Country Calling Code Grounding Data

Overview

A country calling code API for phone inputs, signup forms and SMS routing. Pass a two-letter ISO country code such as FR and get its calling codes (+33), common name and official name; calling codes come back as an array because some countries use more than one. Add dialing=true for the international (exit) prefix on every plan. Paid plans add the region and subregion, and in the dialing block the national trunk prefix, the other countries that share the calling code, valid number lengths and example numbers for fixed-line, mobile and toll-free lines, taken from Google's libphonenumber metadata. To check whether a specific number is valid, use Phone Number Validator.

Live Test Country Calling Code Grounding Data Source →

The tool

Once your client is connected to the VerveContext server, this appears in its tool list as CountryCallingCodeGroundingData. It is read-only and open-world — it fetches and never mutates anything on your side — so most clients call it without asking you to confirm.

{
  "name": "CountryCallingCodeGroundingData",
  "arguments": {
    "country": "FR"
  }
}

You do not name the tool yourself; the model picks it. Asking about FR in the terms this source covers is enough for it to reach for CountryCallingCodeGroundingData on its own — naming it explicitly also works, and is the way to force the call.

Connecting

One server URL covers every source in the catalog, including this one. Authorization is OAuth: the client opens a browser once, and there is no key to paste into a config file.

{
  "mcpServers": {
    "vervecontext": {
      "url": "https://api.vervecontext.com/v1/mcp"
    }
  }
}

https://api.vervecontext.com/v1/mcp

Per-client setup — Claude, Cursor, VS Code, ChatGPT — is on the MCP setup page.

Arguments

These are the properties on the tool's inputSchema, so a well-behaved client validates them before the call is made. Premium arguments are accepted on every plan but only take effect on plans that include them.

What the model gets back

The result carries a structuredContent object matching the tool's declared outputSchema, so a client reads fields without parsing prose. status is "ok" and error is null on success; a null field means the value was not available for that input, not that the call failed.

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{
  "status": "ok",
  "error": null,
  "data": {
    "country": "France",
    "officialName": "French Republic",
    "countryCode": "FR",
    "callingcodes": [
      "+33"
    ],
    "region": "Europe",
    "subregion": "Western Europe",
    "dialing": {
      "internationalPrefix": "00",
      "nationalPrefix": "0",
      "sharedWith": [],
      "possibleLengths": {
        "fixedLine": [
          9
        ],
        "mobile": [
          9
        ],
        "tollFree": [
          9
        ]
      },
      "exampleNumbers": {
        "fixedLine": {
          "international": "+33 1 23 45 67 89",
          "national": "01 23 45 67 89",
          "e164": "+33123456789"
        },
        "mobile": {
          "international": "+33 6 12 34 56 78",
          "national": "06 12 34 56 78",
          "e164": "+33612345678"
        },
        "tollFree": {
          "international": "+33 801 23 45 67",
          "national": "0 801 23 45 67",
          "e164": "+33801234567"
        }
      }
    }
  }
}

Response fields

Paths are relative to data. Premium fields are absent rather than zeroed on plans that do not include them, so check for presence instead of comparing to 0.

Why ground on it

A model can produce something that looks like this answer from its training data, and be confidently out of date or simply wrong. This source returns the current value in a shape you can check, which is the difference between an answer you can cite and one you have to hedge.

Point an evaluation at officialName: it is the field most worth pinning a claim to, and it is either present and current or absent — never plausibly invented.

Failure modes

Errors come back as tool errors carrying a sentence the model can act on, not a bare status code. Error handling covers the full list.

A call costs 1 credit each time the tool actually runs; a model that reasons about the tool without calling it costs nothing.

Use cases

Signup Form Prepopulation

When users pick their nationality on signup forms, frontends populate the international phone prefix automatically to avoid input errors.

Contact Record Normalization

Clean customer address books by appending verified country dialing prefixes to local phone numbers stored with ISO country codes.

SMS Gateway Routing

To dispatch two-factor authentication alerts, messaging systems verify recipient phone prefixes against their registered account country.

Logistics Contact Sheets

Shipping platforms convert destination ISO codes into international dialing prefixes so couriers can contact international package recipients.

Other ways to use Country Calling Code Grounding Data

Set up Country Calling Code Grounding Data on VerveContext, or reach the same source a different way. Your VerveContext account and credits work on all of them — one key, one balance.

Related

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