refactor-safe

name	refactor-safe
description	Use for safe refactors that preserve behavior. Keep diffs small and verification strong.
allowed-tools	Read, Grep, Glob, Bash, Edit, Write
when_to_use	Use automatically only when the change must leave behavior identical.
argument-hint	[file or module to refactor]

refactor-safe

Behavior must be identical before and after. If tests don't exist: write them FIRST, then refactor.

1. One concern per diff: rename | move | extract | restructure — never combine two.

2. Run tests before edit, record baseline. Apply ONE mechanical transformation only. Run same tests after — must be identical pass/fail.

3. Diffs >150 lines → split into sequential mini-refactors. No features/bugfixes in same diff.

4. Read budget: refactored file + grep for symbol importers + existing test file. Imports updated across independent files → apply in one parallel batch.

5. Refactor that moves a module boundary (extract, restructure): run /arch-check before and after. The point of a boundary refactor is that violations go down — unmeasured, "cleaner" is an opinion.

Deep reference: agent_docs/testing-strategy.md (baseline coverage before refactor) · agent_docs/architecture.md (module boundary rules).

Output

CONCERN: [rename | move | extract | restructure]
· [files changed — count]
TEST BEFORE: [N passed] → TEST AFTER: [N passed — ✓ identical]
RISK: low