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

With no annotations, the description carries some burden, and 'via Open-Meteo' at least signals an external read-only lookup. However, it does not disclose the relationship between the nine optional schema parameters and the actual weather behavior, nor mention side effects, output format, or that most inputs are ignored.

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, immediately legible sentence with no filler. The core purpose is front-loaded and the external source is named.

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 simple data-retrieval hint, the description states what the tool returns, but the 9 optional parameters and the lack of an output schema leave ambiguity about how to actually invoke the tool and interpret the result. The description does not explain that the city parameter is the relevant one or what the output shape/units will be.

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% and every parameter has a description, so the baseline is 3. The description itself only adds meaning for the `city` parameter; it does not compensate for the confusing presence of unrelated parameters like ref, url, or json.

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 names a specific verb-resource pair ('Current temperature for a city') and a specific data source (Open-Meteo). It is easily contrasted with sibling tools like geo-hint or timezone, so an agent can tell it apart without inspecting the schema.

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 about when to reach for this tool compared to alternatives, no exclusions, and no mention of preconditions. It is only a bare statement of purpose.

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