Look up a Portuguese postal code to retrieve its district, municipality, locality, covered streets and central point. Resolve 'XXXX-XXX' or 'XXXX' codes into clear geographic details.
Look up a Portuguese postal code (código postal, 'XXXX-XXX' or 'XXXX').
Returns district, municipality, locality and the streets the code covers, plus a central point.
| Name | Required | Description | Default |
|---|---|---|---|
| code | Yes |
| Name | Required | Description | Default |
|---|---|---|---|
No arguments | |||
Changes observed during successful MCP inspections.
v0.1.1Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?
No annotations exist, so the description carries the full behavioral burden. It discloses the accepted input formats and enumerates returned fields, but the returned fields are already declared by the output schema, and it says nothing about error handling or whether the 4-digit short form returns a single match or many.
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, front-loaded with the action and resource, with the format guidance and return contents following in order of need. Nothing is wasted.
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 one-parameter read lookup with an output schema, this covers what an agent needs: the action, the input format, and a preview of the result shape. The only real gap is behavior for invalid or ambiguous code prefixes.
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 0% and the single 'code' parameter is undocumented in the schema, so the description must compensate. It does so by specifying the exact formats 'XXXX-XXX' and 'XXXX', which is the key semantic detail needed to call the tool correctly.
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?
States a specific verb and resource ('Look up a Portuguese postal code') and even gives the accepted code formats. The resource is unambiguous, but the description never differentiates itself from nearby geo siblings such as municipality or where_is.
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?
Usage is only implied: an agent can infer this is for resolving a postal code into district/municipality/locality/streets. There is no explicit when-to-use or when-not, and no alternative tools are named.
Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.