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

Annotations already mark the tool as read-only, idempotent, and non-destructive. The description goes further, disclosing the payment model ('pague por consulta com crédito pré-pago'), the public nature of the data ('ACESSO PÚBLICO em bases e fontes oficiais'), and LGPD responsibilities. This is rich behavioral context beyond the annotations.

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 three sentences, moving from purpose to payment to legal context, with no redundancy. Every sentence adds value and avoids repeating schema or annotation information.

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?

The description covers the tool's purpose, use case, payment requirements, data source, and LGPD compliance. However, it does not describe the return format or explain the 'completo' parameter, and there is no output schema to fill that 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 coverage is 0%, so the description must compensate. It clarifies that CNPJ refers to companies and CPF to individuals, but the phrase 'CNPJ ou CPF' contradicts the schema which requires both fields. Additionally, the 'completo' boolean parameter is not mentioned at all, leaving its meaning unexplained.

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 the tool's function: 'Identifica o beneficiário final de uma empresa ou pessoa a partir do CNPJ ou CPF, para diligência de compliance.' This specifies the verb, resource, inputs, and purpose, making it distinct from sibling platform tools (authenticate, connect, etc.) which are unrelated.

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 gives an explicit use case ('para diligência de compliance') and context about payment and credentials, but does not mention when not to use it or name alternative tools. Since there are no directly competing siblings, the guidance is adequate but not exhaustive.

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