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

There are no annotations, so the description carries the full behavioral burden. 'Current temperature for a city via Open-Meteo' suggests a read-only external lookup, but it does not disclose error behavior on unknown cities, network dependency, response content, or whether the temperature returned has any unit/format guarantees. This is a meaningful transparency gap.

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 one short, front-loaded sentence with no filler. Every word contributes to identifying what the tool does and the data source.

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 9 optional parameters, no annotations, and no output schema, a one-sentence description is not enough. The agent is left without clarity on what the function returns, what happens when extraneous inputs are supplied, how the tool handles missing optional parameters, or what constraints apply to successful invocation.

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 even though the tool description itself only mentions the city concept. The full 9-parameter schema is self-documenting, but the description does not explain why the other optional parameters exist or which are relevant to a weather lookup.

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 identifies the tool as returning current temperature for a city through Open-Meteo. It is distinct enough from siblings such as geo-hint and timezone to discriminate, though it lacks an explicit verb such as 'fetches' or 'returns'.

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 the tool should be used when a caller wants current weather for a city, but it gives no guidance about when not to use it or how it relates to alternatives like web-fetch, geo-hint, or browser-url-ok. No if/then or when-to-use/when-not-to-use guidance is present.

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