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

Annotations already declare read-only, idempotent, and non-destructive behavior. The description adds valuable context: pay-per-query cost, public data source, and LGPD compliance responsibilities. This goes beyond the annotations, informing the agent of non-obvious operational and legal traits.

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 concise three-sentence paragraph, front-loaded with the core function. The additional details on payment and legal responsibility are relevant but slightly verbose for an AI agent. Still, it earns its place by providing useful operational context.

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 tool is relatively simple, and annotations cover safety, while the description covers purpose, data source, and payment. However, missing parameter semantics (especially the role of 'completo') and any mention of response format (no output schema) leave gaps. It is adequate but not fully complete.

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 description coverage is 0%, so the description must compensate. It mentions CPF or CNPJ, which maps to the Cpf and Cnpj parameters, but fails to clarify that both are required per schema (it says 'documento informado', singular, while the schema lists both as required). It also does not explain the 'completo' boolean parameter, leaving ambiguity.

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's function: 'Lista os veículos vinculados a um CPF ou CNPJ' (lists vehicles linked to a CPF or CNPJ), with the scope 'em âmbito nacional' (nationwide). It uses a specific verb and resource, distinguishing it from the unrelated sibling 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?

The description provides clear context on when to use the tool (when you need to list vehicles by provided document) and practical details (hosted by the platform, no credentials, pay-per-query). However, it does not explicitly state when not to use it or mention alternatives, though siblings are unrelated, so this is minor.

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