Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

With annotations present, the description adds real behavioral context beyond them: the one-hour caching window returning a stored sample (with cached_at), that out-of-host URLs are counted but never requested, and that a re-request within the hour avoids spending the allowance. This is valuable disclosure not covered by the hints.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

The text is marred by verbatim duplication: 'URLs of another host are counted, never requested.' appears twice, and the caching sentence about the stored sample appears twice (once with cached_at). This wastes space and undermines front-loading.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

No output schema exists, and the description covers scope, sample size, caching, and allowance behavior reasonably well, but it never sketches the shape of the returned audit result, leaving the return surface largely unspecified for a tool with no output schema.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema description coverage is 100%, so url, lang, and guest_token are already documented in the schema. The description adds no parameter-level meaning beyond that, so baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

The description states a specific verb and resource with clear scope: 'Check the first 20 URLs of a site's sitemap' and enumerates what is checked (status, redirects, robots.txt, noindex, canonical, titles). It implicitly distinguishes from audit_url (single URL) via 'sitemap', but never names siblings explicitly.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

It conveys context ('The free sample of the SEO audit', 'Free, without an account'), which implies when it is appropriate, but there is no explicit when-to-use/when-not or routing to audit_url/check_domain for related needs.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.