How to add a Gift Card type product to the cart via graphql

I can’t work out the syntax for adding a Gift Card product to the cart using Graphql. What product options need setting?

mutation AddProductToCart($cartId: String!, $product: CartItemInput!) {
    addProductsToCart(cartId: $cartId, cartItems: [$product]) {
        cart {
            id
            ...CartTriggerFragment
            ...MiniCartFragment
            __typename
        }
        __typename
    }
}

fragment CartTriggerFragment on Cart {
    id
    total_quantity
    __typename
}

fragment MiniCartFragment on Cart {
    id
    total_quantity
    prices {
        subtotal_excluding_tax {
            currency
            value
            __typename
        }
        subtotal_including_tax {
            currency
            value
            __typename
        }
        __typename
    }
    ...ProductListFragment
    __typename
}

fragment ProductListFragment on Cart {
    id
    items {
        uid
        product {
            uid
            name
            sku
            url_key
            thumbnail {
                url
                __typename
            }
            stock_status
            ... on ConfigurableProduct {
                variants {
                    attributes {
                        uid
                        __typename
                    }
                    product {
                        uid
                        thumbnail {
                            url
                            __typename
                        }
                        __typename
                    }
                    __typename
                }
                __typename
            }
            __typename
        }
        prices {
            price {
                currency
                value
                __typename
            }
            total_item_discount {
                value
                __typename
            }
            __typename
        }
        quantity
        ... on ConfigurableCartItem {
            configurable_options {
                configurable_product_option_uid
                option_label
                configurable_product_option_value_uid
                value_label
                __typename
            }
            __typename
        }
        __typename
    }
    __typename
}