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

Despite annotations, the description adds substantial behavioral context the annotations cannot convey: pricing (US$ 0,10 per company), the two payment rails (Bearer credit vs X-PAYMENT/x402), same-day credit reuse not recharging, per-call x402 charging, and no charge on failure or nonexistent CNPJ. It also discloses the response is not cached.

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 pricing and payment model is restated three times ('Pago: US$ 0,10 por empresa...', 'Custa US$ 0,10 por empresa...', 'o x402 avulso cobra cada revelação'), producing heavy redundancy. The core reveal purpose is front-loaded, but half the text is duplicated billing detail.

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?

With no output schema, the description carries the return-value burden; it names the revealed fields (sócios, telefones, e-mail) but not the response structure. For a single-parameter paid tool, the billing, idempotency-by-day and no-cache disclosures make it largely complete.

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?

Only one parameter exists and schema coverage is 100%, with 'cnpj' documented as '14 dígitos'. The description adds no format or validation detail beyond the schema, so the baseline of 3 applies.

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 opening sentence states a specific verb and resource: revealing sócios, telefones and e-mail unmasked for a CNPJ. An agent can tell it apart from a plain lookup like get_cnpj by the 'sem máscara' reveal framing, though the description never names that sibling explicitly.

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?

There is no guidance on when to choose this tool over get_cnpj or the other lookup siblings. The text is dominated by payment mechanics rather than selection criteria, so the agent must infer usage from the name and context.

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