Validar número CNJ, CPF e CNPJ

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

Annotations already declare readOnlyHint, idempotentHint and non-destructive, so the safety profile is covered. The description adds one genuine behavioral detail beyond that: it does not merely validate, it 'devolve o dígito CNJ correto' (returns the corrected digit). It says nothing about behavior on invalid input or error reporting, keeping it at a middling 3.

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 the action first and the rationale in a parenthetical. No filler, though the parenthetical is slightly conversational given the schema already handles formatting.

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 read-only three-parameter tool with no output schema, the description carries the return-value burden but only covers the CNJ case ('devolve o dígito CNJ correto'), leaving unspecified what is returned for CPF and CNPJ or how invalid inputs are reported. Adequate but incomplete.

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 each of the three parameters (cpf, cnpj, numero_processo) is documented in the schema with accepted formatting. The description maps loosely onto the same concepts but adds no syntax or format detail the schema lacks, so the baseline 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 verb 'Confere' plus the resources 'dígitos verificadores' and 'dígito CNJ' state a specific validation action, and the title names CPF/CNPJ, so the scope is clear. It stops short of distinguishing itself from any sibling, but no other sibling is a document validator, so an agent can place it accurately.

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 clause 'o PJe-Calc recusa número de processo com dígito errado' implies the use case (validate a number before feeding it to PJe-Calc), but there is no explicit when-to-use, when-not-to-use, or named alternative. Usage is inferable rather than stated.

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