{"id":"tax-calculator","engine":"core","category":"math","name":"Tax / VAT calculator","fields":[{"key":"amount","label":"Amount","type":"number","default":100,"required":true},{"key":"rate","label":"Tax rate (%)","type":"number","default":20,"required":true,"min":0},{"key":"mode","label":"Amount includes tax","type":"select","default":"net","options":[{"value":"net","label":"No: add tax"},{"value":"gross","label":"Yes: extract tax"}]}],"sample":{"amount":100,"rate":20,"mode":"net"}}