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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint), the description adds valuable context: the data is 'ACESSO PÚBLICO', no credentials are required, there is a per-query cost with prepaid credits, and the client is the data controller under LGPD. This significantly enriches the agent's understanding of the tool's behavior and applicable constraints.

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 composed of four sentences, each adding distinct information: purpose, intended user, platform/payment details, and data/legal context. It is front-loaded with the primary purpose and avoids fluff, though it is slightly dense in its middle section.

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 simple read-only query tool, the description covers the main purpose, usage restriction, data public nature, payment model, and LGPD responsibility. It does not explain the 'completo' parameter or the response format, but since there is no output schema and the tool is straightforward, this is a minor gap.

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 schema provides no descriptions for the two parameters (0% coverage). The description only mentions CPF implicitly ('a partir do CPF'), giving it some meaning, but it completely ignores the 'completo' boolean parameter. Thus, the description only partially compensates for the missing schema documentation.

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: 'Consulta a situação da Carteira Nacional de Habilitação (CNH) de uma pessoa a partir do CPF.' It specifies the verb (consulta), the resource (situação da CNH), and the input (CPF), making it distinct 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 usage context: it is intended for the CNH holder to query their own license ('Feito para o titular consultar a própria habilitação'), and notes practical aspects like no credentials and prepaid payment. It does not explicitly mention alternatives, but the sibling tools are not similar, so this is not a significant omission.

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