diff --git a/src/external_editor.py b/src/external_editor.py
index bc22490..89f1360 100644
--- a/src/external_editor.py
+++ b/src/external_editor.py
@@ -1,6 +1,7 @@
 """External Editor Launcher - Opens files in external text editors for diff viewing."""
 from __future__ import annotations
 
+import os
 import subprocess
 import tempfile
 from pathlib import Path
@@ -49,22 +50,7 @@ class ExternalEditorLauncher:
 _cached_vscode_config: Optional[TextEditorConfig] = None
 
 
-def auto_detect_vscode() -> Optional[TextEditorConfig]:
-    global _cached_vscode_config
-    if _cached_vscode_config is not None:
-        return _cached_vscode_config
-    vscode_path = _find_vscode_in_registry() or _find_vscode_common_paths()
-    if vscode_path:
-        _cached_vscode_config = TextEditorConfig(
-            name="vscode",
-            path=vscode_path,
-            diff_args=["--new-window", "--diff"]
-        )
-    return _cached_vscode_config
-
-
-def get_default_launcher() -> ExternalEditorLauncher:
-    import subprocess
+def _find_vscode_in_registry() -> Optional[str]:
     paths = []
     reg_keys = [
         r"HKLM\SOFTWARE\Microsoft\Windows\CurrentVersion\Uninstall\*",
@@ -81,7 +67,7 @@ def get_default_launcher() -> ExternalEditorLauncher:
                 line = line.strip()
                 if line and line != "":
                     exe_path = line.strip() + "\\Code.exe"
-                    if subprocess.run(["test", "-f", exe_path], check=False).returncode == 0:
+                    if os.path.exists(exe_path):
                         paths.append(exe_path)
         except Exception:
             pass
@@ -91,7 +77,6 @@ def get_default_launcher() -> ExternalEditorLauncher:
 
 
 def _find_vscode_common_paths() -> Optional[str]:
-    import os
     candidates = [
         r"C:\apps\Microsoft VS Code\Code.exe",
         r"C:\Program Files\Microsoft VS Code\Code.exe",
@@ -105,14 +90,17 @@ def _find_vscode_common_paths() -> Optional[str]:
 
 
 def auto_detect_vscode() -> Optional[TextEditorConfig]:
+    global _cached_vscode_config
+    if _cached_vscode_config is not None:
+        return _cached_vscode_config
     vscode_path = _find_vscode_in_registry() or _find_vscode_common_paths()
     if vscode_path:
-        return TextEditorConfig(
+        _cached_vscode_config = TextEditorConfig(
             name="vscode",
             path=vscode_path,
             diff_args=["--new-window", "--diff"]
         )
-    return None
+    return _cached_vscode_config
 
 
 def get_default_launcher() -> ExternalEditorLauncher:
@@ -151,5 +139,4 @@ def resolve_project_editor_override(project_path: Optional[str]) -> Optional[str
 def create_temp_modified_file(content: str) -> str:
     with tempfile.NamedTemporaryFile(mode="w", suffix="_modified", delete=False, encoding="utf-8") as f:
         f.write(content)
-        return f.name
-pass
+        return f.name
\ No newline at end of file