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

With no annotations, the description carries the behavioral disclosure burden. It explicitly explains that only the curbspec.com free preview is returned and that full writeups, remedies, and itemized services are gated behind a $12.99 unlock. This is useful beyond what the schema provides, though edge-case behavior and potential failures are not covered.

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 with no filler. The primary action and input options are front-loaded, and the paywall behavior is stated economically without unnecessary detail.

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 gives a solid picture of inputs and outputs, including what the report contains and what is locked behind payment, which is important for a tool with no output schema. The main gap is the ambiguous 'year/make/model/mileage' input path and the lack of guidance on which optional parameters must be supplied for a successful call.

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 parameter coverage is 100%, so the baseline is 3. The description adds 'listing paste' as an input style and mentions 'year/make/model/mileage,' but year/make/model are not actual schema properties, and it does not explain how those values should be passed. It adds minimal semantic value beyond the existing per-parameter descriptions.

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 a specific verb and resource: compile a used-vehicle report. It is not a tautology and lists the accepted input forms. However, it introduces 'year/make/model/mileage' as an input path that doesn't map cleanly to the schema, and without sibling tools there is no explicit differentiation to elevate it to a 5.

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 intended use is implied: call this tool when a used-vehicle report is needed from a VIN or listing. There are no explicit when-to-use or when-not-to-use instructions, no alternatives are mentioned, and the description does not clarify which combinations of vin/listing/mileage are valid or preferred.

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