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

The description adds important behavioral details beyond annotations: each query consumes prepaid credits, no authentication needed, data is from official public sources and not confidential, and LGPD compliance. These are not present in the readOnly/idempotent annotations and enrich understanding of side effects and constraints.

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 moderately verbose with repetition (e.g., 'consulta em fonte oficial' and 'Consulta informação de fontes e órgãos oficiais brasileiros'). It could be tightened without losing meaning, but it is still readable and not overly 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 description explains the data source and payment model but omits crucial context about the optional parameters (cpf, cnpj, instalacao) and does not mention response format or possible errors. For a simple query tool, this leaves significant gaps in understanding.

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 description only mentions 'CEP' as the query parameter, but the schema lists four params (cep, cpf, cnpj, instalacao) with no explanations. It does not clarify the purpose or usage of cpf, cnpj, or instalacao, leaving them completely ambiguous.

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 it is a query tool for CEP data from official sources, using 'consulta em fonte oficial' and 'consulta informação de fontes e órgãos oficiais'. This distinguishes it from sibling tools like authenticate or connect, though 'Download' in the name adds slight ambiguity.

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 provides usage context: requires prepaid credits ('pague por consulta com crédito pré-pago') and no platform credentials ('sem credenciais da plataforma'). This hints when to use it, but does not explicitly compare to alternative tools or state when to avoid it.

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