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

Annotations already provide readOnlyHint, idempotentHint, and destructiveHint. The description adds valuable context beyond these: the tool is hosted by the platform, requires no credentials, has a prepaid credit cost model, and accesses only public official data. It also notes that the client is responsible for legitimate use under LGPD, which is extra behavioral/legal guidance.

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 two sentences with the core purpose front-loaded in the first sentence. The second sentence adds necessary operational and legal context. It is concise and every sentence earns its place, though the LGPD wording is slightly lengthy.

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 tool is simple with one required and one optional parameter, and no output schema. The description covers purpose, payment model, and data access rules, but the undefined 'completo' parameter is a notable gap that prevents full agent understanding. Overall, it is adequate but not fully complete.

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 two parameters (Cnpj required, completo optional) with no descriptions. The description only mentions CNPJ implicitly as the input ('a partir do CNPJ') and does not explain the 'completo' boolean parameter at all. Since schema coverage is 0%, the description fails to compensate for the missing parameter semantics.

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: 'Emite a certidão conjunta de débitos federais de uma empresa a partir do CNPJ' (issues the joint federal debt certificate for a company based on CNPJ). It specifies the verb, resource, and primary input, and is distinct from all sibling tools, which are generic platform operations.

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 operational context for when to use it: 'sem credenciais' (no credentials) and 'pague por consulta com crédito pré-pago' (pay per query with prepaid credit). It also clarifies the data is public and LGPD-compliant. However, it does not explicitly name alternatives or exclusion conditions, but sibling tools are unrelated.

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