diff --git a/src/Controller/MachineStructureController.php b/src/Controller/MachineStructureController.php
index adc4b4f..10f753d 100644
--- a/src/Controller/MachineStructureController.php
+++ b/src/Controller/MachineStructureController.php
@@ -191,6 +191,7 @@ class MachineStructureController extends AbstractController
             $newCf->setDefaultValue($cf->getDefaultValue());
             $newCf->setOptions($cf->getOptions());
             $newCf->setOrderIndex($cf->getOrderIndex());
+            $newCf->setMachineContextOnly($cf->isMachineContextOnly());
             $newCf->setMachine($target);
             $this->entityManager->persist($newCf);
 
diff --git a/src/Service/SkeletonStructureService.php b/src/Service/SkeletonStructureService.php
index c58d177..2f1cd9a 100644
--- a/src/Service/SkeletonStructureService.php
+++ b/src/Service/SkeletonStructureService.php
@@ -233,6 +233,7 @@ class SkeletonStructureService
                 $existingField->setOptions($normalized['options']);
                 $existingField->setDefaultValue($normalized['defaultValue']);
                 $existingField->setOrderIndex($normalized['orderIndex']);
+                $existingField->setMachineContextOnly($normalized['machineContextOnly']);
                 $processedIds[$existingField->getId()] = true;
             } else {
                 // Create new field
@@ -243,6 +244,7 @@ class SkeletonStructureService
                 $cf->setOptions($normalized['options']);
                 $cf->setDefaultValue($normalized['defaultValue']);
                 $cf->setOrderIndex($normalized['orderIndex']);
+                $cf->setMachineContextOnly($normalized['machineContextOnly']);
 
                 match ($category) {
                     ModelCategory::COMPONENT => $cf->setTypeComposant($modelType),
@@ -265,7 +267,7 @@ class SkeletonStructureService
     /**
      * Normalize frontend custom field data to a common shape.
      *
-     * @return array{name: string, type: string, required: bool, options: ?array, defaultValue: ?string, orderIndex: int}
+     * @return array{name: string, type: string, required: bool, options: ?array, defaultValue: ?string, orderIndex: int, machineContextOnly: bool}
      */
     private function normalizeCustomFieldData(array $fieldData, int $index): array
     {
@@ -274,23 +276,25 @@ class SkeletonStructureService
             $value = $fieldData['value'];
 
             return [
-                'name'         => $fieldData['key'],
-                'type'         => $value['type'] ?? 'text',
-                'required'     => (bool) ($value['required'] ?? false),
-                'options'      => $value['options'] ?? null,
-                'defaultValue' => $value['defaultValue'] ?? null,
-                'orderIndex'   => $index,
+                'name'               => $fieldData['key'],
+                'type'               => $value['type'] ?? 'text',
+                'required'           => (bool) ($value['required'] ?? false),
+                'options'            => $value['options'] ?? null,
+                'defaultValue'       => $value['defaultValue'] ?? null,
+                'orderIndex'         => $index,
+                'machineContextOnly' => (bool) ($value['machineContextOnly'] ?? false),
             ];
         }
 
         // PIECE/PRODUCT format: {name, type, required, options?, orderIndex?, defaultValue?}
         return [
-            'name'         => $fieldData['name'] ?? '',
-            'type'         => $fieldData['type'] ?? 'text',
-            'required'     => (bool) ($fieldData['required'] ?? false),
-            'options'      => $fieldData['options'] ?? null,
-            'defaultValue' => $fieldData['defaultValue'] ?? null,
-            'orderIndex'   => $fieldData['orderIndex'] ?? $index,
+            'name'               => $fieldData['name'] ?? '',
+            'type'               => $fieldData['type'] ?? 'text',
+            'required'           => (bool) ($fieldData['required'] ?? false),
+            'options'            => $fieldData['options'] ?? null,
+            'defaultValue'       => $fieldData['defaultValue'] ?? null,
+            'orderIndex'         => $fieldData['orderIndex'] ?? $index,
+            'machineContextOnly' => (bool) ($fieldData['machineContextOnly'] ?? false),
         ];
     }
 }