Conciseness

The body is lean and assumes Claude's competence — no concept explanations, no filler — but the Quick Reference table and the Problem -> Skill Mapping table list the same 12 reference files twice, and 'When to Apply' restates the frontmatter description. Efficient overall with trimmable redundancy, matching the 4 anchor rather than the 5 anchor's 'every token earns its place'.

Actionability

Concrete, checkable guidance throughout: 'Run npx brownfield <command> --help before relying on any flag table', named placeholders (<framework_target_name>, <android_module_name>, <registered_module_name>), 'inspect package.json and app.json', and 'brownfield.config.*'. As an instruction-only router skill the absence of full code blocks is not penalized per the rubric's scoring note, but it stops short of the 5 anchor's copy-paste-ready commands covering common cases.

Workflow Clarity

A clear 5-step Migration Strategy, a must-run-first Path Selection Gate with a disambiguation fallback ('If still unclear, ask one disambiguation question'), and explicit validation checkpoints ('Validate each packaging command before moving to host integration'; step 4 includes 'validate startup/runtime'). It does not reach 5 because fix-and-retry feedback loops — what to do when a packaging validation or startup check fails — are not specified.

Progressive Disclosure

Exemplary router structure: an overview body pointing to 12 one-level-deep reference files, all of which exist on disk and cross-link only to siblings (verified — no nested reference chains), plus canonical external docs for long platform snippets. Both file-oriented (Quick Reference) and task-oriented (Problem -> Skill Mapping) navigation are present with accurate descriptions, matching the 5 anchor's 'well-signaled one-level-deep references; easy navigation'.

Specificity

The description lists multiple concrete actions with specific artifact formats: 'setting up the integration, packaging XCFramework or AAR artifacts, adding React Native surfaces to native hosts', all anchored to a named tool (@callstack/react-native-brownfield). This matches the anchor for comprehensive coverage of specific concrete actions; there are no minor coverage gaps that would justify a 4.

Completeness

It explicitly answers both questions: 'Implements an accepted incremental brownfield migration from native iOS or Android to React Native or Expo using @callstack/react-native-brownfield' (what) and 'Use after the brownfield path has been selected, when setting up the integration, packaging XCFramework or AAR artifacts, or adding React Native surfaces to native hosts' (when, with three concrete trigger situations). This matches the 5 anchor exactly.

Trigger Term Quality

Good natural-term coverage ('brownfield migration', 'native iOS or Android', 'React Native or Expo', 'XCFramework or AAR artifacts', 'native hosts') that users in this domain would actually say. It falls short of the 5 anchor because common phrasings like 'add React Native to an existing app' or 'embed React Native in a native app' are missing, while clearly exceeding the 3 anchor's 'missing common variations' level.

Distinctiveness Conflict Risk

The niche tool name and the explicit temporal boundary 'Use after the brownfield path has been selected' cleanly separate it from the sibling assessment skill and from general React Native work. Minimal conflict risk, matching the 5 anchor's 'clear niche with distinct triggers'.