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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It mentions 'via Open-Meteo', implying an external network call, but does not state whether the tool is read-only, what side effects exist, rate limits, or what happens to inputs. The schema parameter descriptions mention that many inputs are 'discarded', but that is not in the tool description itself. The description is minimal and does not disclose the tool's behavior beyond the basic function, leaving significant gaps for a tool with network access.

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 that immediately states the primary purpose. It is concise and easy to scan. However, given the schema's complexity (nine parameters), the description may be too brief, omitting essential context. Still, as a concise statement, it is well-structured and efficient.

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?

The description is incomplete for a tool with nine parameters and no output schema. It does not explain the purpose of the other eight parameters, which appear to be unrelated to weather. It also does not describe the return format (e.g., temperature units, JSON structure) or any error handling. An agent cannot reliably determine how to invoke the tool correctly or interpret results without additional information. The description fails to cover the tool's full scope and expected behavior.

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?

The schema covers 100% of parameters with descriptions, so the baseline is 3. The tool description only mentions 'city' and does not add any meaning beyond what the schema already provides for any parameter. For the 'city' parameter, the schema description ('City name for a public weather hint; discarded after the call') is already informative. The tool description adds no extra semantics for any parameter, so it does not exceed the baseline.

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 verb and resource: 'Current temperature for a city via Open-Meteo.' This is specific enough to understand the core function. However, the input schema contains nine unrelated parameters (ref, url, feed, host, json, path, zone, query) that are not addressed in the description, creating ambiguity about whether the tool is solely for weather or also serves other purposes. The description does not differentiate from siblings, but the core purpose is 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 provides no guidance on when to use this tool versus alternatives. It does not mention any sibling tools or conditions under which another tool would be more appropriate. With no exclusions or context, an agent has no basis to choose this tool over others, especially given the broad parameter set that overlaps with many sibling tools (e.g., validate-json, domain-shape, etc.).

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