diff --git a/packages/dify-ui/README.md b/packages/dify-ui/README.md
index e9c762073d..cd9485c400 100644
--- a/packages/dify-ui/README.md
+++ b/packages/dify-ui/README.md
@@ -90,6 +90,22 @@ See `[web/docs/overlay-migration.md](../../web/docs/overlay-migration.md)` for t
 - `pnpm -C packages/dify-ui storybook` — Storybook on the default port. Each primitive has `index.stories.tsx`.
 - `pnpm -C packages/dify-ui type-check` — `tsgo --noEmit` for this package only.
 
+### Disabling Animations In Tests
+
+Base UI can wait for `element.getAnimations()` to finish before it unmounts overlays, panels, and transition-driven components. Browser-based test runners can make that timing unstable, especially when tests assert final DOM state rather than animation behavior.
+
+Set the Base UI test flag in a Vitest setup file to skip those waits:
+
+```ts
+(
+  globalThis as typeof globalThis & {
+    BASE_UI_ANIMATIONS_DISABLED: boolean
+  }
+).BASE_UI_ANIMATIONS_DISABLED = true
+```
+
+`packages/dify-ui/vitest.setup.ts` already applies this for primitive tests.
+
 See `[AGENTS.md](./AGENTS.md)` for:
 
 - Component authoring rules (one-component-per-folder, `cva` + `cn`, relative imports inside the package, subpath imports from consumers).
diff --git a/packages/dify-ui/src/toast/__tests__/index.spec.tsx b/packages/dify-ui/src/toast/__tests__/index.spec.tsx
index edbdacd203..51fccf70d8 100644
--- a/packages/dify-ui/src/toast/__tests__/index.spec.tsx
+++ b/packages/dify-ui/src/toast/__tests__/index.spec.tsx
@@ -3,19 +3,20 @@ import { toast, ToastHost } from '../index'
 
 const asHTMLElement = (element: HTMLElement | SVGElement) => element as HTMLElement
 
-declare global {
-  // eslint-disable-next-line vars-on-top
-  var BASE_UI_ANIMATIONS_DISABLED: boolean | undefined
+const dispatchToastMouseOver = (element: HTMLElement | SVGElement) => {
+  element.dispatchEvent(new MouseEvent('mouseover', {
+    bubbles: true,
+  }))
+}
+
+const dispatchToastMouseOut = (element: HTMLElement | SVGElement) => {
+  element.dispatchEvent(new MouseEvent('mouseout', {
+    bubbles: true,
+    relatedTarget: document.body,
+  }))
 }
 
 describe('@langgenius/dify-ui/toast', () => {
-  beforeAll(() => {
-    // Base UI waits for `requestAnimationFrame` + `getAnimations().finished`
-    // before unmounting a toast. Fake timers can't reliably drive that path,
-    // so short-circuit it to keep auto-dismiss assertions deterministic in CI.
-    globalThis.BASE_UI_ANIMATIONS_DISABLED = true
-  })
-
   beforeEach(() => {
     vi.clearAllMocks()
     vi.useFakeTimers()
@@ -28,10 +29,6 @@ describe('@langgenius/dify-ui/toast', () => {
     vi.useRealTimers()
   })
 
-  afterAll(() => {
-    globalThis.BASE_UI_ANIMATIONS_DISABLED = undefined
-  })
-
   it('should render a success toast when called through the typed shortcut', async () => {
     const screen = await render(<ToastHost />)
 
@@ -62,13 +59,13 @@ describe('@langgenius/dify-ui/toast', () => {
     expect(document.body.querySelectorAll('[role="dialog"]')).toHaveLength(3)
     expect(document.body.querySelectorAll('button[aria-label="Close notification"][aria-hidden="true"]')).toHaveLength(3)
 
-    screen.getByRole('region', { name: 'Notifications' }).element().dispatchEvent(new MouseEvent('mouseover', {
-      bubbles: true,
-    }))
+    const viewport = screen.getByRole('region', { name: 'Notifications' }).element()
+    dispatchToastMouseOver(viewport)
 
     await vi.waitFor(() => {
       expect(document.body.querySelector('button[aria-label="Close notification"][aria-hidden="true"]')).not.toBeInTheDocument()
     })
+    dispatchToastMouseOut(viewport)
   })
 
   it('should render a neutral toast when called directly', async () => {
@@ -115,11 +112,11 @@ describe('@langgenius/dify-ui/toast', () => {
       onClose,
     })
 
-    screen.getByRole('region', { name: 'Notifications' }).element().dispatchEvent(new MouseEvent('mouseover', {
-      bubbles: true,
-    }))
+    const viewport = screen.getByRole('region', { name: 'Notifications' }).element()
+    dispatchToastMouseOver(viewport)
 
     await expect.element(screen.getByRole('button', { name: 'Close notification' })).toBeInTheDocument()
+    dispatchToastMouseOut(viewport)
     asHTMLElement(screen.getByRole('button', { name: 'Close notification' }).element()).click()
 
     await vi.waitFor(() => {
@@ -128,21 +125,6 @@ describe('@langgenius/dify-ui/toast', () => {
     expect(onClose).toHaveBeenCalledTimes(1)
   })
 
-  it('should auto dismiss toasts with the Base UI default timeout', async () => {
-    const screen = await render(<ToastHost />)
-
-    toast('Default timeout')
-    await expect.element(screen.getByText('Default timeout')).toBeInTheDocument()
-
-    await vi.advanceTimersByTimeAsync(4999)
-    expect(document.body).toHaveTextContent('Default timeout')
-
-    await vi.advanceTimersByTimeAsync(1)
-    await vi.waitFor(() => {
-      expect(document.body).not.toHaveTextContent('Default timeout')
-    })
-  })
-
   it('should respect the host timeout configuration', async () => {
     const screen = await render(<ToastHost timeout={3000} />)
 
diff --git a/packages/dify-ui/vite.config.ts b/packages/dify-ui/vite.config.ts
index 5f3533c706..f2a2d24e57 100644
--- a/packages/dify-ui/vite.config.ts
+++ b/packages/dify-ui/vite.config.ts
@@ -11,6 +11,7 @@ export default defineConfig({
   },
   test: {
     globals: true,
+    setupFiles: ['./vitest.setup.ts'],
     browser: {
       enabled: true,
       provider: playwright(),
diff --git a/packages/dify-ui/vitest.setup.ts b/packages/dify-ui/vitest.setup.ts
new file mode 100644
index 0000000000..285d6e7760
--- /dev/null
+++ b/packages/dify-ui/vitest.setup.ts
@@ -0,0 +1,5 @@
+(
+  globalThis as typeof globalThis & {
+    BASE_UI_ANIMATIONS_DISABLED: boolean
+  }
+).BASE_UI_ANIMATIONS_DISABLED = true