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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false. The description adds valuable behavior context: payment is required per query, data comes from official public sources (not confidential), and the client is responsible for LGPD compliance. This goes beyond the annotations. It does not mention return format or rate limits, but that is not critical given the read-only nature.

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, concise paragraph of four sentences covering the tool's purpose, source, payment, and legal aspects. It contains no fluff and front-loads the core function. It could be more structured (e.g., separated into bullet points), but it remains efficient.

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 description explains the data source, payment model, and legal obligations, but it omits critical invocation details: parameter meanings, expected output, and how to handle optional credentials. With no output schema and 0% parameter coverage, the agent lacks sufficient information to confidently select and correctly invoke the tool.

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 input schema has 6 parameters with 0% description coverage, and the tool description does not explain any of them. While 'placa' and 'renavam' are somewhat self-explanatory, optional parameters like login_cpf, login_senha, pkcs12_cert, and pkcs12_pass are cryptic and unexplained. The description does not compensate for the lack of 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 'DETRAN MS: Veículo, consulta em fonte oficial' and 'Consulta informação de fontes e órgãos oficiais brasileiros', making it obvious this is a vehicle consultation tool for DETRAN MS. It is distinct from sibling tools like authenticate and marketplace, which serve generic platform functions.

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 useful usage context: hosted by the platform, requires prepaid credit ('pague por consulta com crédito pré-pago'), does not require platform credentials, and queries official Brazilian sources. It also mentions LGPD compliance, implying legitimate data use. However, it does not explicitly state when to use this tool over alternatives or mention exclusions.

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