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

Beyond the readOnly/idempotent/non-destructive annotations, it discloses prepaid per-query cost, no platform credentials, that data is from official public sources and not confidential, and that the client is data controller under LGPD. These are material behavioral and compliance 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 three sentences, front-loaded with the tool's purpose and scope, and includes essential payment/legal context without being bloated. A structured parameter overview would improve it, but the current size is appropriate.

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?

There is no output schema, no parameter explanations, and the description leaves the required credential parameters and query behavior opaque. It provides good business and compliance context, but not enough for an agent to confidently know how to supply a3/a3_pin/login_cpf/login_senha or what result to expect.

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% for 7 parameters, and the description does not explain a3, a3_pin, login_cpf, or login_senha. Only indirect hints like 'sem credenciais da plataforma' and self-evident names like placa/chassi/renavam reduce the gap, but required auth fields remain unclear.

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 identifies a specific query operation: 'consulta em fonte oficial' against the ECRVSP Veículos state database of SP. It names the resource and scope ('Base Estadual de SP', 'fontes e órgãos oficiais brasileiros') and is distinguishable from the unrelated siblings.

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 communicates clear context: use for querying official Brazilian source data available to citizens, not confidential data, with prepaid credit and without platform credentials. It implies legitimate-purpose scenarios and LGPD responsibility, but does not explicitly contrast against alternatives or state when not to use.

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