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

With no annotations, the description carries the full burden. It only states the primary function but does not disclose that most schema parameters are discarded (as hinted by their descriptions), whether the operation is read-only, or what response format to expect. The description omits critical behavioral context for a tool with such a broad schema.

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 that front-loads the core purpose. It contains no filler or redundancy, achieving maximum efficiency for a simple 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?

Despite the schema documenting each parameter, the description lacks critical context for a tool with 9 parameters and no annotations or output schema. It does not explain which parameters are used, how to structure a call, or what the response contains. The mismatch between the description (weather-only) and the broad schema leaves agents uncertain about how to invoke it correctly.

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 each parameter has a description. The tool description adds nothing beyond that; it mentions only 'city' without clarifying that other parameters are irrelevant or used for validation checks. Per the rubric, the baseline of 3 applies when the schema fully documents parameters, and the description does not enhance it.

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's purpose: 'Current temperature for a city via Open-Meteo.' It specifies a concrete verb ('get') and resource (temperature for a city), and distinguishes itself from siblings like geo-hint or timezone by focusing on weather data.

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 on when to use this tool versus alternatives. It does not mention conditions, exclusions, or alternative tools. Given the large sibling set, an agent gets no direction on selecting this tool over others.

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