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

No annotations are provided, so the description carries the full burden. It hints the data is 'público' (public), which weakly signals a read-only, non-sensitive operation, but it says nothing about authentication, rate limits, accuracy/freshness of registry data, or error behavior for invalid CNPJs.

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?

A single front-loaded sentence with zero filler: verb first, then resource, then input constraint. Nothing redundant or padded.

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 one-parameter lookup with an output schema present, the definition covers the essential input format and the nature of the result, so return values need not be explained. The remaining gap is routing guidance against enrich_company_ai/search_companies, which is minor given the distinct CNPJ-based semantics.

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% — the schema only declares 'cnpj' as a bare string. The description compensates by giving the critical format constraint (14 digits), which is exactly the information an agent needs to invoke correctly. It does not cover edge cases like formatted vs unformatted input.

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: 'Retorna o dossiê público de uma empresa brasileira' — an agent knows it fetches a full company dossier rather than a list or a search result. The 'a partir do CNPJ' clause shows it is an identifier-keyed lookup, implicitly distinguishing it from list_companies/search_companies, though no sibling is named 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 required CNPJ key implies the use case (you already have a company identifier and want its full record), but there is no explicit when-to-use/when-not guidance and no mention of alternatives such as enrich_company_ai or search_companies. Usage is only implied.

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