Refactoring Patterns Skill

Safe transformations — same behavior, better structure.

Golden Rule

Tests pass before AND after.

When to Refactor

Trigger	Action
Feature is hard to add	Refactor first
Same bug twice	Refactor to prevent
"I don't understand"	Refactor for clarity

When NOT to Refactor

• No tests + time pressure
• Code won't change
• Right before release
• Should rewrite instead

Core Moves

Move	When
Extract Function	Does too many things
Inline Function	Body clear as name
Extract Variable	Complex expression
Rename	Name doesn't reveal intent
Move Function	Uses other class's data

Code Smells → Fix

Smell	Refactoring
Long function	Extract Function
Long param list	Parameter Object
Duplicate code	Extract Function
Feature envy	Move Function
Large class	Extract Class

Refactor vs Rewrite

Refactor	Rewrite
Core logic sound	Design is wrong
Tests exist	Untestable
<30% changes	>70% changes

Safe Workflow

Commit → Test → Small change → Test → Commit → Repeat

Synapses

See synapses.json for connections.