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

With no annotations, the description carries the full burden of behavioral disclosure. It only says it returns current temperature via Open-Meteo, but fails to disclose that most of the 9 input parameters are discarded (as indicated by schema descriptions) and that only 'city' is relevant. It also doesn't mention whether this is a real API call, a cached hint, or a stub, nor any side effects or rate limits. The word 'hint' suggests a lightweight response, but that is not clarified.

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, front-loaded sentence, which is efficient in structure. However, it is under-specified to the point of being terse, omitting essential context about parameter usage and behavioral details. While it is concise, it does not earn its brevity by covering the necessary information; it sacrifices completeness for brevity.

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 and a simple weather purpose, the description is incomplete. It does not clarify which parameter to use, that all others are ignored, or what the output format looks like (no output schema). For a tool that appears to be a simple temperature check, the description should at least mention that only the 'city' parameter matters and what the return value is. This is a significant gap.

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 has 100% description coverage, with each parameter documented, including notes that many are 'discarded'. The tool description adds the explicit connection between the city parameter and the weather lookup, which is useful. However, it does not add significant meaning beyond the schema, such as the format for the city name or how the temperature is returned. The description adds minimal value over the schema's own descriptions.

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 function: retrieving current temperature for a city via Open-Meteo. It uses a specific verb ('current temperature') and identifies the resource (city) and service. It distinguishes from siblings implicitly by naming the weather domain, though it doesn't explicitly contrast with any other tool.

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. It does not mention that it's a lightweight 'hint' (as opposed to a full weather service), nor does it state any prerequisites or exclusions. The description leaves the agent to infer that it is for current temperature checks, but gives no context on when not to use it.

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