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

With no annotations provided, the description carries the full burden of behavioral disclosure. It names Open-Meteo as the source and indicates a current temperature result, but it does not disclose units, required inputs, behavior for unknown cities, potential errors, or return structure. The many unrelated schema parameters are also left unexplained at the description level.

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 concise sentence with no filler words. It is front-loaded and easy to parse. However, it is so terse that it omits important context, so it is good conciseness but not a model of complete structure.

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?

For a tool with nine parameters, no output schema, and no annotations, a one-line description is not complete enough for correct invocation. It does not state that city is the operative parameter, whether it is required, or what the response looks like. An agent could easily call it with no arguments or with one of the unrelated discarded fields.

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 coverage is 100%, so the baseline is 3. The description does not add parameter-level meaning beyond the schema, but the schema already documents each parameter. A slight deduction is warranted because the description only highlights 'city' while the schema exposes eight other optional parameters, which creates ambiguity about what an agent should actually pass.

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 resource: current temperature for a city, with the data source specified as Open-Meteo. It is easy to identify as the weather-related tool among the siblings. However, it lacks an explicit verb like 'gets' or 'returns,' making it slightly less direct than ideal.

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 alternatives, nor does it mention that a city is needed. There are no preconditions, exclusions, or examples. The phrase 'for a city' implies a use case, but it is not explicit enough for an agent to know how to distinguish this from related hint tools.

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