buscar_cep_por_endereco

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

No annotations are provided, so the description carries the full burden. It discloses two key behaviors: the result cap ('Retorna até 50 CEPs') and the ordering ('ordenados pela proximidade do nome do logradouro'). It does not mention error behavior, edge cases, or any authentication needs, but for a simple search tool, this is acceptable.

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 exactly two sentences, front-loaded with the core purpose, and every sentence adds value. There is no redundant wording or unnecessary detail.

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?

For a simple 3-parameter search tool with no annotations and no output schema, the description covers the essential aspects: what it does, the inputs, the output cap, ordering, and when to use it. It does not detail the exact output structure, but that is not necessary given the tool's simplicity.

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 baseline is 3. The description paraphrases each parameter (UF, cidade, logradouro) but does not add meaningful new information beyond what the schema already provides. It reinforces the Brazilian context but nothing more.

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 opens with a specific verb and resource: 'Pesquisa CEPs brasileiros a partir de informações de endereço'. It explicitly lists the three required inputs (UF, cidade, logradouro) and the output (até 50 CEPs). Since the sibling tool does the reverse (CEP -> endereço), this description clearly distinguishes itself.

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 final sentence provides explicit guidance: 'Útil quando o CEP não é conhecido mas o endereço sim.' This tells the agent when to use this tool. However, it does not explicitly name the alternative tool (buscar_endereco_por_cep), relying on the sibling name for inference, which is a minor gap.

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