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

There are no annotations, and the description does not disclose behavioral details such as whether the tool makes an external network call to Open-Meteo, is read-only, or can fail under certain conditions. The phrase 'via Open-Meteo' implies an external dependency, but side effects, latency, error behavior, and data freshness are not mentioned. The description carries the full burden here and does not satisfy it.

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, direct sentence with no unnecessary words. It is concise and immediately communicates the tool's main function. It does not ramble or include fluff, though the brevity leaves out important contextual details that are scored elsewhere.

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 that there is no output schema and no annotations, the description should explain what the tool returns, in what format, and under what circumstances it should be used. None of that is present. The description only covers the basic action and source, leaving the agent without essential context for successful invocation and result interpretation.

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 the schema has descriptions for all parameters, most of those descriptions are unrelated to weather or temperature, e.g., 'Git ref name; discarded after the shape check' and 'HTTPS URL to normalize or cite'. Only the 'city' parameter seems relevant, but it is not required and its relationship to the Open-Meteo call is not clarified. The description adds no meaningful semantic value beyond the already confusing schema.

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 core purpose: retrieving the current temperature for a city via Open-Meteo. It identifies the resource (city), the action (current temperature), and the data source, making the primary intent easy to grasp. It could be slightly more explicit about the exact output format, but the basic 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?

The description provides no guidance on when to use this tool versus the many sibling tools, nor does it mention any prerequisites or context for appropriate use. There is no indication of expected input requirements, such as whether a city name must be normalized or geocoded beforehand. This leaves the agent without direction on selecting this tool appropriately.

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