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

No annotations are provided, so the description carries the full burden. It names Open-Meteo and implies a read-only call, but it does not state what happens with the eight non-weather parameters, whether they are ignored, what units/format the temperature is returned in, or any error/rate-limit behavior. This is a significant gap for a tool with such a broad schema.

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 clean sentence with no filler and the provider is front-loaded. However, it is arguably too terse for the complexity of the schema, so it is not a 5.

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, no annotations, nine optional parameters, and many sibling tools, a one-line description is insufficient. It does not explain why the schema includes so many unrelated fields, which parameter to supply for weather, or what a successful response looks like.

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 100%, so the baseline is 3; each parameter already has an explanation. The description adds no parameter-level detail beyond naming city, and it does not resolve the mismatch between the weather-focused purpose and the unrelated ref/feed/json/path/zone/query parameters.

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 clear resource and provider: 'Current temperature for a city via Open-Meteo.' This is specific and distinguishes the tool by subject from siblings like geo-hint, though it does not explicitly contrast itself with alternatives. The unrelated parameters in the schema slightly undermine clarity, but the core purpose is 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?

There is no when-to-use guidance, no exclusions, and no mention of alternatives. An agent can infer use for current-city-temperature queries, but with 26 siblings and an input schema containing parameters for URL normalization, JSON validation, and timezones, the description leaves the selection and invocation decision entirely to inference.

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