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

With no annotations provided, the description carries the full burden of disclosing behavior. It only mentions that the tool uses Open-Meteo, hinting at an external API call, but fails to disclose side effects, data retention (e.g., parameters are discarded), or any limitations. The schema descriptions provide some clarity on discard behavior, but the description itself is silent, leaving the agent uninformed about operational traits.

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 waste, which is good. However, it is so brief that it fails to convey the tool's actual versatility, making it under-specified. While conciseness is appreciated, the lack of structured information about the other parameters reduces its effectiveness. A slightly longer description with clear usage would be more appropriate given the complexity.

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's complexity (9 parameters, no required fields, no output schema), the description is severely incomplete. It only covers the weather use case, ignoring the other parameters that likely enable distinct functions (e.g., URL normalization, JSON validation, timezone checks). Without explaining these, an agent cannot correctly determine when to invoke the tool for those tasks. The lack of output schema and minimal description leaves key operational details missing.

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%, so the baseline is 3. The description adds minimal value by naming 'city' as the key parameter, but this is already documented in the schema. It provides no extra context for the other eight parameters, which remain unexplained in the description, nor does it clarify the tool's multi-functional nature.

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 primary function: returning the current temperature for a city via Open-Meteo. It specifies a verb (retrieve) and resource (temperature), which sets clear expectations. However, it does not mention the other eight parameters, suggesting the tool may serve additional purposes, which creates ambiguity about its full scope.

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 given on when to use this tool versus alternatives. The description does not mention any exclusions, conditions, or sibling tools. An agent cannot infer whether to prefer this over similar tools like geo-hint or timezone, or when to invoke it for non-weather parameters.

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