buscar_empresa

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

With no annotations, the description carries the full burden and does so well: it identifies the data source and its authority, states that the output CNPJ is normalized, lists the returned fields, and enumerates specific failure modes (empty, alphabetic, wrong length, invalid check digits, upstream failure, unregistered CNPJ). It stops short of noting rate limits, authentication needs, or latency characteristics.

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 one dense paragraph of four sentences, front-loaded with purpose, then parameter, return shape, and error modes. Every sentence carries information, though the error enumeration makes it slightly long for a single-parameter lookup.

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 read-only lookup, this covers purpose, input format, output fields, and error conditions, which is close to complete. Since an output schema already exists, the return-field enumeration is partly redundant, and it omits operational details such as whether authentication is needed. Nothing critical for a correct call is missing.

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 the description must compensate, and it does: it declares the parameter required, its type (string), that punctuation is optional, and gives concrete examples in both formats ('12.345.678/0001-90' and '12345678000190'). It also documents the normalization behavior applied on the way out, which the schema does not.

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 gives a specific verb and resource ('Busca dados cadastrais reais de uma empresa a partir do CNPJ') and even names the upstream source (BrasilAPI/Receita Federal), so an agent knows exactly what it retrieves. It does not, however, distinguish itself from plausible siblings such as 'investigar_empresa' or 'buscar_informacoes_publicas', which sound closely related.

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 the overlapping siblings ('investigar_empresa', 'buscar_informacoes_publicas'), nor any stated prerequisites or exclusions. The description only explains the mechanics of a single call, leaving routing entirely to inference.

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