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

With no annotations, the description carries the disclosure burden: 'Consulta' plus enumerating read-only fields makes the fetch-only nature clear. It still omits what happens when the CNPJ is not found or the company is inactive, which is the key behavioral risk for this tool.

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 purpose is front-loaded in the first sentence and the args block is short. The enumeration of return fields is somewhat redundant given an output schema exists, but it stays compact and readable.

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 single-parameter read-only lookup with an output schema, the definition covers what it fetches and how to format the input. The main gap is error/not-found behavior, but overall an agent has enough to invoke it 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?

Schema coverage is 0% and the single parameter is only typed as a bare string. The description adds real value by stating the CNPJ may be passed with or without punctuation/mask, directly resolving the main input-format ambiguity.

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 and resource: consult the complete registration record of a company by its CNPJ, and enumerates the returned fields (razão social, QSA, etc.). This clearly distinguishes it from siblings like search_company_by_name or get_company_partners, though it does not name those siblings 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?

The phrase 'de uma empresa ativa' implies the CNPJ must correspond to an active company, and the verb 'Consulta' signals a lookup rather than a search. However, there is no explicit when-to-use vs alternatives guidance (e.g., 'use this once you have a CNPJ; use search_company_by_name if you only have a name'), leaving routing to inference.

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