_identifier
result = rename_identifier('.', 'oldName', 'newName', '**/*.py')
# Returns: {'files_modified': 50, 'total_replacements': 247}
# ~500 tokens vs ~25,000 tokens traditional

When to Use

• "rename [identifier] to [new_name]"
• "replace all [pattern] with [replacement]"
• "refactor to use [new_pattern]"
• "update all calls to [function/API]"
• "convert [old_pattern] to [new_pattern]"

Core Workflow (Native Mode)

1. Find All Occurrences

Grep(pattern="getUserData", output_mode="files_with_matches")     # Find files
Grep(pattern="getUserData", output_mode="content", -n=true, -B=2, -A=2)  # Verify with context

2. Replace All Instances

Edit(
  file_path="src/api.js",
  old_string="getUserData",
  new_string="fetchUserData",
  replace_all=true
)

3. Verify Changes

Grep(pattern="getUserData", output_mode="files_with_matches")  # Should return none

Workflow Examples

Rename Function

• Find: Grep(pattern="getUserData", output_mode="files_with_matches")
• Count: "Found 15 occurrences in 5 files"
• Replace in each file with replace_all=true
• Verify: Re-run Grep
• Suggest: Run tests

Replace Deprecated Pattern

• Find: Grep(pattern="\\bvar\\s+\\w+", output_mode="content", -n=true)
• Analyze: Check if reassigned (let) or constant (const)
• Replace: Edit(old_string="var count = 0", new_string="let count = 0")
• Verify: npm run lint

Update API Calls

• Find: Grep(pattern="/api/auth/login", output_mode="content", -n=true)
• Replace: Edit(old_string="'/api/auth/login'", new_string="'/api/v2/authentication/login'", replace_all=true)
• Test: Recommend integration tests

Best Practices

Planning:

• Find all instances first
• Review context of each match
• Inform user of scope
• Consider edge cases (strings, comments)

Safe Process:

• Search → Find all
• Analyze → Verify appropriate
• Inform → Tell user scope
• Execute → Make changes
• Verify → Confirm applied
• Test → Suggest running tests

Edge Cases:

• Strings/comments: Ask if should update
• Exported APIs: Warn of breaking changes
• Case sensitivity: Be explicit

Tool Reference

Edit with replace_all:

• replace_all=true: Replace all occurrences
• replace_all=false: Replace only first (or fail if multiple)
• Must match EXACTLY (whitespace, quotes)

Grep patterns:

• -n=true: Show line numbers
• -B=N, -A=N: Context lines
• -i=true: Case-insensitive
• type="py": Filter by file type

Integration

• test-fixing: Fix broken tests after refactoring
• code-transfer: Move refactored code
• feature-planning: Plan large refactorings