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

Annotations already declare readOnlyHint=true, idempotentHint=true, and destructiveHint=false, so the safe read nature is known. The description adds valuable behavioral details beyond annotations: it is a paid operation requiring prepaid credit, does not use platform credentials, and the client is the data controller under LGPD. This informs the agent about cost and legal responsibilities, which is useful context not captured in the schema.

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 run-on paragraph that mixes the tool's purpose with payment details, data sensitivity, and LGPD compliance. It is not front-loaded efficiently; the core purpose is stated but immediately followed by tangential legal and payment information. Several sentences could be condensed or moved to additional metadata. It lacks the crispness of a well-structured tool description.

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 read-only query with a single parameter, the description is incomplete. It does not explain the expected format of the CNPJ, what the response contains (e.g., entity name, status, dates), or any error conditions such as invalid CNPJ or insufficient credit. It touches on payment and LGPD but omits practical usage details. Given there is no output schema, the description should have provided more on return values and edge cases.

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?

The input schema has one required parameter, 'cnpj', defined only as a string. The description does not explain the parameter at all: no mention that it is a Brazilian company registration number, no format guidance (e.g., digits only, with or without punctuation), no example. With schema description coverage at 0%, the description fails to compensate, leaving the agent without essential guidance for correctly providing the CNPJ.

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 states it is a query to the Transparency Portal's CEPIM registry, an official Brazilian source for non-profit entities impeded from receiving public funds. While the verb 'consultar' and the resource are specific, it could be more explicit about exactly what information is returned (e.g., entity status details). It does distinguish itself from the generic sibling tools (authenticate, connect, etc.) as a data lookup.

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 description provides usage context: it is hosted by the platform, requires no platform credentials, and is a paid query using prepaid credit. It also notes the data is not confidential and that LGPD compliance is the customer's responsibility. However, it does not explicitly state when to use this tool versus alternatives (e.g., when needing to check the impediment status of a specific CNPJ), nor does it specify when not to use it. The guidance is implied but not direct.

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