{
  "$schema": "https://json-schema.org/draft/2020-12/schema",
  "title": "Cart",
  "description": "A shopping cart.",
  "type": "object",
  "properties": {
    "id": {
      "type": "string",
      "description": "Cart identifier.",
      "example": "cart-abc123"
    },
    "items": {
      "type": "array",
      "description": "Items in the cart.",
      "items": {
        "$ref": "#/$defs/CartItem"
      }
    },
    "subtotal": {
      "type": "number",
      "description": "Cart subtotal before tax.",
      "example": 109.98
    }
  }
}