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

Annotations already declare readOnly/idempotent/non-destructive/non-open-world, so the safety bar is covered. The description adds useful behavior beyond that: the URL pattern /{country}/{vertical}/{slug}/, the enumerated response languages, and that record counts are returned.

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?

One front-loaded sentence carries the core payload, with a short illustrative tail sentence. Efficient, though the parenthetical language list and the trailing example add slight bulk.

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 zero-parameter, no-output-schema catalog tool, the description fully covers the return shape (verticals, countries, languages, filters, URL pattern, record counts). Nothing needed 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?

The tool takes zero parameters, so the baseline is 4. The description correctly implies no filtering is needed to call it, and mentions the filters exposed on the listed resources rather than inventing inputs.

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 (Lists) and resources (verticals, countries, response languages), and immediately distinguishes itself from siblings like search_entities/get_hotel by being a discovery/catalog endpoint. An agent can tell what this returns 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?

The example ('Today: hotels in Andorra') implies this is the entry point for discovering what data exists, but there is no explicit when-to-use vs alternatives guidance or any exclusion rules. Usage is inferred rather than stated.

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