refactor-agent

Refactor Agent

Quick Reference — see parent for full agent ecosystem.

The Refactor Agent restructures code to improve readability, maintainability, and extensibility without changing external behavior. It systematically identifies high-complexity functions, duplicated logic, dead code, and tightly coupled modules; then applies targeted refactorings (extract method, split module, introduce interface, remove duplication) with verification that all existing tests still pass. Its mantra: make the change easy, then make the easy change.

When Not to Use

• Simple or one-off tasks — if the task is straightforward, direct execution is faster than structured methodology.
• Already established workflows — follow existing team conventions rather than introducing new frameworks.
• When automation overhead exceeds benefit — for very small scopes, the setup cost may not be justified.

Dependencies

• Python 3.8+ or Node.js 18+
• Access to relevant APIs/services for your specific use case
• Basic understanding of the domain concepts

Commands

# Refer to the skill's usage section for specific commands
# Adapt these to your workflow

Key Responsibilities

• Measure complexity: Calculate cyclomatic complexity, cognitive complexity, and coupling metrics to identify the files that need refactoring most
• Apply pattern-driven refactors: Extract methods, split monoliths, introduce abstractions, remove dead code — each with a defined before/after signature
• Preserve behavior: Run the full test suite before and after every refactoring step to confirm zero behavioral changes

Code Example

"""Minimal refactor agent pattern — analyze and restructure."""

import json, sys
from pathlib import Path

def analyze_complexity(file_path: str) -> dict:
    """Analyze a file for refactoring candidates."""
    content = Path(file_path).read_text()
    lines = content.split("\n")

    functions = []
    current_fn = None
    fn_lines = 0
    branch_count = 0

    for i, line in enumerate(lines):
        stripped = line.strip()
        if stripped.startswith("def ") or stripped.startswith("async def "):
            if current_fn:
                functions.append({
                    "name": current_fn, "lines": fn_lines,
                    "branches": branch_count, "line": i - fn_lines + 1
                })
            current_fn = stripped.split("(")[0].replace("def ", "").replace("async ", "")
            fn_lines = 1
            branch_count = 0
        elif current_fn:
            fn_lines += 1
            if any(kw in stripped for kw in ["if ", "elif ", "for ", "while ", "and ", "or "]):
                branch_count += 1

    if current_fn:
        functions.append({
            "name": current_fn, "lines": fn_lines,
            "branches": branch_count, "line": len(lines) - fn_lines + 1
        })

    candidates = [f for f in functions if f["branches"] > 10 or f["lines"] > 50]

    return {
        "file": file_path, "total_lines": len(lines),
        "functions": functions,
        "candidates": candidates,
        "recommendations": [
            f"Extract method: {c['name']} ({c['branches']} branches, {c['lines']} lines)"
            for c in candidates
        ]
    }

if __name__ == "__main__":
    result = analyze_complexity(sys.argv[1])
    print(json.dumps(result, indent=2))