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

Annotations already declare readOnlyHint=true and openWorldHint=false, so safety is covered. The description adds useful behavioral detail beyond that -- it returns latest readings plus AQI, sorted nearest first -- but says nothing about how many monitors are returned, how radius affects results, or rate limits.

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 compact sentence that front-loads the core resource and then lists returned fields and ordering. Nothing is wasted, though the pollutant enumeration consumes space that could have gone to parameter or scope detail.

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 no output schema, the description helpfully names the return fields and ordering. However, for a geospatial query tool it omits result-count limits and the meaning of radius_km, so an agent cannot fully predict the call's behavior from the definition.

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% for three parameters, so the description must carry the burden and largely does not. 'Near a point' weakly implies lat/lon, but radius_km is never mentioned, nor its units, default (25 km), or 500 km cap, leaving the key search-scope parameter semantically unexplained.

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 names a specific verb-resource pair ('Air quality monitors near a point') and enumerates the returned measurements (PM2.5, PM10, O3, NO2, SO2, CO, AQI). The words 'near a point' distinguish it from a general air-quality sibling such as sensors_air, though no sibling is named explicitly.

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 statement of when to use this versus alternatives like sensors_air or sensors_stations_near, and no prerequisites or exclusions. Usage is only implied by the geospatial phrasing 'near a point'.

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