uk_postcode_nearest

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

No annotations exist, so the description carries the full burden. It usefully discloses the data source and that it is keyless (no auth needed), but says nothing about return format, how ties/distance are computed, rate limits, or what happens for coordinates outside the UK.

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?

Two compact sentences, front-loaded with the operation and followed by the source detail. Nothing extraneous.

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?

For a tool with no annotations, no output schema, and 0% parameter coverage, the description is too thin: it omits the meaning of 'limit', the shape of the result, and coverage limits. It is adequate to guess the call but not to invoke it confidently.

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 conveys the meaning of latitude/longitude, but the 'limit' parameter (its default and max) is entirely undocumented in both the schema and description, leaving a real gap for a 3-param tool.

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?

States a specific verb and resource ('Find UK postcodes nearest to a latitude/longitude') with the input domain made explicit. This clearly distinguishes it from the sibling uk_postcode_lookup, which implies lookup by known postcode rather than reverse geocoding.

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?

Gives no guidance on when to use this versus uk_postcode_lookup, nor any exclusions (e.g. UK-only coverage, non-UK coordinates). The 'nearest' wording implies a use case but nothing is stated about alternatives.

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