Refactoring Patterns

---
name: refactoring-patterns
description: 'Apply named refactoring transformations to improve code structure without changing behavior. Use when the user mentions "refactor this", "code smells", "extract method", "replace conditional", "technical debt", "move method", "inline variable", "decompose conditional", or "clean up this messy code". Also trigger when cleaning up legacy code, preparing code for new features by restructuring, or identifying which transformation fits a specific code smell. Covers smell-driven refactoring, safe transformation sequences, and testing guards. For code-quality foundations, see clean-code. For managing complexity, see software-design-philosophy.'
license: MIT
metadata:
  author: wondelai
  version: "1.4.1"
---

# Refactoring Patterns Framework

A disciplined approach to improving the internal structure of existing code without changing its observable behavior. Every refactoring follows the same loop: verify tests pass, apply one small structural change, verify tests still pass.

## Core Principle

**Refactoring is not rewriting. It is a sequence of small, behavior-preserving transformations, each backed by tests.** You never change what the code does — only how it is organized. Big-bang rewrites fail because they combine structural change with behavioral change, making it impossible to know which broke things.

**The foundation:** Bad code is a natural consequence of delivering under time pressure, not a character flaw. Code smells are objective signals of degraded structure; the smell catalog tells you *where* to look, and the refactoring catalog tells you *what to do*.

## Scoring

**Goal: 10/10.** Score structural quality by how many of the eight [Quick Diagnostic](#quick-diagnostic) rows pass — `score = round(passed / 8 × 10)`, adjusting down when a single smell is severe. Bands:
- **9-10**: no obvious smells remain, each function does one thing, names reveal intent, duplication is eliminated, conditionals use polymorphism where apt, and tests cover the refactored paths.
- **5-6**: a few smells remain (a Long Method, some duplication) but structure is mostly sound.
- **≤3**: pervasive smells — tangled conditionals, God classes, duplication everywhere — or no tests to refactor safely.… load the full skill through Skill Me