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

With no annotations, the description carries full responsibility for behavioral disclosure. It only states the output is 'current temperature' but doesn't mention side effects, rate limits, authentication needs, or the fact that most parameters are 'discarded' as indicated in the schema. The schema's 'discarded' notes are not part of the description, so the agent is left uninformed about the tool's actual behavior.

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 concise sentence, which is efficient. However, it omits essential information about the tool's multi-purpose nature and the range of parameters. Conciseness is not an issue, but the description under-specifies to the point of being unhelpful for the broader tool.

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 tool with 9 parameters, none required, no output schema, and no annotations, the description is severely inadequate. It only covers the weather use case, leaving the purpose of the other parameters and the tool's overall behavior unexplained. An agent cannot correctly select or invoke this tool for anything beyond a simple weather query.

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 description adds no meaning beyond the schema. It implicitly references 'city' but does not explain the other 8 parameters, which are all documented in the schema. Since schema coverage is 100%, the baseline is 3, but the description is misleading by implying weather is the sole function. It fails to clarify how the other parameters are used, so it does not help the agent understand the full parameter set.

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 specific purpose: current temperature for a city via Open-Meteo. However, the input schema includes 8 other parameters (ref, url, feed, host, json, path, zone, query) that are unrelated to weather, suggesting the tool is actually multi-purpose. The description only covers the city/weather use case and omits the broader scope, making the tool's purpose ambiguous.

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?

No guidance is given on when to use this tool versus alternatives like geo-hint or lib-docs-hint. The description doesn't mention exclusions, preconditions, or scenarios where a different tool would be appropriate. An agent cannot determine when to invoke this tool beyond the narrow weather hint case.

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