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

Beyond the annotations (readOnlyHint, idempotentHint, destructiveHint), the description adds essential context: no credentials are required, the operation is paid with prepaid credits, and the data is public, not private or confidential. It also clarifies LGPD compliance responsibility, all of which are important for an agent's decision.

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 four sentences long, each contributing useful information: purpose, hosting/credentials/payment, data classification, and legal responsibility. It is somewhat detailed but not overly verbose for the content it covers.

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 has no output schema, so the description should cover the operation's purpose, cost, access mode, and data sensitivity, which it does adequately. The main gap is the ambiguous parameter guidance, especially the conflict between the description's implied alternatives and the schema's required fields, which could confuse an agent.

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 description mentions 'por CPF, CNPJ ou RNTRC' and uses 'ou' (or), implying that only one of these identifiers is needed. However, the input schema marks all three as required, creating a mismatch. The 'completo' parameter is not described at all, leaving its purpose and effect unexplained, and schema coverage is 0%.

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 it 'consulta' (consults) the regularity of an ANTT-authorized carrier by CPF, CNPJ, or RNTRC, using a specific verb and resource. This distinguishes it from the unrelated sibling tools like authenticate or marketplace.

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 explains that no credentials are needed and that the consultation is paid with prepaid credits, giving clear context on when it is appropriate to use. It does not explicitly exclude alternatives, but the sibling tools are not similar query tools, so the absence of exclusions is minor.

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