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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It explains the meaning of the returned fields (rate_code vs display_name) and their relationship to other tools, which is helpful. However, it does not explicitly state that the operation is read-only, nor does it mention any permissions, limits, or potential side effects. For a simple listing tool, this is adequate but not comprehensive.

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 two sentences, front-loaded with the core action ('List vehicle types with specs') followed by the crucial detail about the rate_code field. Every sentence adds essential value, and the examples make it concrete without padding. This is a model of concise, well-structured tool documentation.

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 zero-parameter tool with no output schema, the description covers the key aspects: what the tool returns and how the returned values are used downstream. It explains the distinction between rate_code and display_name, which is critical. However, it does not enumerate all fields returned (e.g., what 'specs' includes), though the examples provide enough context for an agent to proceed. The description is largely complete for the tool's simplicity.

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 tool has zero parameters, so the schema coverage is effectively 100%. The description does not need to explain parameters since there are none. It does, however, clarify the meaning of the output fields, which is valuable for the agent. With no parameters, the baseline score of 4 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?

The description clearly states the verb 'List' and the resource 'vehicle types with specs', making the purpose unambiguous. It further distinguishes this tool from siblings by explicitly noting that the rate_code returned is the exact string consumed by availability, quote, and booking-link tools, which positions it as the canonical source for those values.

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 clear context: use this tool to obtain the exact rate_code string needed by other tools. It does not explicitly mention when not to use it or name alternatives, but the guidance is specific enough to guide an agent. The emphasis on rate_code being the exact input for other tools implies when this tool is relevant.

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