diff --git a/vendor/magento/module-checkout/Model/Config.php b/vendor/magento/module-checkout/Model/Config.php
new file mode 100644
index 0000000000000..65a520cc8c22d
--- /dev/null
+++ b/vendor/magento/module-checkout/Model/Config.php
@@ -0,0 +1,37 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\Checkout\Model;
+
+use Magento\Framework\App\Config\ScopeConfigInterface;
+
+class Config
+{
+    public const CART_PREFERENCE_CUSTOMER = "customer";
+    public const CART_PREFERENCE_GUEST = "guest";
+    private const XML_PATH_CART_MERGE_PREFERENCE = 'checkout/cart/cart_merge_preference';
+
+    /**
+     * Config Constructor
+     *
+     * @param ScopeConfigInterface $scopeConfig
+     */
+    public function __construct(
+        private readonly ScopeConfigInterface $scopeConfig
+    ) {
+    }
+
+    /**
+     * Get Cart Merge Preference config to update cart quantities
+     *
+     * @return string
+     */
+    public function getCartMergePreference(): string
+    {
+        return $this->scopeConfig->getValue(self::XML_PATH_CART_MERGE_PREFERENCE);
+    }
+}
diff --git a/vendor/magento/module-checkout/Model/Config/Source/CartMergePreference.php b/vendor/magento/module-checkout/Model/Config/Source/CartMergePreference.php
new file mode 100644
index 0000000000000..96dbf87879239
--- /dev/null
+++ b/vendor/magento/module-checkout/Model/Config/Source/CartMergePreference.php
@@ -0,0 +1,27 @@
+<?php
+/**
+ * Copyright 2025 Adobe
+ * All Rights Reserved.
+ */
+declare(strict_types=1);
+
+namespace Magento\Checkout\Model\Config\Source;
+
+use Magento\Framework\Data\OptionSourceInterface;
+
+class CartMergePreference implements OptionSourceInterface
+{
+    /**
+     * Retrieve options for cart merge preference
+     *
+     * @return array[]
+     */
+    public function toOptionArray(): array
+    {
+        return [
+            ['value' => 'guest', 'label' => __('Guest Priority – Override with guest cart quantity')],
+            ['value' => 'customer', 'label' => __('Customer Priority – Override with customer cart quantity')],
+            ['value' => 'merge', 'label' => __('Merge Quantities – Merge quantities of customer and guest cart')]
+        ];
+    }
+}
diff --git a/vendor/magento/module-checkout/etc/adminhtml/system.xml b/vendor/magento/module-checkout/etc/adminhtml/system.xml
index 944914b34e1ea..3eaa8fe96be94 100644
--- a/vendor/magento/module-checkout/etc/adminhtml/system.xml
+++ b/vendor/magento/module-checkout/etc/adminhtml/system.xml
@@ -57,6 +57,11 @@
                     <label>Enable Clear Shopping Cart</label>
                     <source_model>Magento\Config\Model\Config\Source\Yesno</source_model>
                 </field>
+                <field id="cart_merge_preference" translate="label" type="select" sortOrder="100" showInDefault="1" showInWebsite="0" showInStore="0">
+                    <label>Cart Merge Preference</label>
+                    <source_model>Magento\Checkout\Model\Config\Source\CartMergePreference</source_model>
+                    <comment>Select how cart item quantities should be merged</comment>
+                </field>
             </group>
             <group id="cart_link" translate="label" sortOrder="3" showInDefault="1" showInWebsite="1">
                 <label>My Cart Link</label>
diff --git a/vendor/magento/module-checkout/etc/config.xml b/vendor/magento/module-checkout/etc/config.xml
index ef4afdf8d4b27..1ae26a26de8d6 100644
--- a/vendor/magento/module-checkout/etc/config.xml
+++ b/vendor/magento/module-checkout/etc/config.xml
@@ -21,6 +21,7 @@
                 <number_items_to_display_pager>20</number_items_to_display_pager>
                 <crosssell_enabled>1</crosssell_enabled>
                 <enable_clear_shopping_cart>0</enable_clear_shopping_cart>
+                <cart_merge_preference>merge</cart_merge_preference>
             </cart>
             <cart_link>
                 <use_qty>1</use_qty>
diff --git a/vendor/magento/module-quote-graph-ql/Model/Cart/MergeCarts/CartQuantityValidator.php b/vendor/magento/module-quote-graph-ql/Model/Cart/MergeCarts/CartQuantityValidator.php
index 4d44108a2b0b3..87413f2745ad5 100644
--- a/vendor/magento/module-quote-graph-ql/Model/Cart/MergeCarts/CartQuantityValidator.php
+++ b/vendor/magento/module-quote-graph-ql/Model/Cart/MergeCarts/CartQuantityValidator.php
@@ -1,46 +1,52 @@
 <?php
 /**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
+ * Copyright 2021 Adobe
+ * All Rights Reserved.
  */
 declare(strict_types=1);
 
 namespace Magento\QuoteGraphQl\Model\Cart\MergeCarts;
 
