diff --git a/app/generator/components/PreviewPanel.mock-integrations.test.tsx b/app/generator/components/PreviewPanel.mock-integrations.test.tsx
new file mode 100644
index 000000000..12f1a3c9d
--- /dev/null
+++ b/app/generator/components/PreviewPanel.mock-integrations.test.tsx
@@ -0,0 +1,104 @@
+import { describe, it, expect, vi, beforeEach, afterEach } from 'vitest';
+import { render, screen, fireEvent, waitFor } from '@testing-library/react';
+import { PreviewPanel } from './PreviewPanel';
+
+vi.mock('@/utils/clipboard', () => ({
+  fallbackCopyToClipboard: vi.fn(() => true),
+}));
+
+describe('PreviewPanel Mock Integrations', () => {
+  const markdown = '# CommitPulse\nMock integration test';
+
+  beforeEach(() => {
+    Object.assign(navigator, {
+      clipboard: {
+        writeText: vi.fn().mockResolvedValue(undefined),
+      },
+    });
+
+    Object.defineProperty(window, 'isSecureContext', {
+      value: true,
+      configurable: true,
+    });
+
+    vi.spyOn(URL, 'createObjectURL').mockReturnValue('blob:mock');
+    vi.spyOn(URL, 'revokeObjectURL').mockImplementation(() => {});
+  });
+
+  afterEach(() => {
+    vi.restoreAllMocks();
+  });
+
+  it('1. copies markdown using mocked clipboard service', async () => {
+    render(<PreviewPanel markdown={markdown} />);
+
+    fireEvent.click(
+      screen.getByRole('button', {
+        name: /copy markdown text to clipboard/i,
+      })
+    );
+
+    await waitFor(() => {
+      expect(navigator.clipboard.writeText).toHaveBeenCalledWith(markdown);
+    });
+  });
+
+  it('2. downloads markdown using mocked browser APIs', () => {
+    const clickMock = vi.fn();
+
+    const originalCreateElement = document.createElement.bind(document);
+
+    vi.spyOn(document, 'createElement').mockImplementation((tagName: string) => {
+      if (tagName === 'a') {
+        const anchor = originalCreateElement('a');
+        anchor.click = clickMock;
+        return anchor;
+      }
+
+      return originalCreateElement(tagName);
+    });
+
+    render(<PreviewPanel markdown={markdown} />);
+
+    fireEvent.click(
+      screen.getByRole('button', {
+        name: /download readme\.md/i,
+      })
+    );
+
+    expect(URL.createObjectURL).toHaveBeenCalled();
+    expect(clickMock).toHaveBeenCalled();
+  });
+
+  it('3. renders preview content while integrations are mocked', () => {
+    render(<PreviewPanel markdown="# Hello World" />);
+
+    expect(screen.getByRole('tabpanel')).toBeInTheDocument();
+    expect(screen.getByText('README.md')).toBeInTheDocument();
+  });
+
+  it('4. switches between preview and markdown tabs', () => {
+    render(<PreviewPanel markdown={markdown} />);
+
+    fireEvent.click(screen.getByRole('tab', { name: /markdown/i }));
+
+    expect(screen.getByRole('tabpanel')).toBeInTheDocument();
+    expect(screen.getByText(/CommitPulse/)).toBeInTheDocument();
+    expect(screen.getByText(/Mock integration test/)).toBeInTheDocument();
+  });
+
+  it('5. keeps mocked services isolated across repeated interactions', async () => {
+    render(<PreviewPanel markdown={markdown} />);
+
+    const copyButton = screen.getByRole('button', {
+      name: /copy markdown text to clipboard/i,
+    });
+
+    fireEvent.click(copyButton);
+    fireEvent.click(copyButton);
+
+    await waitFor(() => {
+      expect(navigator.clipboard.writeText).toHaveBeenCalledTimes(2);
+    });
+  });
+});