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

Annotations already declare readOnlyHint=true and destructiveHint=false, so safety is covered; the description instead adds behavior the annotations cannot: where sitemap data originates, that URL and error counts are included, a hard cap of 100 results, and the paging mechanism. It doesn't discuss auth requirements or empty-result behavior, but the added behavioral context is substantial.

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?

Two dense sentences with no filler: resource and source first, then result shape, cap, and paging. Every clause carries operational information an agent needs before calling.

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?

For a two-parameter read-only list tool with no output schema, the description covers what to pass, what comes back (URL and error counts), the result cap, and how to continue paging. Nothing an agent needs in order to call it correctly is missing.

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 coverage is 100%, so the baseline would be 3, but the description goes beyond the schema by explaining that `from` should be populated with the last sitemap_id from a previous response, making the output-to-input pagination link explicit. hostId semantics are left to the schema, which already points at yandex_list_sites.

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 names the specific resource (sitemaps Yandex knows for a site) and scopes it precisely by source: robots.txt, Yandex Webmaster, or sitemap indexes. The platform-qualified framing lets an agent distinguish it from gsc_list_sitemaps and bing_list_sitemaps without opening either 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?

It gives concrete operational guidance for paging: pass the last sitemap_id as `from` to fetch the next page. It does not explicitly say when to prefer this over sibling tools such as yandex_submit_sitemap or yandex_list_sites, but the 'sitemaps Yandex knows' framing makes read-vs-submit routing fairly obvious.

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