diff --git a/tests/conftest.py b/tests/conftest.py
index be070f53..56d1d297 100644
--- a/tests/conftest.py
+++ b/tests/conftest.py
@@ -638,4 +638,12 @@ def live_gui() -> Generator["_LiveGuiHandle", None, None]:
    except PermissionError:
     time.sleep(0.5)
    except:
-    break
\ No newline at end of file
+    break
+@pytest.fixture(autouse=True)
+def _check_live_gui_health(request, live_gui) -> Generator[None, None, None]:
+ """[SDM: tests/conftest.py:_check_live_gui_health] [C: every test using live_gui]"""
+ if "live_gui" in request.fixturenames:
+  handle = live_gui
+  handle.ensure_alive()
+ yield
+
diff --git a/tests/test_live_gui_respawn.py b/tests/test_live_gui_respawn.py
new file mode 100644
index 00000000..1b9f09fa
--- /dev/null
+++ b/tests/test_live_gui_respawn.py
@@ -0,0 +1,38 @@
+"""Tests for the _check_live_gui_health autouse fixture (Phase 2, Task 2.2)."""
+import time
+import pytest
+
+
+def test_handle_has_ensure_alive_method(live_gui) -> None:
+ """The _LiveGuiHandle has an ensure_alive() method that is callable."""
+ handle = live_gui
+ assert hasattr(handle, 'ensure_alive')
+ assert callable(handle.ensure_alive)
+
+
+def test_handle_respawn_count_is_zero_on_fresh_start(live_gui) -> None:
+ """A freshly-spawned handle has respawn_count == 0."""
+ handle = live_gui
+ assert handle.respawn_count == 0
+
+
+def test_ensure_alive_is_fast_on_clean_subprocess(live_gui) -> None:
+ """ensure_alive() on a running subprocess is < 100ms (per Phase 2 budget)."""
+ handle = live_gui
+ t0 = time.perf_counter()
+ handle.ensure_alive()
+ elapsed = time.perf_counter() - t0
+ assert elapsed < 0.1, f"ensure_alive took {elapsed:.3f}s on a clean subprocess"
+
+
+def test_is_alive_returns_true_for_running_subprocess(live_gui) -> None:
+ """is_alive() returns True for a running subprocess."""
+ handle = live_gui
+ assert handle.is_alive()
+
+
+def test_autouse_health_fixture_does_not_break_tests(live_gui) -> None:
+ """The _check_live_gui_health autouse fixture runs before this test and calls ensure_alive(). The test should complete without error."""
+ handle = live_gui
+ assert handle.is_alive()  # If the autouse fixture didn't run, the process might be dead
+ assert handle.respawn_count == 0  # No respawns yet