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

With no annotations, the description carries the full burden. It indicates a read-oriented retrieval operation ('Ficha de empresa') but does not disclose return format, error behavior, authorization needs, or whether the CNPJ is validated beyond digit count. For a simple getter, this is minimally adequate but not rich.

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 phrase with no redundant words. It is front-loaded with the core purpose. Very concise, though slightly information-sparse.

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 lookup tool with no output schema, the description is enough to understand basic intent, but it does not explain what fields the returned 'ficha' contains or what happens on invalid input. Given the tool's simplicity, this is acceptable but not comprehensive.

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%, and the parameter is already described as '14 dígitos' in the schema. The description adds no new semantic detail beyond reinforcing the exact-number requirement, so the baseline of 3 applies.

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 clearly identifies the resource (company record, 'Ficha de empresa') and the lookup criterion (CNPJ). It is unambiguous and does not repeat the tool name. However, it lacks an explicit verb and does not directly differentiate itself from sibling tools like search or suggest.

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?

Usage is implied rather than stated: 'por CNPJ (14 dígitos)' suggests this is for exact CNPJ lookup as opposed to search or suggestion tools. There is no explicit when-to-use or when-not-to-use guidance, but the 14-digit requirement gives a practical hint.

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