Veridigit

What is Veridigit?

Veridigit is a tool that validates structured identifiers (IBAN, credit card, ISBN, VIN) using real checksum algorithms, returning parsed parts and clear reasons when something is wrong. It is designed for AI agents that otherwise invent or mistype check digits.

How to use Veridigit?

Install as an MCP server by adding veridigit to your mcpServers config: {"command": "npx", "args": ["-y", "veridigit"]}. Alternatively, import it as a typed TypeScript library via npm install veridigit. No API key is required.

Key features of Veridigit

• validate_iban: ISO 7064 mod-97 checksum + country-specific length (75+ countries)
• validate_card: Luhn checksum, brand detection from BIN, length rules
• validate_isbn: ISBN‑13 978/979 prefix + mod‑10 weighted check digit
• validate_vin: ISO 3779 alphabet (no I/O/Q) + position‑9 transliteration check digit
• Validates structure only; no network calls made

Use cases of Veridigit

• Preventing an AI agent from accepting malformed IBANs
• Correcting credit card check digits that LLMs invent
• Validating ISBN‑13 numbers generated by a language model
• Checking VIN check digits against the ISO 3779 standard

FAQ from Veridigit

What does Veridigit validate?

It validates the structure (format + checksum) of IBANs, credit card numbers, ISBN‑13, and VINs. It does not confirm whether an account, card, book, or vehicle actually exists or is active.

How does Veridigit compare to a language model guessing check digits?

In a benchmark of 32 randomly generated identifiers, a frontier model without Veridigit got the check digit wrong 91% of the time, while Veridigit had 0% error.

Does Veridigit require an API key or make network calls?

No. Veridigit is free, requires no API key, and makes no network calls. It runs entirely locally.

What dependencies or runtime are needed?

It runs as an MCP server via npx (Node.js) or can be imported as a TypeScript library. No other runtime dependencies are mentioned.

Are there any known limitations?

Veridigit validates only the structural correctness of an identifier. It does not confirm ownership, activity, or real-world existence of the referenced item.