{"name":"card_brand_detect","title":"Card Brand Detector","category":"developer","description":"Luhn-validate a card number and detect its network brand (Visa/Mastercard/Amex/Discover/Diners/JCB/UnionPay) from IIN prefix + length. Formula only, not a real-card check.","price_usd":0.001,"input_schema":{"type":"object","properties":{"number":{"type":"string","description":"Card number (spaces/dashes ignored)"}},"additionalProperties":false,"required":["number"]}}