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

With no annotations present, the description carries the full burden of behavioral disclosure. It only mentions 'via Open-Meteo', implying an external call, but does not disclose rate limits, caching, privacy, or that the city parameter is discarded. The schema notes 'discarded after the call', but the description itself offers no such detail.

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 eight-word sentence with no filler. The subject is front-loaded, and every word contributes to conveying the tool's purpose. It is appropriately sized for its minimal scope.

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 lacks essential context for an agent to invoke the tool correctly. There is no output schema, no stated return value format (e.g., units), and no clarification of how to handle the extraneous schema parameters. For a tool with a confusing input schema and no annotations, this is insufficient.

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 includes seven parameters, but the description only references the city concept. Schema coverage is low (~14%), and the description does not clarify that only 'city' is relevant or that other parameters are ignored. The schema already documents 'city' well, but the description fails to compensate for the ambiguity introduced by the unrelated parameters.

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 resource (city) and data source (Open-Meteo), making the tool's core function understandable. However, it lacks an explicit verb (e.g., 'Gets') and does not differentiate from sibling tools, though no other weather-specific sibling exists.

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 exclusions, preferred contexts, or relationships to siblings like geo-hint or lib-docs-hint. Usage context is only implied by the tool name and description.

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