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

Annotations already declare read-only, open-world, non-destructive. The description goes further by disclosing behavior not in the annotations: it fetches from robots.txt and standard paths, follows index files, performs a status spot-check (which explains the idempotentHint=false), and issues a pass/warn/fail verdict. This meaningfully augments the safety profile.

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?

A single dense sentence that front-loads the action and then lists return contents; every clause carries information about what is fetched or returned. It is long but not padded, though slightly list-heavy.

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?

With no output schema, the description compensates by enumerating the key return fields (URLs with lastmod, staleness summary, foreign-host URLs, status spot-check, verdict). For a no-crawl, read-only tool this is close to complete, with only minor gaps around output size limits already covered by the 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 all four parameters are already documented (detail, domain, max_urls, status_sample). The description only loosely echoes the status spot-check and full-URL return, adding little beyond the schema. Baseline 3 is appropriate.

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?

States a specific verb+resource (fetch a domain's sitemaps) and precisely scopes it: robots.txt Sitemap lines plus standard paths, index files followed. It also enumerates the return payload, so an agent can distinguish it from siblings like get_gsc_sitemaps and submit_sitemap without opening a schema.

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?

"Any public domain, no crawl" gives a clear usage condition and clarifies it does not crawl pages, implicitly separating it from crawl tools like start_crawl. It does not, however, explicitly name alternatives such as robots_check or get_gsc_sitemaps for the overlapping discovery use cases.

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