-
+use Magento\Catalog\Model\Product;
 use Magento\CatalogInventory\Api\StockRegistryInterface;
+use Magento\CatalogInventory\Model\Stock;
 use Magento\Framework\Exception\CouldNotSaveException;
 use Magento\Framework\Exception\NoSuchEntityException;
 use Magento\Quote\Api\CartItemRepositoryInterface;
 use Magento\Quote\Api\Data\CartInterface;
 use Magento\Quote\Api\Data\CartItemInterface;
+use Magento\Quote\Model\Quote\Item;
+use Magento\Checkout\Model\Config;
+use Psr\Log\LoggerInterface;
+use Magento\Catalog\Api\Data\ProductInterface;
 
 class CartQuantityValidator implements CartQuantityValidatorInterface
 {
     /**
-     * @var CartItemRepositoryInterface
-     */
-    private $cartItemRepository;
-
-    /**
-     * @var StockRegistryInterface
+     * Array to hold cumulative quantities for each SKU
+     *
+     * @var array
      */
-    private $stockRegistry;
+    private array $cumulativeQty = [];
 
     /**
+     * CartQuantityValidator Constructor
+     *
      * @param CartItemRepositoryInterface $cartItemRepository
      * @param StockRegistryInterface $stockRegistry
+     * @param Config $config
+     * @param LoggerInterface $logger
      */
     public function __construct(
-        CartItemRepositoryInterface $cartItemRepository,
-        StockRegistryInterface $stockRegistry
+        private readonly CartItemRepositoryInterface $cartItemRepository,
+        private readonly StockRegistryInterface $stockRegistry,
+        private readonly Config $config,
+        private readonly LoggerInterface $logger
     ) {
-        $this->cartItemRepository = $cartItemRepository;
-        $this->stockRegistry = $stockRegistry;
     }
 
