consultar_cepLook up a Brazilian CEP postal code to retrieve street, neighborhood, city, state, IBGE code, area code, and available coordinates for address validation.
Endereço de um CEP (logradouro, bairro, cidade, UF, código IBGE, DDD e coordenadas quando houver). Grátis, com cota diária por conexão; com BITBUSCA_API_KEY não há cota.
| Name | Required | Description | Default |
|---|---|---|---|
| cep | Yes | CEP com ou sem hífen. |
Changes observed during successful MCP inspections.
v0.1.0Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnly, idempotent, openWorld and non-destructive, so safety is covered. The description adds genuinely non-obvious operational context: the service is free, subject to a daily quota per connection, and the quota disappears when BITBUSCA_API_KEY is supplied. It does not say what happens for an invalid or unfound CEP, but the added quota/auth detail is valuable.
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?
Two short sentences with no filler; the field list and the quota caveat are both load-bearing. The opening noun-phrase fragment rather than a verb clause slightly weakens front-loading.
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?
With no output schema, the description usefully enumerates the returned fields and discloses the quota/key behavior, which is enough to call the tool correctly. It omits error/not-found behavior, which is the main remaining gap for a lookup tool.
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% and the single parameter already documents its format (com ou sem hífen). The description adds no syntax, normalization, or error-handling meaning beyond the schema, so the baseline 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 enumerates the returned resource fields (logradouro, bairro, cidade, UF, IBGE, DDD, coordinates), which makes the resource identifiable, but it never states a verb or that it looks up/retrieves by CEP. It also does nothing to distinguish it from siblings such as consultar_cnpj or cidades_imovel beyond the implicit input type.
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 when-to-use or when-not-to-use guidance, and no mention of alternatives (e.g., using cidades_imovel for the reverse direction). The only contextual clause is about quota, which is behavioral rather than usage routing.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.