airquality_stationsFind air quality monitoring stations that are reporting now, near a place or across a country: name, operator, reference-grade flag, coordinates, distance, pollutants measured and last reading time. Costs $0.002 USDC per call (x402).
| Name | Required | Description | Default |
|---|---|---|---|
| lat | No | ||
| lon | No | ||
| near | No | Place name | |
| limit | No | ||
| country | No | 2-letter ISO code instead of near | |
| parameter | No | Only stations measuring this, e.g. pm25 |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already cover the safety profile (readOnlyHint, openWorldHint), but the description adds genuinely non-structured context: the call is metered at $0.002 USDC via x402, and results are limited to stations currently reporting. Missing are rate limits, pagination, and what happens when lat/lon are combined with near/country.
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?
One front-loaded sentence opening with the verb and resource, then a compact field list and a cost sentence. Nothing is padded, though the nine-item output enumeration is longer than strictly necessary to route a call.
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 correctly compensates by listing the returned attributes, and it discloses cost. However, for a 6-parameter tool with zero required parameters, it never explains the default behavior when no location or country is supplied, nor limit/pagination semantics — meaningful gaps.
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 coverage is only 50% (lat, lon and limit have no descriptions). The description partially compensates by naming the two location modes (a place vs a country) and by relating the returned fields to the filter intent, but it says nothing about lat/lon pairing, limit/default behavior, or the parameter filter. Baseline 3 for partial compensation.
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?
Specific verb+resource+scope: 'Find air quality monitoring stations that are reporting now, near a place or across a country.' It also enumerates the returned fields, so an agent knows what it gets. It does not, however, differentiate itself from close siblings like 'airquality', 'airquality_compare' or 'airquality_history', leaving the agent to guess which one to pick.
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?
'Reporting now' and 'near a place or across a country' imply the two usage modes (location-scoped vs country-wide), which is useful. But there is no explicit when-to-use vs when-not, and no mention of when a sibling like airquality_history or airquality would be the better choice; the agent must infer from the field list.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
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