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

With no annotations provided, the description carries the full burden of explaining side effects, network usage, or read-only behavior. It implies a read-only weather lookup but does not explicitly disclose that it makes an external API call or that all other parameters are ignored.

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, short sentence that conveys the core functionality without any fluff. It is appropriately sized and front-loaded with the main action.

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 any output schema, usage examples, or instructions on which parameter is required. Given the confusing schema with many discarded parameters, an agent has no way to know how to correctly invoke this tool.

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 nine parameters, all optional, with descriptions that are largely irrelevant or contradictory to the tool's purpose. For example, the 'city' parameter is described as 'discarded after the call,' which directly conflicts with the tool's stated function. The descriptions provide no useful guidance for selecting or filling 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 clearly states the tool returns the current temperature for a city using Open-Meteo, which is a specific verb and resource. However, it does not distinguish this from sibling tools or mention any alternative, so it loses one point for lack of sibling differentiation.

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 gives no guidance on when to use this tool versus any sibling tool. There is no mention of prerequisites, alternatives, or situations where this tool is preferred.

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