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

No annotations are provided, so the description carries the full burden. It only says 'via Open-Meteo', suggesting an external call, but it does not disclose that only 'city' is actually used while the other schema parameters are discarded, nor does it state the output format or that the call is read-only. The schema's parameter descriptions fill some gaps, but the description itself adds too little behavioral context.

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?

One sentence, no filler, and the key concept (city + current temperature + Open-Meteo) is front-loaded. It earns its place and avoids irrelevant details.

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 9 optional parameters and no output schema, the description is not enough. It does not clarify that most parameters are ignored, warns about any default behavior, or describe the typical return. An agent is likely to be confused why 'url' or 'path' appear on a weather tool. The description should at least say 'pass only city; other fields are ignored'.

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 description coverage is 100%: every parameter has its own description, including 'discarded' notes. The tool description does not add parameter information beyond what the schema provides. It does highlight 'city', which is the meaningful parameter, but overall this is the baseline 3 for full coverage.

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 'Current temperature for a city via Open-Meteo' names a specific verb and resource, immediately distinguishing this from siblings like geo-hint or utc-time. It is clear and unambiguous about the data source and the primary input (city).

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 other hint tools or how it relates to siblings like search options. 'Current temperature' implies use for temperature lookups, but there is no explicit when/when-not interaction and no mention of alternatives.

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