diff --git a/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view.test.ts b/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view.test.ts
index 46eb167bd1b1..97c6e0776b0f 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view.test.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view.test.ts
@@ -162,7 +162,10 @@ describe('AIAssistantView', () => {
 
       expect(mockAIAssistantController.getMessageStore).toHaveBeenCalledTimes(1);
       expect(aiChatConfig.chatOptions).toEqual(expect.objectContaining({
-        dataSource: mockMessageStore,
+        dataSource: expect.objectContaining({
+          store: mockMessageStore,
+          pushAggregationTimeout: 0,
+        }),
         reloadOnChange: true,
         onMessageEntered: expect.any(Function),
       }));
diff --git a/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view_controller.integration.test.ts b/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view_controller.integration.test.ts
index ccd53fa31c3a..d39acd4706ab 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view_controller.integration.test.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/__tests__/ai_assistant_view_controller.integration.test.ts
@@ -463,4 +463,73 @@ describe('AIAssistantViewController', () => {
       expect(getMessageStatusClass($messages.eq(0))).toBe(MessageStatus.Success);
     });
   });
+
+  describe('manual store push', () => {
+    // eslint-disable-next-line @typescript-eslint/init-declarations
+    let validateSpy;
+    // eslint-disable-next-line @typescript-eslint/init-declarations
+    let executeCommandsSpy;
+
+    beforeEach(() => {
+      validateSpy = jest.spyOn(GridCommands.prototype, 'validate')
+        .mockReturnValue(true);
+      executeCommandsSpy = jest.spyOn(GridCommands.prototype, 'executeCommands')
+        .mockResolvedValue([
+          { status: 'success', message: 'Done' },
+        ] as CommandResult[]);
+    });
+
+    afterEach(() => {
+      validateSpy.mockRestore();
+      executeCommandsSpy.mockRestore();
+    });
+
+    it('should not throw error when user message is manually pushed to the message store', async () => {
+      // eslint-disable-next-line @typescript-eslint/init-declarations
+      let chatStore;
+      const { aiIntegration } = createMockAIIntegration();
+
+      await createDataGrid({
+        dataSource: [
+          { id: 1, name: 'Name 1' },
+        ],
+        columns: [
+          { dataField: 'id', caption: 'ID', dataType: 'number' },
+          { dataField: 'name', caption: 'Name', dataType: 'string' },
+        ],
+        aiAssistant: {
+          enabled: true,
+          aiIntegration,
+          chat: {
+            user: { id: 'user' },
+            onInitialized: (e) => {
+              chatStore = e.component?.getDataSource().store();
+            },
+          },
+          popup: {
+            visible: true,
+          },
+        },
+      });
+
+      try {
+        chatStore.push([{
+          type: 'insert',
+          data: {
+            id: 'manual-msg-1',
+            author: { id: 'user', name: 'User' },
+            text: 'Sort by name',
+            timestamp: new Date().toISOString(),
+          },
+        }]);
+
+        await flushAsync();
+        await flushAsync();
+      } catch (error) {
+        expect(error).toBeUndefined(); // Force fail if error is thrown
+      }
+
+      expect(true).toBe(true);
+    });
+  });
 });
diff --git a/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/ai_assistant_view.ts b/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/ai_assistant_view.ts
index cca5ac0776c7..1c7514a8b157 100644
--- a/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/ai_assistant_view.ts
+++ b/packages/devextreme/js/__internal/grids/grid_core/ai_assistant/ai_assistant_view.ts
@@ -129,7 +129,10 @@ export class AIAssistantView extends View {
 
   private getAIChatOptions(): ChatProperties {
     return {
-      dataSource: this.messageStore,
+      dataSource: {
+        store: this.messageStore,
+        pushAggregationTimeout: 0,
+      },
       reloadOnChange: true,
       onMessageEntered: (e): void => {
         this.executeRequest(e.message);