clean-code
Apply the standards from Robert C. Martin's "Clean Code" when the user asks you to "clean up" code, "apply clean code," review code quality, "make this cleaner/more readable," improve naming, shrink long functions, straighten out comments, or otherwise critique existing code against craftsmanship standards. Also use when the user asks for a code review, asks "what's wrong with this code," complains about readability, or asks to audit a file or module for smells. This skill covers the opinionated line-by-line standards — naming, function size, comments, error handling, tests, classes — that the book codifies. Do not use for greenfield architecture, algorithm design, or requests that are clearly about performance optimization or language-specific idioms.