fix: disable private desktop for harness sandbox

scripts/execute.py

@@ -253,7 +253,12 @@ class StepExecutor:
         prompt = preamble + step_file.read_text(encoding="utf-8")
         command = ["codex", "exec"]
         if os.name == "nt":
-            command.extend(["-c", 'windows.sandbox="unelevated"'])
+            command.extend([
+                "-c",
+                'windows.sandbox="unelevated"',
+                "-c",
+                "windows.sandbox_private_desktop=false",
+            ])
         command.extend([
             "--json",
             "--sandbox",

tests/test_execute.py

@@ -35,8 +35,13 @@ def test_invoke_codex_uses_utf8_for_unicode_prompt(tmp_path, monkeypatch):
     assert "Euler–Bernoulli 보" in invocation["kwargs"]["input"]
     assert invocation["kwargs"]["encoding"] == "utf-8"
     if execute.os.name == "nt":
-        config_index = invocation["command"].index("-c")
-        assert invocation["command"][config_index + 1] == 'windows.sandbox="unelevated"'
+        configs = [
+            invocation["command"][index + 1]
+            for index, argument in enumerate(invocation["command"][:-1])
+            if argument == "-c"
+        ]
+        assert 'windows.sandbox="unelevated"' in configs
+        assert "windows.sandbox_private_desktop=false" in configs
 
 
 def test_run_git_decodes_output_as_utf8(tmp_path, monkeypatch):