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

Annotations already declare readOnlyHint, idempotentHint, destructiveHint. The description adds the behavioral note that it queries the titular's data, not third-party tracking, and that it uses an official base. This goes beyond the annotations, but it doesn't discuss potential authorization requirements or response details.

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-loads the main purpose, and includes a practical usage note. It is concise and well-structured, though it could be slightly shorter without losing meaning.

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 3-parameter tool with no output schema, the description covers purpose and typical usage but lacks parameter details and any hint about return format. The annotations handle safety, so the description is acceptable for basic invocation but not fully complete for an agent to infer expected outputs or all parameter semantics.

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 coverage is 0%, and the description provides no information about the parameters. CPF and CNPJ are self-explanatory, but 'completo' is ambiguous and could mean full details vs. minimal list. The description should explain these, especially the 'completo' flag, to guide correct invocation.

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 lists vehicles registered under a CPF or CNPJ in an official database, using the verb 'lista' (lists) and the resource (vehicles under a document). It distinguishes itself from siblings like multas_debitos_veiculo (which queries debts per vehicle) by focusing on the owner's registration lookup.

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?

It explicitly states typical usage: the owner or fleet manager looks up plates before consulting debts/infractions, and clarifies it is for the data subject, not third-party tracking. This gives a clear context but does not explicitly mention alternatives or when not to use it, though the sibling list provides context.

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