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

No annotations are provided, so the description bears full responsibility for disclosing behavior. It only states that the tool returns a temperature via Open-Meteo; it does not say whether this is a read-only network call, whether parameters other than city are ignored, what error behavior looks like, or whether any state changes occur. For an unannotated tool, this is a significant gap.

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 sentence with no filler. It front-loads the essential information—what the tool returns and for what kind of input—making it easy to scan.

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?

Despite the simple surface description, the tool has nine optional parameters, no required parameters, no annotations, and no output schema. The one-line description does not explain how to select among the many schema parameters, what the response format is, or what happens when multiple parameters are supplied. This creates significant ambiguity for an agent attempting a correct call.

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 descriptions cover all nine parameters at 100% coverage, so the baseline is 3. The tool description adds only the idea that 'city' is the relevant input, but it does not clarify how to format the city or explain that the other eight parameters are unrelated/discarded. The schema already handles the parameter documentation, so the description provides little additional semantic 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 identifies the resource ('current temperature for a city') and the data source ('Open-Meteo'), and it is distinct from sibling tools like timezone or geo-hint. It lacks an explicit action verb such as 'Get' or 'Return', and it does not acknowledge the schema's many unrelated parameters, 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?

The description implies a use case: when an agent needs the current temperature for a city. However, it provides no explicit when-to-use/when-not-to-use guidance, no exclusions, and no mention of alternative sibling tools. This is better than no guidance but still leaves the decision to inference.

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