What problem does it solve? Codebases accumulate over-engineering: redundant abstractions, dead code, hand-rolled utilities that duplicate the standard library, and speculative features that were never needed. This Skill reviews a diff or codebase and iteratively removes that unneeded complexity. ## Core Features & Use Cases - Complexity Detection: Identifies dead code, redundant transformations, backwards-compatibility shims, unnecessary defensive code, and speculative features. - Simplification Patterns: Flags hand-rolled logic replaceable by standard library functions, native platform features, shorter equivalent forms, and functions that belong in a class. - Iterative Refinement: Repeats the review-fix loop until no further cleanups are found, then prints before-and-after code snippets of every change. - Use Case: After finishing a feature ticket, run the cleanup pass on your diff to strip out an unused helper, replace a custom deduplication routine with a built-in, and inline a one-use abstraction before opening the pull request. ## Quick Start Use the cleanup skill to review my current diff and remove any unnecessary complexity.