fix(cli): fail closed on empty oneshot responses

tests/hermes_cli/test_tui_resume_flow.py

@@ -638,6 +638,30 @@ def test_oneshot_rejects_invalid_only_toolsets(monkeypatch, capsys):
     assert "did not contain any valid toolsets" in err
 
 
+def test_oneshot_fails_closed_on_empty_final_response(monkeypatch, capsys):
+    _stub_plugin_discovery(monkeypatch)
+    import hermes_cli.oneshot as oneshot_mod
+
+    monkeypatch.setattr(oneshot_mod, "_run_agent", lambda *_args, **_kwargs: "")
+
+    assert oneshot_mod.run_oneshot("hello") == 1
+    captured = capsys.readouterr()
+    assert captured.out == ""
+    assert "no final response" in captured.err
+
+
+def test_oneshot_prints_nonempty_final_response(monkeypatch, capsys):
+    _stub_plugin_discovery(monkeypatch)
+    import hermes_cli.oneshot as oneshot_mod
+
+    monkeypatch.setattr(oneshot_mod, "_run_agent", lambda *_args, **_kwargs: "done")
+
+    assert oneshot_mod.run_oneshot("hello") == 0
+    captured = capsys.readouterr()
+    assert captured.out == "done\n"
+    assert captured.err == ""
+
+
 def test_oneshot_filters_invalid_toolsets_before_redirect(monkeypatch, capsys):
     _stub_plugin_discovery(monkeypatch)
     from hermes_cli.oneshot import _validate_explicit_toolsets