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

Annotations already cover the safety profile (readOnlyHint, idempotentHint, destructiveHint=false, openWorldHint=false), so the bar is lower. The description adds useful context the annotations do not: results are distance-annotated in metres and the dataset is curated rather than exhaustive. It does not disclose ordering, result fields, or pagination behavior.

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?

A single tightly written sentence with the output unit front-loaded at the end and zero filler. Every clause carries information.

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 read-only spatial query with no output schema, the description tells the agent the key return fact (distance in metres) and the input coordinate standard. Ordering, default radius/limit behavior, and returned fields are left to the schema, which is acceptable given its parameter-level defaults.

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 only 40% (latitude and longitude have no descriptions at all), so the description must compensate. It helps by specifying the WGS84 coordinate system for lat/long, but says nothing about limit, radius, or the category enum beyond what the schema already documents.

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+resource (find nearest curated Chelsea places) with spatial scope and the unit of the result (metres). It is distinguishable from get_place (single lookup) and list_places (listing), though it never names those siblings to sharpen the contrast.

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?

Usage is only implied: 'to a WGS84 coordinate supplied in the request' hints that coordinates are required input, and the nearby framing suggests a spatial-proximity use case. There is no explicit when-to-use, no when-not-to-use, and no routing to get_place or list_places for non-spatial lookups.

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