Conciseness

The coverage bullet list and workflow are lean, but the Constraints section states the compile requirement five times over ('Before applying REST changes, ensure the project compiles', 'MANDATORY', 'PREREQUISITE', 'SAFETY', 'BLOCKING CONDITION'), and 'When to use this skill' duplicates the frontmatter description verbatim. This fits 'mostly efficient but includes some unnecessary explanation or could be tightened' rather than 4, where padding would be only minor.

Actionability

There are concrete executable commands ('./mvnw compile', 'mvn clean verify') and a specific reference path, but the actual domain guidance is entirely deferred, and workflow steps 2–3 are generic ('Gather scope and decide target improvements', 'Implement or refactor configuration/code following the reference patterns'). This matches 'some concrete guidance but incomplete; missing key details' rather than 4, which expects the guidance to be mostly executable with only minor gaps.

Workflow Clarity

The 4-step sequence is clear with explicit checkpoints: mandatory compile before ('Run ./mvnw compile... before applying any change'), a stop condition ('If compilation fails, stop immediately'), and post-change verification ('Run ./mvnw clean verify... after applying improvements'). It falls short of 5 because there is no fix-and-retry feedback loop after verification fails and no checklist for the improvement steps.

Progressive Disclosure

The body is a concise overview that delegates all detail to a single reference signaled twice by exact path ('references/402-frameworks-quarkus-rest.md' in workflow step 1 and as a markdown link in the Reference section), which exists and is one level deep with no nested references. This matches the 'clear overview with well-signaled one-level-deep references' anchor.

Specificity

Opens with three concrete verbs ('design, review, or improve REST APIs with Quarkus REST (Jakarta REST)') and comprehensively enumerates specific capabilities: 'exception mappers', 'Idempotency-Key', 'ETag / If-Match', 'Cache-Control', 'Sunset / Deprecation headers', 'RFC 7807 Problem Details', 'pagination, sorting, and filtering'. This matches the 'multiple specific concrete actions; comprehensive coverage' anchor, not 4, which reserves 'minor gaps in coverage'.

Completeness

Both questions are answered explicitly: 'what' via 'design, review, or improve REST APIs with Quarkus REST... including resource classes, HTTP methods, status codes...' and 'when' via the opening 'Use when you need to...' plus a second concrete trigger list ('This should trigger for requests such as...'). This is the anchor-5 pattern; level 4 requires a 'when' that 'could be more explicit', which does not apply here.

Trigger Term Quality

Natural user phrases appear both inline ('pagination', 'idempotency', 'ETag concurrency', 'deprecation headers', 'exception mappers') and in an explicit trigger list ('Review or improve JAX-RS resources in a Quarkus project; Design HTTP APIs with validation and error handling on Quarkus'). Synonyms are covered ('Quarkus REST (Jakarta REST)', 'JAX-RS'), matching the comprehensive-coverage anchor rather than the 'a few natural terms missing' level 4.

Distinctiveness Conflict Risk

The niche is unambiguous — Quarkus REST / JAX-RS resource design — with triggers that would not fire for generic REST, validation, or non-Java skills. Mentions of 'Bean Validation' and 'security-aware boundaries' are framed as boundary concerns inside the Quarkus REST scope, not standalone triggers, so overlap risk is minimal rather than 'minor' (level 4).