diff --git a/react/src/components/FolderCreateModalV2.tsx b/react/src/components/FolderCreateModalV2.tsx
index 6cce72b567..020e8e6e0d 100644
--- a/react/src/components/FolderCreateModalV2.tsx
+++ b/react/src/components/FolderCreateModalV2.tsx
@@ -649,17 +649,18 @@ const FolderCreateModalV2: React.FC<FolderCreateModalProps> = ({
             {({ getFieldValue }) => {
               const usageMode = getFieldValue('usage_mode');
               const type = getFieldValue('type');
-              const allowOnlyROForModelProjectFolder = baiClient?.supports(
-                'allow-only-ro-permission-for-model-project-folder',
-              );
+              // Model project folders are forced read-only (FR-1290). The
+              // manager used to enforce this server-side (the dropped
+              // 'allow-only-ro-permission-for-model-project-folder' capability)
+              // and no longer seems to, but we keep enforcing it on the client
+              // to preserve that contract until the project-folder behavior is
+              // reworked. Mirrored in VFolderNodeDescriptionV2.
               const shouldDisableRWPermission =
-                usageMode === 'model' &&
-                type === 'project' &&
-                allowOnlyROForModelProjectFolder;
+                usageMode === 'model' && type === 'project';
 
               return (
                 <Form.Item
-                  label={t('data.Permission')}
+                  label={t('data.folders.MountPermission')}
                   name={'permission'}
                   required
                   dependencies={['usage_mode', 'type']}
diff --git a/react/src/components/VFolderNodeDescriptionV2.tsx b/react/src/components/VFolderNodeDescriptionV2.tsx
index 6456bfdafb..59515ef895 100644
--- a/react/src/components/VFolderNodeDescriptionV2.tsx
+++ b/react/src/components/VFolderNodeDescriptionV2.tsx
@@ -21,6 +21,7 @@ import {
   App,
   Descriptions,
   theme,
+  Tooltip,
   Typography,
   type DescriptionsProps,
 } from 'antd';
@@ -128,6 +129,14 @@ const VFolderNodeDescriptionV2: React.FC<VFolderNodeDescriptionV2Props> = ({
       ? 'rw'
       : 'ro';
 
+  // Model project folders are read-only by design (FR-1290), matching
+  // FolderCreateModalV2. The manager used to enforce `ro` server-side and no
+  // longer seems to, but we keep enforcing it on the client to preserve that
+  // contract until the project-folder behavior is reworked.
+  const shouldDisableRWPermission =
+    vfolderNode.metadata?.usageMode === 'MODEL' &&
+    vfolderNode.accessControl?.ownershipType === 'GROUP';
+
   const items: DescriptionsProps['items'] = filterOutEmpty([
     !vfolderNode?.unmanagedPath && {
       key: 'path',
@@ -198,9 +207,27 @@ const VFolderNodeDescriptionV2: React.FC<VFolderNodeDescriptionV2Props> = ({
           defaultValue={currentSelectPermission}
           options={[
             { value: 'ro', label: t('data.ReadOnly') },
-            { value: 'rw', label: t('data.ReadWrite') },
+            {
+              value: 'rw',
+              label: shouldDisableRWPermission ? (
+                <Tooltip
+                  title={t(
+                    'data.folders.ModelProjectFolderRestrictedToReadOnly',
+                  )}
+                >
+                  {t('data.ReadWrite')}
+                </Tooltip>
+              ) : (
+                t('data.ReadWrite')
+              ),
+              disabled: shouldDisableRWPermission,
+            },
           ]}
           onChange={(value) => {
+            // Defense-in-depth: never persist 'rw' for a restricted folder.
+            if (shouldDisableRWPermission && value === 'rw') {
+              return;
+            }
             updateMutation.mutate(
               { permission: value, id: vfolderId },
               {