diff --git a/web/features/agent-v2/agent-detail/configure/components/preview/__tests__/header.spec.tsx b/web/features/agent-v2/agent-detail/configure/components/preview/__tests__/header.spec.tsx
new file mode 100644
index 00000000000..6831b80f672
--- /dev/null
+++ b/web/features/agent-v2/agent-detail/configure/components/preview/__tests__/header.spec.tsx
@@ -0,0 +1,82 @@
+import { QueryClient, QueryClientProvider } from '@tanstack/react-query'
+import { fireEvent, render, screen, waitFor } from '@testing-library/react'
+import { AgentPreviewHeader } from '../header'
+
+const mocks = vi.hoisted(() => ({
+  refreshDebugConversation: vi.fn(),
+}))
+
+vi.mock('@/service/client', () => ({
+  consoleQuery: {
+    agent: {
+      byAgentId: {
+        get: {
+          queryKey: () => ['agent'],
+        },
+        debugConversation: {
+          refresh: {
+            post: {
+              mutationOptions: (options?: { onSuccess?: (data: { debug_conversation_id: string }) => void }) => ({
+                mutationFn: mocks.refreshDebugConversation,
+                ...options,
+              }),
+            },
+          },
+        },
+      },
+    },
+  },
+}))
+
+function renderHeader({
+  onRestart = vi.fn(),
+}: {
+  onRestart?: () => void
+} = {}) {
+  const queryClient = new QueryClient()
+  queryClient.setQueryData(['agent'], {
+    debug_conversation_id: 'debug-conversation-old',
+    name: 'Research Agent',
+  })
+
+  render(
+    <QueryClientProvider client={queryClient}>
+      <AgentPreviewHeader
+        agentId="agent-1"
+        isChatFeaturesOpen={false}
+        onToggleChatFeatures={vi.fn()}
+        onRestart={onRestart}
+      />
+    </QueryClientProvider>,
+  )
+
+  return {
+    queryClient,
+  }
+}
+
+describe('AgentPreviewHeader', () => {
+  beforeEach(() => {
+    vi.clearAllMocks()
+    mocks.refreshDebugConversation.mockResolvedValue({
+      debug_conversation_id: 'debug-conversation-new',
+    })
+  })
+
+  it('should refresh debug conversation before clearing preview chat', async () => {
+    const onRestart = vi.fn()
+    const { queryClient } = renderHeader({ onRestart })
+
+    fireEvent.click(screen.getByRole('button', { name: 'agentV2.agentDetail.configure.preview.restart' }))
+
+    await waitFor(() => expect(mocks.refreshDebugConversation).toHaveBeenCalledWith({
+      params: {
+        agent_id: 'agent-1',
+      },
+    }, expect.any(Object)))
+    expect(queryClient.getQueryData(['agent'])).toEqual(expect.objectContaining({
+      debug_conversation_id: 'debug-conversation-new',
+    }))
+    expect(onRestart).toHaveBeenCalledTimes(1)
+  })
+})