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

With no annotations, the description carries the full burden, and it does disclose two useful traits: only active companies are returned and results are capped at 20. It says nothing about ordering/relevance, pagination or truncation handling, or whether the match is prefix-only.

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?

Two short sentences: what it searches, then the result cap. Zero filler and the key constraint (20 results) is front-loaded.

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 read-only search with no output schema and fully documented parameters, the definition covers scope, search keys, active-only filtering and result cap. Only the ordering/pagination behavior is missing, which is a modest gap.

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 100%, so the baseline is 3. The description restates the name/CNPJ matching already documented in the consulta parameter and adds nothing about the uf/cidade interaction that the schema flags ("cidade" requires "uf").

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 ("Busca") and resource ("empresas brasileiras ativas") along with the two lookup keys (razão social/fantasia name or CNPJ). The sibling consultar_cnpj is not named, so the boundary between a multi-result search and a single-company lookup has to be inferred from "até 20 resultados".

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 "até 20 resultados" cap implies this is the broad search entry point and that consultar_cnpj is for deeper single-company detail, but the description never says when to prefer one over the other and lists no exclusions. Usage is implied rather than stated.

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