unlocode_lookup

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

Annotations already declare readOnlyHint=true, destructiveHint=false, idempotentHint=true. The description adds context about the data set size (116,129 locations) and code structure, but does not disclose any behavioral traits such as rate limits, authentication needs, or what happens on no results.

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: a concise intro, a brief explanation of the code format, and a bulleted use-case list. Every sentence adds value, no fluff or redundancy.

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 5 optional parameters and no output schema, but the description covers the purpose, code format, and filtering options. It does not mention the response format or pagination behavior (though limit parameter hints at it). Very good, but could mention the expected return structure.

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%, so the baseline is 3. The description adds value by explaining the UN/LOCODE format (2-letter country + 3-character location) and listing the possible function values, which goes slightly beyond the schema's brief descriptions.

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 'Search 116,129 UN/LOCODE transport locations worldwide' with a specific verb and resource. It distinguishes UN/LOCODE as a 5-character code for ports, airports, etc., which differentiates 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 three use cases: find port by name, look up a specific code, filter by country or function. It provides clear context for when to use the tool, but does not explicitly state when not to use it or mention alternatives among siblings.

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