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

With no annotations provided, the description carries the burden. It discloses the input format, the lack of need for coordinates, and the free pricing model, plus points to the paid API. It does not detail rate limits, data freshness, or error behavior, but for a simple lookup this is sufficient.

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 two sentences, front-loaded with core functionality, and includes only relevant extras (free, paid API pointer). No wasted words.

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 single-parameter lookup tool without an output schema, the description enumerates the return values (pollutants, AQI, band) and explains input expectations. It is sufficiently complete for an agent to invoke correctly.

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?

The schema already documents the location parameter with an example. The description adds context by stating no coordinates are needed, clarifying the expected input format beyond the schema. This is a meaningful addition, but not extensive.

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 the tool returns current air quality data for a place, listing specific pollutants and AQI metrics. It also differentiates from siblings by noting it requires no coordinates, making its purpose distinct from geocoding tools.

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?

It provides context that a place name is sufficient and that the tool is free, directing users to paid_catalogue for paid API alternatives. However, it does not explicitly contrast with other sibling tools or specify when not to use this tool.

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