Names the domain (Expo Router apps) and lists several topic areas (styling, components, navigation, animations, patterns, native tabs), but these are categories rather than concrete actions. It doesn't describe specific actions like 'configure tab navigation', 'implement animated transitions', or 'set up file-based routing'.

It describes what the skill covers (building apps with Expo Router across several topics) but completely lacks any 'Use when...' clause or explicit trigger guidance for when Claude should select this skill. Per the rubric, a missing 'Use when...' clause caps completeness at 2, and the 'what' portion is also somewhat weak (listing topic areas rather than concrete capabilities), so this scores a 1.

Includes some relevant keywords like 'Expo Router', 'navigation', 'animations', 'native tabs', and 'styling' that users might mention. However, it's missing common variations and natural phrases users would say such as 'React Native', 'mobile app', 'screen transitions', 'stack navigator', 'file-based routing', or '.tsx'.

The mention of 'Expo Router' specifically provides some distinctiveness, but the broad terms like 'styling', 'components', 'animations', and 'patterns' could easily overlap with general React Native skills, CSS/styling skills, or animation-focused skills.

Generally efficient with good use of bullet points and code examples, but includes some unnecessary explanation (e.g., the lengthy Expo Go vs custom builds section explaining when each works, and some guidance Claude would already know like 'always use import statements at the top of the file'). The 'When Expo Go Works' section listing obvious features is somewhat redundant.

Provides fully executable, copy-paste ready code examples for navigation, context menus, link previews, sheets, modals, and route structures. Specific library preferences are clearly stated with concrete alternatives. The common route structure section is particularly actionable with complete file-by-file examples.

The Expo Go workflow (try first, then custom build) is clearly sequenced, and the common route structure provides a clear pattern. However, there are no validation checkpoints for the multi-step processes like restructuring navigation or setting up tabs. Missing feedback loops for operations like 'always remove old route files when moving or restructuring navigation' — no verification step is provided.

Excellent progressive disclosure with a clear references section at the top pointing to 11 well-organized reference files covering specific topics (route structure, tabs, icons, controls, etc.). The main SKILL.md serves as a concise overview with essential patterns inline, while detailed topics are appropriately delegated to one-level-deep reference files with clear descriptions.