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

Annotations already establish readOnly and non-destructive behavior. The description adds useful context that results include temperature, precipitation, and road conditions, but no caveats about forecast range, data source, or units. It is consistent with annotations.

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?

Two sentences, with the core operation front-loaded and a single clarifying second sentence. No filler or repetition.

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 simple read-only forecast tool with fully documented parameters, the description covers what the agent needs to select and call it. It names return categories despite no output schema, though it leaves minor details like units unspecified. Sufficient for correct invocation.

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?

Input schema has 100% description coverage, so the schema already documents location and dates. The description adds no parameter-level detail beyond high-level output content, so baseline 3 is appropriate.

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?

States a specific action and resource: getting weather forecasts for car travel destinations, and mentions road conditions that signal car-specific output. The verb-resource pair and mode qualifier distinguish it from the sibling weather tools.

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?

Description clearly situates the tool for car travel planning, implying use when the travel mode is by car. It does not explicitly name alternative bus/flight/hotel weather tools, but the car qualifier provides sufficient context. No misleading usage information.

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