verificar_cnpjVerifies a Brazilian CNPJ in real time, returning company status, Simples Nacional enrollment, and address. Accepts 14-digit numbers with or without punctuation.
Verifica um CNPJ brasileiro em tempo real (situação cadastral, Simples Nacional, endereço). Pagamento real de $0.02 em USDC (Base mainnet).
| Name | Required | Description | Default |
|---|---|---|---|
| cnpj | Yes | CNPJ brasileiro, 14 dígitos, com ou sem pontuação |
Changes observed during successful MCP inspections.
v1.0.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
The description explicitly discloses a critical side effect: a real payment of $0.02 in USDC on Base mainnet. It also states 'real time' behavior, which implies a network call. No other hidden side effects are apparent, and the verification nature suggests a read-only operation. Given no annotations exist, this transparency is fully carried by the description.
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 two sentences long, efficiently conveying purpose, output details, and cost. There is no fluff or repetition; every word adds value. The structure is clean and easy to parse.
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?
For a simple single-parameter tool, the description covers all necessary aspects: what it does, what data it returns, and the associated cost. It does not require an output schema or error handling details for basic usage. The context is sufficient for an agent to decide and invoke the tool correctly.
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 schema already provides a complete description of the 'cnpj' parameter (14 digits, with or without punctuation). The tool description adds no further meaning about the parameter itself, such as formatting examples or validation rules. Baseline score is appropriate since schema coverage is 100% and the parameter is straightforward.
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 the tool's purpose: verifying a Brazilian CNPJ in real time, and lists the specific data returned (registration status, Simples Nacional, address). This leaves no ambiguity about what the tool does.
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?
While it doesn't explicitly say 'use this instead of other tools,' the focus on CNPJ and the mention of a real payment ($0.02) provide implicit guidance. The sibling tools (validar_cpf, verificar_cep) make the domain clear, and a CNPJ verification naturally falls to this tool.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.