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

With no annotations, the description carries the full burden, but it only adds 'via Open-Meteo' as a behavioral hint. It does not disclose whether the call is read-only, how errors are handled, what units are returned, or that other schema parameters are irrelevant.

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 with no filler. It communicates the core purpose immediately and efficiently.

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?

Without an output schema or annotations, the description should provide enough context to invoke the tool correctly, but it leaves out return format, units, and which parameter among the nine optional ones to use. The large unrelated parameter set makes this gap more serious.

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's 'for a city' correctly points to the city parameter, but it adds no format, requiredness, or clarification about the other eight optional parameters in the schema.

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 the tool returns 'Current temperature for a city via Open-Meteo,' which names the resource (city) and the domain (weather), setting it apart from siblings like geo-hint. It lacks an explicit verb such as 'get' and does not mention the unrelated schema parameters, so it is clear but not maximally precise.

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 implies usage: call this when you need the current temperature for a city. It gives no explicit when-to-use or when-not-to-use guidance and names no alternative tools or conditions, so an agent must infer the context.

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