unlocode_lookup

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

Annotations indicate readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds context by stating the dataset size (116,129 locations) and explaining the UN/LOCODE format (5-character code). No contradiction. Does not mention rate limits, but that is acceptable for a lookup tool.

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 concise and well-structured: a one-sentence summary, then explanation of the code format, then bulleted use cases. Every sentence adds value, no fluff.

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 is simple with no output schema, but the description covers all necessary context: what UN/LOCODE is, how to search, and available filters. Complete for a lookup 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?

Schema description coverage is 100%; each parameter has a clear description. The tool's description reinforces the function parameter's values (port, airport, etc.) but adds little beyond schema. Baseline 3 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 clearly states the tool's purpose: 'Search 116,129 UN/LOCODE transport locations worldwide.' It explains what UN/LOCODE identifies and gives examples (GBLHR, NLRTM). This distinguishes it from sibling tools like airline_lookup or container_lookup.

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 lists when to use the tool: to find a port/airport/terminal by name, look up a specific UN/LOCODE, or filter by country/function. This provides clear guidance and implies when not to use it (e.g., for other transport codes).

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