Conciseness

The body is a lean index: terse one-line directives like 'Use FlashList for large lists' and 'Animate only transform and opacity' assume Claude's competence and avoid teaching React Native basics. Minor over-explanation could be trimmed — the 'Each rule file contains:' bullet list and the priority table partially duplicate the category headings that follow — so it fits the 'efficient; minor instances that could be trimmed' anchor rather than the every-token-earns-its-place level of a 5.

Actionability

Most rules are concrete, immediately executable directives such as 'Use expo-image for all images', 'Use Pressable over TouchableOpacity', and 'Keep native dependencies in app package' — specific enough to act on without opening rule files. It is not a 5 because the body contains no code examples or commands and defers all implementation detail to files that are not present in this bundle, leaving minor gaps for the common cases.

Workflow Clarity

The usage flow is discernible and unambiguous for a reference-index skill: 'When to Apply' states the conditions, the priority table and prefixed rule IDs provide lookup structure, and 'Read individual rule files for detailed explanations' directs next steps. It is above 3 because the sequence and navigation are explicit, but below 5 because 'How to Use' gives only two example paths and no guidance on locating the right rule for a given task beyond scanning categories.

Progressive Disclosure

The body is well structured as an index with clearly signaled references ('rules/list-performance-virtualize.md', 'AGENTS.md'), but scoring against the actual bundle shows no referenced files, no rules/ directory, and no AGENTS.md exist alongside SKILL.md — the navigation the body promises cannot be followed. References present but the structure does not back them, matching the 'some structure but could be better organized' anchor rather than the 4 anchor's 'minor organization gaps'.

Specificity

Quotes like 'optimizing list performance', 'implementing animations', and 'working with native modules' name several concrete actions within the React Native/Expo domain, matching the 'several specific actions; minor gaps' anchor. It falls short of 5 because body-covered areas such as navigation, monorepo structure, and UI patterns are absent from the description, and 'best practices' is somewhat generic; it is clearly above 3 since multiple distinct concrete actions are listed, not just 1-2.

Completeness

The 'what' is explicit ('React Native and Expo best practices for building performant mobile apps') and the 'when' is explicit and stated twice with concrete triggers ('Use when building React Native components, optimizing list performance, implementing animations, or working with native modules. Triggers on tasks involving React Native, Expo, mobile performance, or native platform APIs.'). This clearly matches the anchor for answering both what AND when with concrete trigger phrases; a 4 would require the 'when' to be less explicit, which it is not.

Trigger Term Quality

Natural phrases users would say appear directly: 'React Native', 'Expo', 'building React Native components', 'optimizing list performance', 'implementing animations', 'native modules', 'mobile performance'. This is good keyword coverage with a few natural terms missing (e.g., iOS/Android app performance, specific libraries like Reanimated or FlashList), fitting the 'good coverage; a few natural terms missing' anchor rather than the comprehensive synonym/extension coverage of a 5.

Distinctiveness Conflict Risk

React Native/Expo mobile development is a clear niche with distinct triggers ('native modules', 'native platform APIs', 'mobile performance') that generic React, web, or document skills would not match, fitting the 'clear niche with distinct triggers; minimal conflict risk' anchor. It does not sit at 4 because the trigger terms are platform-specific enough that overlap with a closely related non-RN skill is minimal.