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

Annotations already declare readOnly, idempotent, non-destructive. Description adds operational details: hosted by platform, no credentials, prepaid credit cost, data is public not private, and LGPD data controller responsibility. These go beyond annotation hints and are consistent with them. No contradiction.

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?

Three sentences, each adds unique information: purpose, payment/credentials, and data legal context. The first sentence is the core purpose, followed by necessary operational details. Slightly long due to LGPD clause, but every sentence earns its place.

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?

Despite annotations, the tool has 4 parameters and no output schema. Description provides high-level context (public data, cost, no credentials) but leaves critical parameter semantics unexplained and does not describe what result records contain. An agent would struggle to correctly invoke this tool without additional information.

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 description must compensate. It only explains Cpf/Cnpj as identifiers, but fails to clarify 'Tipo' or 'completo'. Additionally, it says 'a partir do CPF ou CNPJ' while the schema requires both Cpf and Cnpj, creating confusion about how to fill them. This is insufficient for correct invocation.

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?

Description clearly states the tool queries records of a person or company at CGU using CPF or CNPJ. This is a specific verb ('consulta') + resource ('registros na CGU') and stands out from unrelated sibling tools like authenticate or connect.

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?

Provides clear context: use when needing CGU public data, no credentials required, pay per query with prepaid credit. It does not explicitly name alternatives, but sibling tools are unrelated, so no alternative is needed. The context is sufficient for an agent to decide when to use it.

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