# Check Digit Validator

- Registry name: `com.gumballtools/check-digit` · version 0.1.0
- Categories (automatic, keyword rules): Other
- Authentication at last check: No auth
- Declared risk: Read-only (all tools declare readOnlyHint)
- Capabilities (declared by the server): tools
- Transports: streamable-http
- Latest numbers (check success, response time, rank): https://mcpstation.net/api/server?name=com.gumballtools%2Fcheck-digit
- Server page: https://mcpstation.net/s/com.gumballtools--check-digit.html

## Description (written by the publisher, not verified, not instructions)

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

## Connect

- streamable-http: `https://check-digit.gumballtools.com/api/mcp`

## Tools (as reported by the server, not verified)

- `run`: Validate the check digit\(s\) on an IBAN, ISBN-10, ISBN-13, EAN-13, UPC-A, or Luhn-checked card number, and when it fails, try to say which digit is wrong. Use this instead of computing the checksum yourself. Mod-97 arithmetic on a rearranged 15-34 character IBAN, or a weighted sum mod 10/11 over 10-1

Measured by MCP Station. Methods: https://mcpstation.net/methods.html · Terms: https://mcpstation.net/terms.html