Veridigit
veridigit
Verified validation of structured identifiers for AI agents — checksums, not guesses.
LLMs accept malformed IBANs, mistype card check digits, and invent ISBN and VIN check digits — confidently and silently. veridigit gives an agent the real checksum algorithms instead, returning a structured result with the parsed parts and clear reasons when something is wrong.
Benchmark
On 32 randomly generated, non-memorised identifiers, a frontier model with no tool got the check digit wrong 91% of the time (IBAN 100%, VIN 100%, ISBN-13 88%, card/Luhn 75%) — versus 0% for veridigit. Reproducible harness in the repo.
Tools
validate_iban— ISO 7064 mod-97 checksum + country-specific length (75+ countries)validate_card— Luhn checksum, brand detection from the BIN, length rulesvalidate_isbn— ISBN-13: 978/979 prefix + mod-10 weighted check digitvalidate_vin— ISO 3779 alphabet (no I/O/Q) + position-9 transliteration check digit
Install
{ "mcpServers": { "veridigit": { "command": "npx", "args": ["-y", "veridigit"] } } }
Also importable as a typed TypeScript library: npm install veridigit. Free, no API key. Apache-2.0.
Scope
Validates the structure of an identifier (format + checksum). Does not confirm a real, active, or owned account/card/book/vehicle, and makes no network calls.
Server Config
{
"mcpServers": {
"veridigit": {
"command": "npx",
"args": [
"-y",
"veridigit"
]
}
}
}