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

The annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the agent knows this is a safe, read-only operation. The description adds no extra behavioral details (e.g., whether authentication is required, rate limits, or what 'complete' data includes). Given the annotations cover safety, the description meets the baseline but doesn't add beyond that. A score of 3 is appropriate.

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 a single, short sentence that front-loads the core purpose. It is concise and to the point, with no fluff.

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 lookup tool with 2 parameters and no output schema, the description is minimal. It does not explain the meaning of the 'completo' flag, the expected format of the CNPJ (e.g., with or without punctuation), or what kind of data will be returned. Given the complexity of a CNPJ lookup (corporate registration data can include a lot), the description is incomplete for an agent to correctly invoke the tool and interpret results.

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%. The description says 'complete registration data' but does not explain what the parameters 'CNPJ' or 'completo' mean. The boolean 'completo' is particularly ambiguous—does it request full data vs. summary? No guidance is provided. With no parameter descriptions in the schema and no compensation in the description, this is severely lacking.

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 'Dados cadastrais completos de um CNPJ' clearly states the tool provides complete registration data for a CNPJ (Brazilian company ID). This distinguishes it from sibling tools like investigacao_pessoa_fisica (individual) and other specific investigation tools, though it doesn't explicitly contrast them. The verb is implicit ('provides') but the resource and scope are clear.

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?

No guidance on when to use this tool versus alternatives. The description does not mention any context, prerequisites, or exclusions. An agent must infer from the name alone that it's for legal entity data, and there's no indication when to choose this over sibling tools like investigacao_vinculos_societarios or investigacao_beneficiario_final.

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