     /**
-     * Validate combined cart quantities to make sure they are within available stock
+     * Validate combined cart quantities to ensure they are within available stock
      *
      * @param CartInterface $customerCart
      * @param CartInterface $guestCart
@@ -49,28 +55,187 @@ public function __construct(
     public function validateFinalCartQuantities(CartInterface $customerCart, CartInterface $guestCart): bool
     {
         $modified = false;
-        /** @var CartItemInterface $guestCartItem */
+        $this->cumulativeQty = [];
+
+        /** @var \Magento\Quote\Model\Quote $guestCart */
+        /** @var \Magento\Quote\Model\Quote $customerCart */
+        /** @var \Magento\Quote\Model\Quote\Item $guestCartItem */
         foreach ($guestCart->getAllVisibleItems() as $guestCartItem) {
             foreach ($customerCart->getAllItems() as $customerCartItem) {
-                if ($customerCartItem->compare($guestCartItem)) {
-                    $product = $customerCartItem->getProduct();
-                    $stockCurrentQty = $this->stockRegistry->getStockStatus(
-                        $product->getId(),
-                        $product->getStore()->getWebsiteId()
-                    )->getQty();
-                    if ($stockCurrentQty < $guestCartItem->getQty() + $customerCartItem->getQty()) {
-                        try {
-                            $this->cartItemRepository->deleteById($guestCart->getId(), $guestCartItem->getItemId());
-                            $modified = true;
-                        } catch (NoSuchEntityException $e) {
-                            continue;
-                        } catch (CouldNotSaveException $e) {
-                            continue;
-                        }
-                    }
+                if (!$customerCartItem->compare($guestCartItem)) {
+                    continue;
+                }
+
+                $mergePreference = $this->config->getCartMergePreference();
+
+                if ($mergePreference === Config::CART_PREFERENCE_CUSTOMER) {
+                    $this->safeDeleteCartItem((int)$guestCart->getId(), (int)$guestCartItem->getItemId());
+                    $modified = true;
+                    break;
                 }
+
+                $product = $customerCartItem->getProduct();
+                $sku = $product->getSku();
+                $websiteId = (int) $product->getStore()->getWebsiteId();
+
+                $isQtyValid = $customerCartItem->getChildren()
+                    ? $this->validateCompositeProductQty($guestCartItem, $customerCartItem)
+                    : $this->validateProductQty(
+                        $product,
+                        $sku,
+                        $guestCartItem->getQty(),
+                        $customerCartItem->getQty(),
+                        $websiteId
+                    );
+
+                if ($mergePreference === Config::CART_PREFERENCE_GUEST) {
+                    $this->safeDeleteCartItem((int)$customerCart->getId(), (int)$customerCartItem->getItemId());
+                    $modified = true;
+                }
+
+                if (!$isQtyValid) {
+                    $this->safeDeleteCartItem((int)$guestCart->getId(), (int)$guestCartItem->getItemId());
+                    $modified = true;
+                }
+
+                break;
             }
         }
+
+        $this->cumulativeQty = [];
+
         return $modified;
     }
+
+    /**
+     * Validate product quantity against available stock
+     *
+     * @param ProductInterface $product
+     * @param string $sku
+     * @param float $guestItemQty
+     * @param float $customerItemQty
+     * @param int $websiteId
+     * @return bool
+     */
+    private function validateProductQty(
+        ProductInterface $product,
+        string $sku,
+        float $guestItemQty,
+        float $customerItemQty,
+        int $websiteId
+    ): bool {
+        $salableQty = $this->stockRegistry->getStockStatus($product->getId(), $websiteId)->getQty();
+
+        $this->cumulativeQty[$sku] ??= 0;
+        $this->cumulativeQty[$sku] += $this->getCurrentCartItemQty($guestItemQty, $customerItemQty);
+
+        // If backorders are enabled, allow quantities beyond available stock
+        if ($this->isBackordersEnabled($product)) {
+            return true;
+        }
+
+        return $salableQty >= $this->cumulativeQty[$sku];
+    }
+
+    /**
+     * Validate composite product quantities against available stock
+     *
+     * @param Item $guestItem
+     * @param Item $customerItem
+     * @return bool
+     */
+    private function validateCompositeProductQty(Item $guestItem, Item $customerItem): bool
+    {
+        $guestChildren = $guestItem->getChildren();
+        $customerChildren = $customerItem->getChildren();
+
+        foreach ($customerChildren as $customerChild) {
+            $sku = $customerChild->getProduct()->getSku();
+            $guestChild = $this->retrieveChildItem($guestChildren, $sku);
+
+            $guestQty = $guestChild ? $guestItem->getQty() * $guestChild->getQty() : 0;
+            $customerQty = $customerItem->getQty() * $customerChild->getQty();
+
+            $product = $customerChild->getProduct();
+            $websiteId = (int) $product->getStore()->getWebsiteId();
+
+            // If backorders are enabled for this product, skip quantity validation
+            if ($this->isBackordersEnabled($product)) {
+                continue;
+            }
+
+            if (!$this->validateProductQty($product, $sku, $guestQty, $customerQty, $websiteId)) {
+                return false;
+            }
+        }
+
+        return true;
+    }
+
+    /**
+     * Find a child item by SKU in the list of children
+     *
+     * @param CartItemInterface[] $children
+     * @param string $sku
+     * @return CartItemInterface|null
+     */
+    private function retrieveChildItem(array $children, string $sku): ?CartItemInterface
+    {
+        foreach ($children as $child) {
+            /** @var \Magento\Quote\Model\Quote\Item $child */
+            if ($child->getProduct()->getSku() === $sku) {
+                return $child;
+            }
+        }
+
+        return null;
+    }
+
+    /**
+     * Get the current cart item quantity based on the merge preference
+     *
+     * @param float $guestCartItemQty
+     * @param float $customerCartItemQty
+     * @return float
+     */
+    private function getCurrentCartItemQty(float $guestCartItemQty, float $customerCartItemQty): float
+    {
+        return match ($this->config->getCartMergePreference()) {
+            Config::CART_PREFERENCE_CUSTOMER => $customerCartItemQty,
+            Config::CART_PREFERENCE_GUEST => $guestCartItemQty,
+            default => $guestCartItemQty + $customerCartItemQty
+        };
+    }
+
+    /**
+     * Safely delete a cart item by ID, logging any exceptions
+     *
+     * @param int $cartId
+     * @param int $itemId
+     * @return void
+     */
+    private function safeDeleteCartItem(int $cartId, int $itemId): void
+    {
+        try {
+            $this->cartItemRepository->deleteById($cartId, $itemId);
+        } catch (NoSuchEntityException | CouldNotSaveException $e) {
+            $this->logger->error($e->getMessage());
+        }
+    }
+
+    /**
+     * Check if backorders are enabled for the stock item
+     *
+     * @param Product $product
+     * @return bool
+     */
+    private function isBackordersEnabled(Product $product): bool
+    {
+        $backorders = $this->stockRegistry->getStockItem(
+            $product->getId(),
+            $product->getStore()->getWebsiteId()
+        )->getBackorders();
+        return $backorders == Stock::BACKORDERS_YES_NONOTIFY ||
+            $backorders == Stock::BACKORDERS_YES_NOTIFY;
+    }
 }
diff --git a/vendor/magento/module-quote-graph-ql/Model/Resolver/MergeCarts.php b/vendor/magento/module-quote-graph-ql/Model/Resolver/MergeCarts.php
index 7f7889c8174bc..45074a0eacb20 100644
--- a/vendor/magento/module-quote-graph-ql/Model/Resolver/MergeCarts.php
+++ b/vendor/magento/module-quote-graph-ql/Model/Resolver/MergeCarts.php
@@ -1,16 +1,13 @@
 <?php
 /**
- * Copyright © Magento, Inc. All rights reserved.
- * See COPYING.txt for license details.
+ * Copyright 2019 Adobe
+ * All Rights Reserved.
  */
 declare(strict_types=1);
 
