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

Annotations already declare readOnlyHint=true, idempotentHint=true, destructiveHint=false, aligning with the query nature described. The description adds genuinely useful behavior context beyond annotations: the cost model ('pague por consulta com crédito pré-pago' - pay per query with prepaid credits), data source nature ('a mesma disponível ao cidadão, não é dado sigiloso'), and LGPD data-controller responsibility. This enriches the agent's understanding of side effects (costs) without contradicting the safe read-only annotations. No contradiction found.

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 structured as 4 sentences, front-loading the core purpose first (good) and placing the LGPD statement last (reasonable). However, there is redundancy: 'fonte oficial' is repeated as 'fontes e órgãos oficiais brasileiros (a mesma disponível ao cidadão), não é dado sigiloso', which could be condensed. The sentence is structured as several loosely connected clauses, and the legal/hosting details could be trimmed for a tighter, more scannable description.

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 description handles the compliance/security angle well (LGPD controller responsibility, non-confidential data) which is contextually relevant given the PII parameters (CPF, CNPJ, PKCS12 certs). However, given there is no output schema and no description of return values, format, or failure modes (e.g., what happens when debts are found vs. not), the agent lacks completeness. The tool also handles authentication material (pkcs12_cert, login_senha) without any operational caution, which in combination with the zero output schema weakens its completeness.

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?

With 11 parameters and 0% schema description coverage, the description was expected to compensate but provides zero parameter guidance. While names like 'cpf', 'cnpj', 'uf' are self-evident, critical ambiguities remain unexplained: the distinction between 'login_cpf'/'login_senha' and 'cpf' as identity parameters, the format of 'pkcs12_cert', the meaning of 'preferencia_emissao', and when to use 'ie' vs 'cpf' vs 'cnpj'. The description's perfunctory mention of 'sources and official organs' does not help an agent correctly populate any of these 11 fields.

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 tool name is highly descriptive ('sefaz_certidao_debitos_consultar') and the description confirms 'Certidão Negativa de Débitos Estaduais, consulta em fonte oficial' (query for negative state debt certificates in official sources). This clearly conveys the verb+resource. However, the core purpose is diluted within commercial (pay per query, credits), hosting, and LGPD legal boilerplate, and it doesn't explicitly distinguish itself from a sibling beyond the generic sibling set.

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?

There is no explicit guidance on when to use this tool versus alternatives. The description mentions it queries official Brazilian sources with citizen-level access, which implies scope, but fails to state prerequisites (e.g., what data must be provided: CPF vs CNPJ vs IE), when NOT to use it, or any alternative tools. The LGPD disclaimer is legal context, not usage guidance.

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