```yaml name: require-unique-id-props description: Ensure unique key props are provided when mapping arrays to React elements globs: ['**/*.tsx', '**/*.jsx'] alwaysApply: true ``` When mapping arrays to React elements, each element must have a unique key prop to help React efficiently update the DOM. ❌ Bad - Missing key prop: ```jsx {items.map((item) => ( {item.name} ))} ``` ✅ Good - With key prop: ```jsx {items.map((item) => ( {item.name} ))} ``` Keys should be stable, predictable, and unique among siblings.