get_air_index

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

With no annotations provided, the description carries the full burden of behavioral disclosure. It clearly explains the aggregation behavior and lists the categories, but it does not mention whether the call is read-only, if it requires authentication, how the index is computed (e.g., current vs. cached), or what the response structure contains beyond the category. The description implicitly suggests a read operation via 'get,' but lacks explicit behavioral context.

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 a single, tightly written sentence that front-loads the core purpose ('Get the composite air-quality index') and immediately specifies the aggregation and category levels. There is no extraneous information, making it efficient and scannable.

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 one parameter and no output schema, the description explains what the tool produces (a category) but stops short of describing the exact response format—whether it returns just the category label, a numeric value, or both. It also omits any caveats like error conditions or station validity. Given the low complexity, this is a minor gap, so a 3 is appropriate.

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 description covers the only parameter (station_id) at 100% with 'Numeric station ID.' The tool description adds no additional meaning about the parameter—it does not explain how station_id is used or validated. Per the calibration rule, when schema coverage is high, the baseline is 3, and the description does not elevate it.

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 specifies a precise verb ('get') and resource ('composite air-quality index for a station'), and clearly distinguishes itself from siblings like get_sensor_readings by focusing on the aggregated index rather than raw data. The phrase 'aggregates all pollutants into a single category' makes the tool's purpose unambiguous.

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?

The description gives no explicit guidance on when to use this tool versus alternatives. With sibling tools like get_sensor_readings, it would be helpful to state 'Use this for the overall index; use get_sensor_readings for individual pollutant values.' No such direction is provided, leaving the agent to infer from the name alone.

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