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

Annotations already declare readOnlyHint=true and destructiveHint=false, so the tool's safety profile is covered. The description adds behavioral context beyond annotations: it explains that for cities it 'searches all airports in that city' and returns kgmid, which is not in the schema. It also discloses the output format. This enriches the behavioral picture, though it could mention potential multiple results or no-match scenarios.

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 well-structured with a bulleted list of return types, a clear required-parameter note, and a usage tip. It is concise, front-loads the purpose, and every sentence adds value. The note about common IATA codes is a useful addition without bloating the text.

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 must explain return formats, which it does (IATA and kgmid). It also clarifies the required parameter and provides a usage example. For a simple two-parameter search tool, this is largely complete, though it doesn't cover edge cases like multiple matches or empty results. The overall complexity is low, so this is sufficient.

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 schema description coverage is 100%, so both parameters (q and search_type) are already documented in the input schema. The description adds an example for q and clarifies the output behavior for cities, but these are largely redundant with the schema descriptions. The note about common IATA codes is a usage guideline rather than parameter semantics, so the description adds marginal value beyond the schema.

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 clearly states the tool searches for airports and cities to return identifiers for Google Flights tools. It specifies the exact outputs (IATA codes for airports, kgmid for cities) and gives concrete examples, making its purpose unmistakable and distinct from the sibling flight tools that consume these identifiers.

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 explicitly says when to use the tool: 'when you have a city name like 'New York' or 'Paris' and need to convert it to codes that the flight tools accept.' It also provides an exclusion by noting that common IATA codes like JFK can be used directly without this tool, giving clear guidance on alternatives.

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