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

Annotations already mark the tool read-only, idempotent, and non-destructive, so the safety profile is covered. The description adds that this is an edition-scoped metadata call and a precursor to querying, but it does not disclose additional behavioral details such as caching, freshness, or response size. No contradiction with annotations.

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 sentences with no filler: the first front-loads the complete resource list, and the second provides the usage context. Every phrase earns its place.

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?

Given no parameters, an existing output schema, and read-only annotations, the description supplies the only missing context: what the tool returns and when to call it. The definition is complete for a simple directory/discovery tool.

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 has zero parameters, so there is no parameter documentation burden for the description to carry. With 100% schema coverage and an empty schema, the baseline of 4 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?

The description names a specific operation and resource: it gets dataset version, source dates, licence, coverage counts, endpoint URLs, filter vocabularies, and country metadata. It also differentiates from sibling retrieval tools by positioning itself as the slug-discovery entry point before querying.

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?

'Use this to discover supported country, class, ownership, region and continent slugs before querying' is an explicit when-to-use instruction. It does not name alternatives or exclusions, but among the siblings it is the clear directory/discovery tool, so the guidance is strong albeit not fully exhaustive.

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