 namespace Magento\QuoteGraphQl\Model\Resolver;
 
-use Magento\CatalogInventory\Api\StockRegistryInterface;
-use Magento\Framework\App\ObjectManager;
 use Magento\Framework\Exception\CouldNotSaveException;
-use Magento\Framework\Exception\NoSuchEntityException;
 use Magento\Framework\GraphQl\Config\Element\Field;
 use Magento\Framework\GraphQl\Exception\GraphQlAuthorizationException;
 use Magento\Framework\GraphQl\Exception\GraphQlInputException;
@@ -18,86 +15,33 @@
 use Magento\Framework\GraphQl\Query\ResolverInterface;
 use Magento\Framework\GraphQl\Schema\Type\ResolveInfo;
 use Magento\GraphQl\Model\Query\ContextInterface;
-use Magento\Quote\Api\CartItemRepositoryInterface;
 use Magento\Quote\Api\CartRepositoryInterface;
-use Magento\Quote\Api\Data\CartInterface;
-use Magento\Quote\Api\Data\CartItemInterface;
 use Magento\Quote\Model\Cart\CustomerCartResolver;
+use Magento\Quote\Model\Quote;
 use Magento\Quote\Model\QuoteIdToMaskedQuoteIdInterface;
 use Magento\QuoteGraphQl\Model\Cart\GetCartForUser;
 use Magento\QuoteGraphQl\Model\Cart\MergeCarts\CartQuantityValidatorInterface;
 
