Lists multiple specific concrete actions: 'Cache-Control headers, ETags, conditional requests, Vary header, and no-store for sensitive data' - these are all distinct, concrete caching mechanisms.

Clearly answers both what ('HTTP caching for web APIs' with specific mechanisms) AND when ('Apply AUTOMATICALLY whenever building any API endpoint that serves data') with explicit trigger guidance.

Includes relevant technical terms like 'HTTP caching', 'Cache-Control', 'ETags', 'API endpoint', but missing common user variations like 'caching responses', 'browser cache', 'HTTP headers', or simpler terms users might naturally say.

Clear niche focused specifically on HTTP caching for APIs with distinct technical triggers (ETags, Cache-Control, Vary header) that are unlikely to conflict with other skills.

While the content is well-organized and avoids explaining basic concepts Claude knows, it's quite lengthy (~400 lines) with some repetition. The decision guide table and checklist partially duplicate information from the detailed sections, and some examples could be consolidated.

Excellent actionability with fully executable TypeScript/Express code examples, specific header values, a comprehensive decision table mapping endpoint types to exact Cache-Control values, and copy-paste ready middleware patterns. Every directive is demonstrated with working code.

Clear sequencing for implementing caching: the skill shows the problem first, then solutions organized by cache type, includes explicit validation via the checklist, and provides a decision guide for choosing the right approach. The ETag flow explicitly shows the conditional request handling sequence.

Content is well-structured with clear sections and a table of contents via headers, but everything is in one monolithic file. The verifiers are referenced at the end but the detailed content (400+ lines) could benefit from splitting advanced topics (ETag implementation, Vary header details) into separate reference files.