Check Digit Validator for Cursor

com.gumballtools/check-digit

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

client:Cursor transport:streamable-http tools:1

Install Check Digit Validator in Cursor

~/.cursor/mcp.json · windows: %USERPROFILE%\.cursor\mcp.json

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

Use .cursor/mcp.json in a project root instead to scope it to that project. Cursor merges both. Cursor docs