Current temperature, wind, precipitation and weather code plus a 3-day daily forecast, by city name or latitude/longitude. 0.002 USDC per call via x402.
| Name | Required | Description | Default |
|---|---|---|---|
| lat | No | ||
| lon | No | ||
| place | No | City name, e.g. Zagreb | |
| paymentProof | No | Payment proof: USDC tx hash on Polygon or Base (0x...) or Solana tx signature. Omit on the first call to receive the 402 payment instructions, pay, then call again with the proof. |
Changes observed during successful MCP inspections.
Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
With no annotations, the description carries the full behavioral burden. It usefully discloses the returned weather fields, forecast horizon, and x402 payment model, but it omits units, error behavior, and any rate or permission constraints beyond the per-call cost.
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 front-loaded sentences with no wasted words. It first states what is returned, then the input modes, then the cost mechanism.
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?
There is no output schema, so the description appropriately lists the returned data fields and forecast length. The payment flow is partially covered by the paymentProof parameter description, and the remaining gaps, such as units and lat/lon pairing rules, are minor for a weather lookup tool.
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 50%, with place and paymentProof documented in the schema, while lat and lon have no schema descriptions. The description partially compensates by saying inputs can be a city name or latitude/longitude, but it does not clarify whether lat and lon must be supplied together or how precedence works if place is also provided.
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 states a specific resource and return set: current temperature, wind, precipitation, weather code, and a 3-day daily forecast. It also distinguishes the accepted input modes, city name or latitude/longitude, so an agent can identify the tool unambiguously.
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 clearly indicates the two supported ways to invoke the tool: by city name or by latitude/longitude. It also states the cost and payment mechanism, but does not explicitly describe edge cases or how to choose between place and lat/lon if both are available.
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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