diff --git a/tests/test_tier2_setup_bootstrap.py b/tests/test_tier2_setup_bootstrap.py
new file mode 100644
index 00000000..e30b78dc
--- /dev/null
+++ b/tests/test_tier2_setup_bootstrap.py
@@ -0,0 +1,39 @@
+"""Opt-in integration test for the setup_tier2_clone.ps1 bootstrap.
+
+Runs the script in -WhatIf mode against a fixture workspace. The full
+non-WhatIf run is a manual verification (the user runs it once and
+inspects the result).
+"""
+import os
+import subprocess
+from pathlib import Path
+
+import pytest
+
+pytestmark = [
+ pytest.mark.skipif(
+  not os.environ.get("TIER2_SANDBOX_TESTS"),
+  reason="opt-in: bootstrap test off by default; set TIER2_SANDBOX_TESTS=1",
+ ),
+ pytest.mark.tier2_sandbox,
+]
+
+
+def test_bootstrap_whatif_does_not_create_clone(tmp_path: Path) -> None:
+ """pwsh -WhatIf should print the steps but not actually clone."""
+ fake_main = tmp_path / "fake_main"
+ fake_main.mkdir()
+ fake_clone = tmp_path / "fake_clone"
+ script = Path("scripts/tier2/setup_tier2_clone.ps1").resolve()
+ result = subprocess.run(
+  [
+   "pwsh", "-NoProfile", "-File", str(script),
+   "-MainRepoPath", str(fake_main),
+   "-Tier2ClonePath", str(fake_clone),
+   "-WhatIf",
+  ],
+  capture_output=True, text=True, timeout=60,
+ )
+ assert result.returncode == 0, f"pwsh exit {result.returncode}\nstdout={result.stdout}\nstderr={result.stderr}"
+ assert "What if" in result.stdout or "starting bootstrap" in result.stdout or "Bootstrap Tier 2 clone" in result.stdout
+ assert not fake_clone.exists(), "-WhatIf should not have created the clone"