-/**
- * Merge Carts Resolver
- *
- * @SuppressWarnings(PHPMD.LongVariable)
- */
 class MergeCarts implements ResolverInterface
 {
     /**
-     * @var GetCartForUser
-     */
-    private $getCartForUser;
-
-    /**
-     * @var CartRepositoryInterface
-     */
-    private $cartRepository;
-
-    /**
-     * @var CustomerCartResolver
-     */
-    private $customerCartResolver;
-
-    /**
-     * @var QuoteIdToMaskedQuoteIdInterface
-     */
-    private $quoteIdToMaskedQuoteId;
-
-    /**
-     * @var CartItemRepositoryInterface
-     */
-    private $cartItemRepository;
-
-    /**
-     * @var StockRegistryInterface
-     */
-    private $stockRegistry;
-
-    /**
-     * @var CartQuantityValidatorInterface
-     */
-    private $cartQuantityValidator;
-
-    /**
+     * MergeCarts Constructor
+     *
      * @param GetCartForUser $getCartForUser
      * @param CartRepositoryInterface $cartRepository
-     * @param CustomerCartResolver|null $customerCartResolver
-     * @param QuoteIdToMaskedQuoteIdInterface|null $quoteIdToMaskedQuoteId
-     * @param CartItemRepositoryInterface|null $cartItemRepository
-     * @param StockRegistryInterface|null $stockRegistry
+     * @param CustomerCartResolver $customerCartResolver
+     * @param QuoteIdToMaskedQuoteIdInterface $quoteIdToMaskedQuoteId
+     * @param CartQuantityValidatorInterface $cartQuantityValidator
+     * @param array $fields
      */
     public function __construct(
-        GetCartForUser $getCartForUser,
-        CartRepositoryInterface $cartRepository,
-        CustomerCartResolver $customerCartResolver = null,
-        QuoteIdToMaskedQuoteIdInterface $quoteIdToMaskedQuoteId = null,
-        CartItemRepositoryInterface $cartItemRepository = null,
-        StockRegistryInterface $stockRegistry = null,
-        CartQuantityValidatorInterface $cartQuantityValidator = null
+        private readonly GetCartForUser $getCartForUser,
+        private readonly CartRepositoryInterface $cartRepository,
+        private readonly CustomerCartResolver $customerCartResolver,
+        private readonly QuoteIdToMaskedQuoteIdInterface $quoteIdToMaskedQuoteId,
+        private readonly CartQuantityValidatorInterface $cartQuantityValidator,
+        private readonly array $fields
     ) {
-        $this->getCartForUser = $getCartForUser;
-        $this->cartRepository = $cartRepository;
-        $this->customerCartResolver = $customerCartResolver
-            ?: ObjectManager::getInstance()->get(CustomerCartResolver::class);
-        $this->quoteIdToMaskedQuoteId = $quoteIdToMaskedQuoteId
-            ?: ObjectManager::getInstance()->get(QuoteIdToMaskedQuoteIdInterface::class);
-        $this->cartItemRepository = $cartItemRepository
-            ?: ObjectManager::getInstance()->get(CartItemRepositoryInterface::class);
-        $this->stockRegistry = $stockRegistry
-            ?: ObjectManager::getInstance()->get(StockRegistryInterface::class);
-        $this->cartQuantityValidator = $cartQuantityValidator
-            ?: ObjectManager::getInstance()->get(CartQuantityValidatorInterface::class);
     }
 
     /**
@@ -109,69 +53,76 @@ public function resolve(
         ResolveInfo $info,
         array $value = null,
         array $args = null
-    ) {
+    ): array {
         if (empty($args['source_cart_id'])) {
-            throw new GraphQlInputException(__(
-                'Required parameter "source_cart_id" is missing'
-            ));
+            throw new GraphQlInputException(__('Required parameter "source_cart_id" is missing'));
+        }
+
+        if (isset($args['destination_cart_id']) && empty($args['destination_cart_id'])) {
+            throw new GraphQlInputException(__('The parameter "destination_cart_id" cannot be empty'));
         }
 
         /** @var ContextInterface $context */
-        if (false === $context->getExtensionAttributes()->getIsCustomer()) {
-            throw new GraphQlAuthorizationException(__(
-                'The current customer isn\'t authorized.'
-            ));
+        if (!$context->getExtensionAttributes()->getIsCustomer()) {
+            throw new GraphQlAuthorizationException(__('The current customer isn\'t authorized.'));
         }
+
         $currentUserId = $context->getUserId();
+        $storeId = (int)$context->getExtensionAttributes()->getStore()->getId();
+        $guestMaskedCartId = $args['source_cart_id'];
+
+        // Resolve destination cart ID
+        $customerMaskedCartId = $args['destination_cart_id'] ?? null;
 
-        if (!isset($args['destination_cart_id'])) {
+        if (!$customerMaskedCartId) {
             try {
                 $cart = $this->customerCartResolver->resolve($currentUserId);
+                $customerMaskedCartId = $this->quoteIdToMaskedQuoteId->execute((int) $cart->getId());
             } catch (CouldNotSaveException $exception) {
                 throw new GraphQlNoSuchEntityException(
                     __('Could not create empty cart for customer'),
                     $exception
                 );
             }
-            $customerMaskedCartId = $this->quoteIdToMaskedQuoteId->execute(
-                (int) $cart->getId()
-            );
-        } else {
-            if (empty($args['destination_cart_id'])) {
-                throw new GraphQlInputException(__(
-                    'The parameter "destination_cart_id" cannot be empty'
-                ));
-            }
         }
 
