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

With no annotations, the description must carry the transparency burden, but it only states the basic purpose. It does not disclose that the 'city' parameter is effectively required, what happens with the other eight parameters, whether network access is involved, or what errors may occur. The schema's unrelated optional parameters make behavior even more opaque.

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, concise sentence that is front-loaded with the tool's core purpose. It contains no fluff or redundant wording.

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?

Given the complex and inconsistent schema with nine optional parameters and no output schema, the description is far too sparse. It does not explain the expected input (city), the output format (temperature units, current vs. forecast), or the role of the extra parameters, leaving an agent without enough context to use the tool 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?

Although schema coverage is 100%, the parameter descriptions are confusing and largely irrelevant to weather. Only 'city' aligns with the stated purpose, and its description ('discarded after the call') is odd. The remaining parameters (ref, url, feed, host, json, path, zone, query) have no clear connection to fetching a current temperature, and no guidance indicates which parameters should be 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 clearly states the tool's purpose: 'Current temperature for a city via Open-Meteo.' It identifies a specific resource and data source, though it does not mention sibling tools or explicitly differentiate itself from related tools like geo-hint or web-fetch.

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 guidance on when to use this tool versus alternatives. The description does not mention prerequisites, such as needing a city name, or situations where another tool might be more appropriate.

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