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

The annotations already mark this as read-only, idempotent, and non-destructive. The description adds detailed behavioral traits: the matching order (exact diacritic-folded alias matches first, then trigram-fuzzy), the presence of similarity scores and containment hierarchy, and the semantic meaning of an empty response. This goes beyond annotations, providing valuable context.

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?

The description is three sentences, front-loaded with an immediate summary ('Travel gazetteer lookup'), and each sentence adds distinct information: scope, matching logic, and response interpretation. No filler words.

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?

The tool has no output schema, so the description must explain the return values. It states candidates carry geo_ids, similarity scores, and containment hierarchy, and explicitly covers the empty-list case. This is sufficient for the agent to understand both input and output behavior.

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 input schema has 0% description coverage for two parameters. The description explicitly characterizes 'text' as 'free-text place name', which adds meaning. However, it never mentions the 'limit' parameter or explains how it controls the number of candidates. This leaves a gap in parameter understanding.

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 begins with 'Travel gazetteer lookup' and clearly states that it maps free-text place names to candidate geo_ids. It specifies the scope (43k-entity gazetteer with admin divisions, cities, airports/IATA, stations) and differentiates from sibling tools as a resolver for the other travel-vertical tools.

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 states this is for 'the other travel-vertical tools', indicating when it should be used. It also clarifies that an empty candidates list means no match, not an error, which is a usage interpretation. However, it doesn't explicitly name alternative tools or explicitly say when not to use it, so it gets a 4.

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