Check Digit Validator MCP server

Check Digit Validator is a remote MCP server that gives an AI agent 1 tool, among them run. It answers at https://check-digit.gumballtools.com/api/mcp over streamable HTTP, and it listed its tools to an anonymous client, so no sign-in was needed for that. Our probes reached it 9 of 9 times since 5 September 2026; the last check, on 17 October 2026, succeeded.

Validates IBAN/ISBN/EAN/Luhn checksums and finds the one wrong digit

Description as the publisher wrote it.

The 1 tool Check Digit Validator offers

Add Check Digit Validator to your AI client

Every block below points at https://check-digit.gumballtools.com/api/mcp. Pick your client and copy.

claude mcp add --transport http check-digit-validator https://check-digit.gumballtools.com/api/mcp

{
  "mcpServers": {
    "check-digit-validator": {
      "command": "npx",
      "args": ["-y", "mcp-remote", "https://check-digit.gumballtools.com/api/mcp"]
    }
  }
}

{
  "mcpServers": {
    "check-digit-validator": {
      "url": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

{
  "servers": {
    "check-digit-validator": {
      "type": "http",
      "url": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

{
  "context_servers": {
    "check-digit-validator": {
      "url": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

{
  "mcpServers": {
    "check-digit-validator": {
      "serverUrl": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

{
  "mcpServers": {
    "check-digit-validator": {
      "url": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

name: Check Digit Validator
version: 0.0.1
schema: v1
mcpServers:
  - name: Check Digit Validator
    type: streamable-http
    url: https://check-digit.gumballtools.com/api/mcp

{
  "mcpServers": {
    "check-digit-validator": {
      "httpUrl": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

{
  "mcpServers": {
    "check-digit-validator": {
      "type": "http",
      "url": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

{
  "mcpServers": {
    "check-digit-validator": {
      "url": "https://check-digit.gumballtools.com/api/mcp"
    }
  }
}

goose://extension?url=https%3A%2F%2Fcheck-digit.gumballtools.com%2Fapi%2Fmcp&type=streamable_http&id=check-digit-validator&name=Check%20Digit%20Validator

Is Check Digit Validator up right now?

It answered our last check on 17 October 2026 in 822 ms. Over 9 checks since 5 September 2026 it answered 9. Status here comes from Neuronto's own probes, not from the publisher.

MCP servers similar to Check Digit Validator

Questions about Check Digit Validator

Is there an official Check Digit Validator MCP server?

Yes. It is published by gumballtools.com and served from check-digit.gumballtools.com, the vendor's own domain: https://check-digit.gumballtools.com/api/mcp.

How many tools does Check Digit Validator have?

1, as returned by the server's own tools/list on 5 September 2026: run.

Is Check Digit Validator down?

It answered our last check on 17 October 2026 in 822 ms. Over 9 checks since 5 September 2026 it answered 9.

How do I add Check Digit Validator to Cursor?

Put the server under mcpServers in ~/.cursor/mcp.json with the URL https://check-digit.gumballtools.com/api/mcp. The exact JSON is above, with the same setup for Claude Code, Claude Desktop, VS Code, Windsurf, Zed, Gemini CLI and the rest.

Does Check Digit Validator need an API key?

It listed its tools to an anonymous client, so reading the tool list needs no key. Individual tools can still ask for credentials in their own inputs.

Where this comes from

Publisher: com.gumballtools. Endpoint host: check-digit.gumballtools.com. ARD identifier: urn:air:com.gumballtools:mcp:check-digit. First indexed 5 September 2026. The tools are exactly what the server returned; nothing on this page is inferred from its name. Ranking in Neuronto search is never for sale.