Don't Repeat Yourself Find and eliminate duplication across your codebase. Every duplicate is a future bug — when you fix something in one place but forget the copy, users hit the unfixed version. This skill audits and refactors. For building features, use build . For general performance optimization, use optimize . For database schema design from scratch, use database . For UI component selection, use ui-patterns . Two Modes | Mode | When | Scope | Time | |------|------|-------|------| | Quick scan | After building a feature, or on request | Recent changes vs. existing codebase | 2-5 minutes…