brasil_cepLook up a Brazilian CEP (postal code) and return the address: street, neighborhood, city, and state, with coordinates when available. Example: CEP 01310-100 → Avenida Paulista, Bela Vista, São Paulo, SP.
| Name | Required | Description | Default |
|---|---|---|---|
| cep | Yes | The 8-digit CEP, e.g. "01310-100" or "01310100". |
Changes observed during successful MCP inspections.
Input schema / examplesAdded value: +[
+ {
+ "cep": "01310-100"
+ },
+ {
+ "cep": "01310100"
+ }
+]Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
Annotations already declare readOnlyHint=true and idempotentHint=true, and the description adds value by specifying the returned data (street, neighborhood, city, state, coordinates) and giving an example.
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 a single sentence with an example, highly concise, and front-loaded with the main purpose.
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 read-only lookup with one parameter and no output schema, the description adequately explains input and output. Minor gap: does not mention error handling for invalid CEPs.
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 coverage is 100% and includes a clear example and format. The description repeats the example but adds no new information beyond the schema.
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 the tool's purpose: lookup a Brazilian CEP and return address details. It includes a specific example and distinguishes it from sibling tools like brasil_banks.
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?
While no explicit when-to-use guidance, the straightforward description and example imply usage for CEP lookup. No obvious alternatives among siblings, so no exclusion is needed.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.
Add one secure layer between your agents and this server.