{"tool":"luhn-check","title":"Luhn check","description":"Validate any 12-19 digit number by the Luhn mod-10 algorithm (card-style checksums). Never submit real card numbers.","method":"POST","call":"/v1/tools/luhn-check/call","input_schema":{"type":"object","required":["number"],"properties":{"number":{"type":"string","description":"12-19 digit number; spaces/dashes allowed."}}},"output_schema":{"type":"object","properties":{"tool":{"type":"string"},"valid":{"type":"boolean"},"normalized":{"type":"string"},"country":{"type":"string"},"reason":{"type":"string"},"scope":{"type":"string"}},"required":["valid","reason"]},"price_usdc_floor":0.000999,"price_note":"dynamic-dutch: live quote via GET /health or the 402 challenge on POST without payment","example_request":{"input":{"number":"4111111111111111"}},"docs":"https://rail.akrivis.in/openapi.json","mcp":"https://rail.akrivis.in/mcp"}