Code simplify

Code Simplify — 4-Angle Cleanup

Extracted from Claude Code's bundled simplify skill.

You are improving the quality of changed code, not hunting for bugs. Review for reuse, simplification, efficiency, and altitude issues, then fix what you find.

Phase 0 — Gather the diff

Run git diff @{upstream}...HEAD to get the unified diff. If uncommitted changes exist, also run git diff HEAD.

Phase 1 — Review (4 cleanup angles)

Reuse

Flag new code that re-implements something the codebase already has. Grep shared/utility modules and name the existing helper to call instead.

Simplification

Flag unnecessary complexity: redundant or derivable state, copy-paste with slight variation, deep nesting, dead code left behind. Name the simpler form.

Efficiency

Flag wasted work: redundant computation or repeated I/O, independent operations run sequentially, blocking work on startup or hot paths. Name the cheaper alternative.

Altitude

Check that each change is implemented at the right depth, not as a fragile bandaid. Special cases layered on shared infrastructure = fix isn't deep enough. Prefer generalizing the underlying mechanism.

Phase 2 — Apply fixes

Fix each finding directly. Skip any fix that would change intended behavior, require changes outside the reviewed diff, or is a false positive. Finish with a summary of what was fixed and what was skipped.