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

Annotations already declare readOnlyHint=true and openWorldHint=false, so the safety profile is covered. The description adds genuine behavior beyond that: results span all open networks, are ordered by distance, and each carries distance and parameter data. It does not disclose result limits, pagination, or how filters combine, which is meaningful for a 'nearest first' list.

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 dense sentence with the scope front-loaded and no filler. It reads as a fragment without a leading verb, but every clause (networks, proximity, ordering, return fields) 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?

With five parameters, 40% schema coverage, and no output schema, the description should do more. It hints at the return shape (distance plus parameters, sorted nearest first) but leaves open what a station object contains, whether results are capped, and how radius interacts with the network filter.

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%, but the enum-like values for network and parameter are already spelled out in the schema, and lat/lon are self-evident. The description contributes a little by tying 'parameters' to the returned stations, but it says nothing about radius_km's units, default, bounds, or the semantics of passing null filters, so it does not fully compensate for the coverage gap.

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 gives a specific resource (stations across every open sensor network) with a spatial scope ('near a point') and ordering ('nearest first'). It is clear what the tool returns, but it does not distinguish itself from plausible siblings such as sensors_air_near or weather_stations_near, so the agent must infer the difference.

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?

There is no explicit when-to-use statement, no exclusions, and no named alternative. The only guidance is implicit in 'near a point', leaving the agent to guess whether this discovery tool should precede sensors_air_near or sensors_water_gauge calls.

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