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

Beyond the readOnly/idempotent annotations, the description discloses matching order (exact diacritic-folded aliases first, then trigram-fuzzy), similarity scores, containment hierarchy for homonym disambiguation, and the meaning of an empty candidate list. This is strong behavioral transparency.

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?

Three dense sentences, each earning its place: what the tool does, how matching works, and how to interpret an empty result. Information is front-loaded and there is no 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 no output schema, the description still explains the return shape: candidate geo_ids, similarity scores, containment hierarchy, and the empty-list case. Combined with annotations covering safety and idempotency, this is complete enough for an agent to call it correctly.

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 0%, so the description must compensate. It clearly defines 'text' as a free-text place name and explains the output candidates, but it does not explicitly describe the 'limit' parameter's behavior or how it affects results.

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?

Description states a specific verb ('lookup') and resource ('travel gazetteer'), maps free-text place names to candidate geo_ids, and ties it to other travel-vertical tools. This clearly differentiates it from siblings like search or get_entity.

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 description gives clear context: use this when you have a free-text place name and need geo_ids for travel-vertical tools. It does not explicitly name alternatives or when-not-to-use cases, but the intended use is evident.

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