refactoring

Plan and execute incremental refactorings with characterization tests and phased gates.

Updated Feb 24, 2026

Search Tags:#testing #refactoring #safety #phases #legacy-code #design-improvement

Ready to run

npx skills add https://github.com/AymanKastali/pydentity --skill refactoring-aymankastali

💬 Prompt for ChatGPT / Claude Chat▼

Please help me install this Agent Skill.
Skill: refactoring
Source: https://github.com/AymanKastali/pydentity/tree/main/.claude/skills/refactoring
Command: npx skills add https://github.com/AymanKastali/pydentity --skill refactoring-aymankastali

SYSTEM DOCUMENTATION & REQUIREMENTS

What problem does it solve?

Provides a disciplined, test-backed approach to restructurings so observable behavior remains stable while improving design.

Core Features & Use Cases

Phased gates enforce safety before changes.
Characterization tests document legacy behavior to serve as a safety net.
Incremental proofs through small steps; each step is committed only when tests stay green.
Target design articulation to guide refactoring toward a cleaner, cohesive architecture.

Quick Start

Start by writing characterization tests for the current behavior, then perform a single small refactoring step, run the full test suite, and commit if green.

Frequently Asked Questions about refactoring

High-intent search queries and answers about installing and using this skill.

FAQPage Schema

How do I refactor legacy code safely without breaking existing behavior?▼

Safe legacy code refactoring requires writing characterization tests first to document current behavior, then applying incremental structural changes while keeping the test suite green to preserve observable behavior.

What is a characterization test and when do I need it for refactoring?▼

A characterization test captures and documents the current behavior of legacy code. You need it before refactoring to establish a safety net that detects any unintended observable behavior changes during structural improvements.

What is the best way to restructure a large legacy codebase incrementally?▼

The best way to restructure large legacy codebases is using phased gates with dependency-aware sequencing, committing only small reversible steps when tests pass to minimize risk during large-scale restructuring.

Do I need existing test coverage to start refactoring legacy code?▼

You do not need prior test coverage to start refactoring legacy code. The process begins by writing characterization tests against current behavior to establish the safety net before making any structural changes.

Why does my refactoring break tests even with small code changes?▼

Refactoring may break tests if changes are not dependency-aware or lack explicit target design articulation. Sequencing steps according to dependencies and verifying behavior after each small change prevents failures.