Validar CPF/CNPJ

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

Annotations already declare readOnlyHint, idempotentHint and openWorldHint=false, so the safety profile is covered. The description adds that validation is offline ('sem rede') and that both numeric and alphanumeric forms are accepted, which is useful context beyond the annotations, but it says nothing about handling of punctuation or malformed input.

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?

A single front-loaded sentence with no filler; the core action, the accepted formats and the offline constraint all appear immediately.

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?

An output schema exists, so return values need no explanation, and the tool is simple. However, for a validation tool the description omits the practically important detail of whether formatted/masked documents are accepted, leaving a real gap for correct invocation.

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% and the single 'documento' parameter is undocumented in the schema, so the description must compensate. It does partially, by stating the parameter accepts CPF or CNPJ in numeric or alphanumeric form, but it does not clarify whether masked input (dots, slashes, dashes) is accepted.

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 ('Valida') and a precise resource ('dígitos verificadores de um CPF ou CNPJ'), and the 'sem rede' clause implicitly separates it from network-based siblings like consultar_cnpj. It stops short of naming an alternative explicitly, so it is clear but not fully differentiated.

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 only implied: the agent can infer this is for check-digit validation rather than data lookup, and that it works offline. There is no explicit when-to-use/when-not statement or named alternative, so guidance is adequate but thin.

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