Use when restructuring existing code without intending to change its behavior — extracting functions, renaming across files, splitting modules, or swapping an implementation. Makes the agent pin current behavior with tests first, change in small verified steps, and prove behavior is unchanged, so a
Use when restructuring existing code without intending to change its behavior — extracting functions, renaming across files, splitting modules, or swapping an implementation. Makes the agent pin current behavior with tests first, change in small verified steps, and prove behavior is unchanged, so a "cleanup" never silently breaks something.