-        $guestMaskedCartId = $args['source_cart_id'];
-        $customerMaskedCartId = $customerMaskedCartId ?? $args['destination_cart_id'];
+        // Fetch guest and customer carts
+        $customerCart = $this->getCartForUser->execute($customerMaskedCartId, $currentUserId, $storeId);
+        $guestCart = $this->getCartForUser->execute($guestMaskedCartId, null, $storeId);
 
-        $storeId = (int)$context->getExtensionAttributes()->getStore()->getId();
-        // passing customerId as null enforces source cart should always be a guestcart
-        $guestCart = $this->getCartForUser->execute(
-            $guestMaskedCartId,
-            null,
-            $storeId
-        );
-        $customerCart = $this->getCartForUser->execute(
-            $customerMaskedCartId,
-            $currentUserId,
-            $storeId
-        );
+        // Validate cart quantities before merging and reload cart before cart merge
         if ($this->cartQuantityValidator->validateFinalCartQuantities($customerCart, $guestCart)) {
-            $guestCart = $this->getCartForUser->execute(
-                $guestMaskedCartId,
-                null,
-                $storeId
-            );
+            $guestCart = $this->getCartForUser->execute($guestMaskedCartId, null, $storeId);
+            $customerCart = $this->getCartForUser->execute($customerMaskedCartId, $currentUserId, $storeId);
         }
+
+        // Merge carts and save
         $customerCart->merge($guestCart);
         $guestCart->setIsActive(false);
+        // Check and update gift options from guest cart to customer cart
+        $customerCart = $this->updateGiftOptions($guestCart, $customerCart);
+
         $this->cartRepository->save($customerCart);
         $this->cartRepository->save($guestCart);
-        return [
-            'model' => $customerCart,
-        ];
+
+        return ['model' => $customerCart];
+    }
+
+    /**
+     * Check and update gift options in customer cart from guest cart
+     *
+     * @param Quote $guestCart
+     * @param Quote $customerCart
+     * @return Quote
+     */
+    private function updateGiftOptions(Quote $guestCart, Quote $customerCart): Quote
+    {
+        foreach ($this->fields as $field) {
+            if (!empty($guestCart->getData($field)) && empty($customerCart->getData($field))) {
+                $customerCart->setData($field, $guestCart->getData($field));
+            }
+        }
+
+        return $customerCart;
     }
 }
diff --git a/vendor/magento/module-quote-graph-ql/etc/graphql/di.xml b/vendor/magento/module-quote-graph-ql/etc/graphql/di.xml
index 83942f1daebb2..59e1abf1e93e3 100644
--- a/vendor/magento/module-quote-graph-ql/etc/graphql/di.xml
+++ b/vendor/magento/module-quote-graph-ql/etc/graphql/di.xml
@@ -70,6 +70,14 @@
                 <item name="minicart_display" xsi:type="string">checkout/sidebar/display</item>
                 <item name="minicart_max_items" xsi:type="string">checkout/sidebar/max_items_display_count</item>
                 <item name="cart_expires_in_days" xsi:type="string">checkout/cart/delete_quote_after</item>
+                <item name="cart_merge_preference" xsi:type="string">checkout/cart/cart_merge_preference</item>
+            </argument>
+        </arguments>
+    </type>
+    <type name="Magento\QuoteGraphQl\Model\Resolver\MergeCarts">
+        <arguments>
+            <argument name="fields" xsi:type="array">
+                <item name="gift_message_id" xsi:type="string">gift_message_id</item>
             </argument>
         </arguments>
     </type>
diff --git a/vendor/magento/module-quote-graph-ql/etc/schema.graphqls b/vendor/magento/module-quote-graph-ql/etc/schema.graphqls
index 53da2d8751127..b2323999d0b39 100644
--- a/vendor/magento/module-quote-graph-ql/etc/schema.graphqls
+++ b/vendor/magento/module-quote-graph-ql/etc/schema.graphqls
@@ -515,6 +515,7 @@ type StoreConfig {
     minicart_display: Boolean @doc(description: "Extended Config Data - checkout/sidebar/display")
     minicart_max_items: Int @doc(description: "Extended Config Data - checkout/sidebar/count")
     cart_expires_in_days: Int @doc(description: "Extended Config Data - checkout/cart/delete_quote_after")
+    cart_merge_preference: String! @doc(description: "Configuration data from checkout/cart/cart_merge_preference")
 }
 
 input EstimateTotalsInput {