Brazil Company Lookup

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

No annotations are provided, so the description carries the full burden of behavioral disclosure. It clearly discloses the data source (Receita Federal via BrasilAPI), the accepted input flexibility (formatted or unformatted numeric CNPJs), and the specific return fields. It does not cover rate limits or error behavior, but for a simple read-only registry lookup this is adequate.

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 short, information-dense sentences with the core action front-loaded. Every sentence adds value: purpose, return data, source, and input format guidance.

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 one-parameter lookup tool with an output schema, the description is complete enough to use correctly. It covers the input format, the expected data source, and the main return contents, leaving no critical ambiguity.

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 coverage is 0%, so the description must compensate. It explains that the single parameter is a CNPJ and specifies that formatted or unformatted numeric input is accepted, which the bare string schema does not convey. This is sufficient guidance for the one required parameter.

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?

States a specific verb ('Look up'), a clear resource ('Brazilian company by CNPJ in the federal registry'), and enumerates the returned data. This distinguishes it from sibling tools like validate_tax_id and brazil_bank_lookup.

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 implies its use case: fetching federal registry data about a Brazilian company from a CNPJ. However, it does not explicitly state when to prefer this over siblings such as validate_tax_id or brazil_bank_lookup, nor does it provide exclusions.

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