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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It does not mention that the tool is read-only, that it makes network calls (implied by 'Open-Meteo'), or that many of the schema parameters are irrelevant to this tool's function. The description does not disclose that only the 'city' parameter is used and others are discarded, which is a significant omission.

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 brief (one sentence), which could be considered concise, but it lacks critical context. It under-specifies the tool's behavior and parameter usage, so it is not effectively structured for an agent. The brevity is not a virtue here; it results in an incomplete definition.

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 tool has 9 parameters with none required, and no output schema, the description should clarify that only 'city' is needed for the temperature function and that other parameters are irrelevant. It does not do this. An agent would be uncertain about which parameters to provide and what the return value looks like. The description is incomplete for a tool with such a broad input schema.

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 provides descriptions for all 9 parameters (100% coverage), so the schema already explains each parameter's purpose. The tool description adds no parameter-level information beyond the schema, and it does not clarify which parameters are actually relevant for the temperature lookup. Since the schema is comprehensive, the baseline is 3, but the description fails to add value or highlight the essential parameter.

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 returns the current temperature for a city via Open-Meteo, using a specific verb and resource. It is unambiguous about its primary function, but it does not differentiate from sibling tools like 'geo-hint' or other hint tools, which may offer similar geographic or weather-related capabilities.

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?

No guidance is provided on when to use this tool versus alternatives. The description only states what the tool does, not when to invoke it, nor does it mention any exclusions or conditions. An agent would not know if this is the right tool for a given weather query or if a sibling like 'geo-hint' is more appropriate.

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