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

Annotations already declare readOnlyHint=true, destructiveHint=false and openWorldHint=false, so the safety profile is covered. The description adds non-redundant behavioral context the annotations do not carry: no API key required and no quota consumption, which is exactly the kind of operational detail an agent needs before calling.

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 tight sentence that front-loads the purpose and then appends the returned fields and the no-key/no-quota note. No filler, though the commas make it slightly dense rather than optimally readable.

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?

With no output schema, the description compensates by naming what is returned (loaded batch month, generation date, CNPJ quantity), and it covers the auth/quota caveat. Nothing an agent needs to call this status tool correctly is missing.

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 tool takes zero parameters, so per the baseline rule this scores 4. There is nothing for the description to clarify beyond confirming it is a parameterless call, which the empty schema already conveys.

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+resource (status of the service and the CNPJ base) and even enumerates the returned fields (batch month, generation date, CNPJ count). It is clearly distinguishable from the sibling lookup/validation tools by function, though it never names them explicitly.

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: 'Sem chave e sem consumo de cota' tells the agent it can call this freely without a key or quota, which is a useful selection signal. However, it gives no explicit when-to-use vs the consultar_cnpj/validar_cnpj alternatives or any prerequisite conditions.

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