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

No annotations are provided, so the description carries full responsibility for disclosing behavior. It only states that it fetches temperature via Open-Meteo; it does not mention that other parameters are discarded, whether it performs network requests, what happens with invalid city names, rate limits, or the return format. The schema descriptions for parameters like 'discarded after the shape check' are not reflected in the tool description, leaving significant behavioral gaps.

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 extremely short (one sentence), which is concise, but it is under-specified rather than effectively concise. It lacks critical context about the tool's actual scope, the meaning of the other parameters, and any usage boundaries. The information provided is front-loaded but insufficient for safe invocation.

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 9 parameters, no output schema, and no annotations, the description must fully explain the tool's behavior. It only covers the weather use case and ignores the other parameters entirely. There is no mention of return values, error conditions, or how the tool handles non-weather inputs. This is completely inadequate for an agent to correctly use the tool for any input other than a city name.

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?

The schema covers 100% of parameters with descriptions, so the baseline is 3. The tool description does not add any meaning beyond the schema; it only highlights 'city' implicitly. It fails to clarify the role of the other 8 parameters, which are described in the schema as checks or discards. This omission could confuse an agent, but since the schema itself documents each parameter, the description does not subtract value.

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 a specific action (get current temperature) for a specific resource (a city) and names the data source (Open-Meteo). However, it does not account for the 9 input parameters in the schema, many of which (ref, url, feed, host, json, path, zone, query) appear unrelated to weather. This ambiguity between the stated purpose and the schema reduces clarity, but the core purpose is still communicated.

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 gives no guidance on when to use this tool versus alternatives or any exclusions. It does not mention that the tool may be intended for a broader set of 'hint' functions or that only the 'city' parameter is relevant for weather. An agent would not know if it should call this tool for non-weather inputs or when another sibling tool is more appropriate.

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