The opening paragraph and the 'Explain' section restate background (what stack traces reveal, the OWASP A09 framing, CVE lookup) that Claude already knows, which the guidelines penalize, though the Quick Reference and Check/Fix sections stay lean.

The guidance flags concrete things to look for (error.stack, raw error.message, internal paths) but stops short of showing how to implement the central error handler, leaving the actionable guidance incomplete.

The Check/Fix/Explain/Code Review structure gives a present sequence, but there is no explicit validation or verification checkpoint confirming the fix fully removes the disclosure.

A concise ~32-line overview points via a clearly signaled, one-level-deep reference to the real file references/rule.md for full implementation details, exemplifying clean progressive disclosure.

The description names concrete review targets ('error handling middleware, API route handlers, or server responses') but describes a single review action rather than listing multiple distinct capabilities, matching the 'names domain and some actions' anchor.

It explicitly answers both what (reviewing responses for sensitive disclosure) and when (an explicit 'Use when...' clause listing the trigger contexts), satisfying the highest anchor.

'Use when reviewing error handling middleware, API route handlers, or server responses for security-sensitive information disclosure' uses natural trigger phrases a user would actually say, with good coverage of relevant terms.

The scope is a distinct niche — security-sensitive information disclosure in production error responses — with triggers unlikely to fire for unrelated skills.