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

With no annotations, the description carries the full behavioral burden, but it only says 'via Open-Meteo.' It does not disclose that this is a stateless read, that other parameters are ignored, whether an API key or network access is needed, or what happens for unknown cities. The schema's 'discarded' notes hint at side-effect-free behavior, but the tool description itself does not.

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 compact sentence with no filler and the core action front-loaded. There is no wasted text.

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?

A nine-parameter tool with no annotations and no output schema needs more context than this. The description does not say which parameter to use, what unit the temperature is returned in, what errors look like, or that the other parameters are irrelevant. The agent can guess, but the tool definition does not fully equip it.

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 description need not explain each parameter. It does not add meaning beyond the schema; the city parameter is already described in the schema. The description's phrase 'for a city' overlaps with schema info but does not clarify the role of the other eight optional fields.

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 states a clear outcome: current temperature for a city, and names the data source (Open-Meteo). It is easy to tell apart from sibling geo-hint/timezone tools. It loses a point for using a noun phrase rather than an explicit verb like 'gets' and for not acknowledging that only the city parameter matters.

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 when-to-use or when-not-to-use guidance is provided. There are no explicit alternatives or exclusions, and the description does not warn that only 'city' is relevant among the nine optional schema parameters. Usage context is left entirely to inference.

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