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

Annotations already declare readOnlyHint=true, idempotentHint=true, openWorldHint=false and destructiveHint=false, so the safety profile is fully covered. The description usefully adds that results are aggregated with stay counts, but says nothing about ordering, pagination, or completeness of the result set beyond that.

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 that lead with what is returned and close with the actionable link to search_stays. Slightly convoluted opening clause ('The countries and destinations that have stays') but no wasted filler.

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 an output schema present, the description does not need to enumerate return fields, and the sole parameter is fully documented in the schema. What remains is conveyed: what is listed, that counts are included, and how the output feeds search_stays.

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% and the single 'country' parameter is documented there (name or ISO code). The description never mentions the country filter, so it adds no meaning beyond the schema; 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 names the resources precisely: countries/destinations that have stays plus the collections (Coast, City, Mountain), each with a stay count. This separates it from the singular get_destination and from search_stays, though the listing verb itself is only implied by the name rather than stated.

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?

The closing line 'Their names and slugs are the filters of search_stays' tells the agent exactly why and when to call this: to discover valid filter values before searching. No explicit exclusions are given, but the workflow context is clear.

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