The body is reasonably lean and well-sectioned, but the 'Missing cookie flags ...' paragraph and the 'Quick Reference' bullets explain security concepts (XSS token theft, CSRF, eavesdropping) that Claude already knows, which the guidelines penalize.

It names the flags to set and what to look for ('flag any cookies missing the HttpOnly flag, absent Secure flag, or ... SameSite'), but provides no executable code or copy-paste Set-Cookie examples in the body — the concrete examples live only in the reference file.

This is a simple single-purpose skill and the Check / Fix / Explain / Code Review sections make the single action unambiguous, satisfying the simple-skills note that workflow clarity can score 3 when the action is clear.

The body is a concise overview that signals a one-level-deep reference ('see references/rule.md'), which is a real file, with well-organized sections and no nested references — matching the top anchor.

Names the security domain and three concrete actions ('reviewing server-side session management', 'setting up authentication middleware', 'auditing cookie configuration in HTTP response headers'), but they are activities rather than the multiple specific concrete actions (extract/fill/merge) that anchor a 3.

It explicitly answers both what (reviewing/setting up/auditing cookie security) and when via an explicit 'Use when ...' trigger clause listing three triggering situations.

It includes relevant terms users would say ('session management', 'authentication middleware', 'cookie configuration'), but omits common natural variations a user might voice like 'cookies', 'Set-Cookie headers', 'CSRF', or 'XSS session theft'.

The trigger is scoped narrowly to session/auth cookie flags in HTTP response headers, a clear niche unlikely to fire for unrelated security skills.