List vehicles

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

Annotations already declare readOnlyHint and openWorldHint, so the safety profile is covered. The description adds useful context that the result is scoped to VINs authorized for this credential, but it does not disclose anything further such as pagination, ordering, or behavior when no vehicles are available.

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, tightly scoped sentence that communicates the action, the resource, and the authorization constraint. Every word earns its place, with 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?

Given that there are no parameters, an output schema exists, and annotations cover read-only and open-world behavior, the description is complete for an agent to select and invoke the tool correctly. It clearly states what is returned (VINs) and the authorization boundary, which is all the agent needs.

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?

There are zero parameters, and schema description coverage is 100%, so there is no parameter ambiguity to resolve. The baseline for a parameterless tool is 4, and the description appropriately focuses on output instead of inputs.

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 uses a specific verb and resource: it lists the VINs authorized for the credential, which clearly distinguishes this from the many get_* siblings that return details about individual vehicles. It is explicit about the scope of the result set, not just a restatement of the title.

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 implies that this tool is for discovering which vehicles the current credential can access, but it does not explicitly state when to use it versus alternatives such as list_domains or the get_* tools. No exclusionary guidance is provided, though the simple no-parameter design makes the intended role fairly clear.

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