fix: guard transient controls and verify timeline endpoints

tests/unit/test_drivers.py

@@ -284,6 +284,39 @@ async def test_android_driver_parses_xml_hierarchy_fallback():
     assert any(element.get("text") == "Settings" for element in screen_data.ui_elements)
 
 
+@pytest.mark.asyncio
+async def test_android_live_targets_read_fresh_hierarchy_without_screenshot():
+    client = MagicMock()
+    client.get_hierarchy.side_effect = [
+        '<hierarchy><node resource-id="app:id/plus" bounds="[10,20][30,40]"/></hierarchy>',
+        "<hierarchy/>",
+    ]
+    driver = AndroidAdbDriver("test-device", MagicMock(), ui_adb_client=client)
+    driver.get_screen_data = AsyncMock(side_effect=AssertionError("must not capture screen"))
+
+    present = await driver.get_ui_elements()
+    absent = await driver.get_ui_elements()
+
+    assert any(e.get("resource-id") == "app:id/plus" for e in present)
+    assert not any(e.get("resource-id") == "app:id/plus" for e in absent)
+    assert client.get_hierarchy.call_count == 2
+    client.get_screen_data.assert_not_called()
+    driver.get_screen_data.assert_not_called()
+
+
+@pytest.mark.asyncio
+async def test_android_live_hierarchy_errors_do_not_fall_back_to_stale_screen():
+    client = MagicMock()
+    client.get_hierarchy.side_effect = TimeoutError("hierarchy unavailable")
+    driver = AndroidAdbDriver("test-device", MagicMock(), ui_adb_client=client)
+    driver.get_screen_data = AsyncMock()
+
+    with pytest.raises(TimeoutError, match="hierarchy unavailable"):
+        await driver.get_ui_elements()
+
+    driver.get_screen_data.assert_not_called()
+
+
 @pytest.mark.asyncio
 async def test_find_element_prefers_fresh_bounds_over_stale_center():
     """Layout transitions must not leave dynamic element taps at old coordinates."""