Exit both command-line tools with failure status on operational errors

tests/test_cli_regressions.py

@@ -1,5 +1,8 @@
+import importlib
 from threading import Event
+from unittest.mock import patch
 
+import pytest
 from watchdog.events import FileClosedEvent, FileModifiedEvent, FileMovedEvent
 
 from great_ai.deploy.reload_event_handler import ReloadEventHandler
@@ -25,3 +28,18 @@ def test_reload_debounces_edit_and_replacement_events() -> None:
         handler.close()
     handler.dispatch(FileModifiedEvent("service.py"))
     assert calls == ["restart"]
+
+
+@pytest.mark.parametrize(
+    "module_name, operation",
+    [
+        ("great_ai.__main__", "serve"),
+        ("great_ai.large_file.__main__", "handle_command"),
+    ],
+)
+def test_cli_operational_errors_exit_nonzero(module_name: str, operation: str) -> None:
+    module = importlib.import_module(module_name)
+    with patch.object(module, operation, side_effect=ValueError("failed")):
+        with pytest.raises(SystemExit) as error:
+            module.main()
+    assert error.value.code == 1