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

With no annotations provided, the description carries the full burden and mostly meets it: it discloses the billing model per plan tier, that errors are not charged, that certain empty/ineligible responses still count as a billed consultation, and that no PDF is returned. It stops short of covering authentication/balance prerequisites or rate limits.

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 most important facts (what it returns, single-document scope, no PDF) are front-loaded, and the per-plan price list is dense but earns its place because it supports the cost-consent gate. The pricing enumeration is long relative to the rest and could be compressed.

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 the description need not explain the response envelope, yet it still enumerates the possible statuses, which helps the agent branch on results. The cost, billing-exception and no-PDF facts cover the main operational surprises; only preconditions such as a funded account are left implicit.

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%, so the schema already documents uf, cpf, cnpj and the confirmo_custo gate in detail. The description adds only the tool-level reinforcement of "um só" (one document at a time); the paid-confirmation behavior it references is already spelled out in the confirmo_custo parameter description, so 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 description states a specific verb and resource ("Consulta a Certidão Negativa de Débitos estadual (ICMS)") scoped to a single CPF/CNPJ in a given UF, and it enumerates the exact return statuses. The word "estadual (ICMS)" plus "um só" document cleanly separates it from the sibling consultar_cnd_federal and from multi-document tools.

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?

It establishes the conditions for use: one document per call, a UF is required, and the PDF is not delivered via MCP (so the agent knows this is a status-only lookup). It does not explicitly name consultar_cnd_federal as the alternative for federal certificates, leaving that routing to be inferred from the name and the "estadual (ICMS)" qualifier.

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