Reference

Data source: Zippopotam.us

MCP MCP Protocol

Endpoint https://context.gnist.ai/mcp/postal-codes/

nobloat — strip report_feedback tool URL-based auth (for clients without header support)

claude_desktop_config.json

{
  "mcpServers": {
    "gnist-postal-codes": {
      "url": "https://context.gnist.ai/mcp/postal-codes/",
      "headers": {
        "Gnist-API-Key": "YOUR_API_KEY"
      }
    }
  }
}

Shell

curl -X POST "https://context.gnist.ai/mcp/postal-codes/" \
  -H "Content-Type: application/json" \
  -H "Accept: application/json, text/event-stream" \
  -H "Gnist-API-Key: YOUR_API_KEY" \
  -d '{"jsonrpc": "2.0", "method": "tools/call", "id": 1, "params": {"name": "lookup_postal_code", "arguments": {"country_code": "example", "postal_code": "example"}}}'

API REST API

API Root https://context.gnist.ai/rest/postal-codes/

4 endpoints available:

GET /rest/postal-codes/lookup_postal_code
GET /rest/postal-codes/search_by_place
GET /rest/postal-codes/list_supported_countries
GET /rest/postal-codes/report_feedback

Shell

curl "https://context.gnist.ai/rest/postal-codes/lookup_postal_code?country_code=example&postal_code=example" \
  -H "Gnist-API-Key: YOUR_API_KEY"

Python

import httpx

resp = httpx.get(
    "https://context.gnist.ai/rest/postal-codes/lookup_postal_code",
    headers={"Gnist-API-Key": "YOUR_API_KEY"},
    params={
        "country_code": "example",
        "postal_code": "example"
},
)
print(resp.json())

OpenAPI Spec · Full API Docs

CLI Command Line

Command gc postal-codes

CLI documentation will be available when the GnistAI SDK is published.

Install

pip install gnistai

Available Tools (4)

lookup_postal_code

Look up location details for a postal/ZIP code — city, state, country, and coordinates.

Parameter	Type	Required	Description
`country_code`	`string`	required	ISO 3166-1 alpha-2 country code (e.g. 'US', 'NO', 'DE').
`postal_code`	`string`	required	Postal or ZIP code to look up (e.g. '90210', '0150').

search_by_place

Find postal codes for a city within a country and state.

Parameter	Type	Required	Description
`country_code`	`string`	required	ISO 3166-1 alpha-2 country code (e.g. 'US', 'DE').
`state`	`string`	required	State or province name (e.g. 'California', 'Bayern').
`city`	`string`	required	City or place name (e.g. 'Los Angeles', 'München').