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

No annotations are provided, so the description carries the full behavioral disclosure burden. It names Open-Meteo, which implies an external network call, but it does not state that the call is read-only, which parameters are actually used, what happens when extra parameters are supplied, or what the response looks like. The schema's 'discarded' notes are not integrated into the description.

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 sentence with no filler: 'Current temperature for a city via Open-Meteo.' It is front-loaded with the tool's purpose and immediately communicates the essential domain.

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?

This is a 9-parameter tool with no output schema and no annotations, so the description needs to supply more context. It fails to state that only 'city' should generally be supplied, what temperature units are returned, or what happens for invalid or unknown cities. The presence of many unrelated optional parameters makes the missing guidance more damaging.

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 some value by highlighting 'city' as the key input, but it does not clarify the role of the other eight optional parameters. The schema descriptions for those parameters say they are 'discarded' after checks, which is ambiguous for an agent deciding how to call this tool.

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 via Open-Meteo. It names the resource (city), the data (current temperature), and the source. It does not use an explicit verb like 'gets', and it does not actively distinguish itself from siblings, but the weather focus makes the purpose clear.

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 when to use the tool: when a current city temperature is needed. However, it gives no explicit guidance about which parameters are meaningful, especially because the schema has eight other optional parameters that appear irrelevant. It also does not mention alternatives or exclusions.

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