Windows Codex Desktop: Computer Use fails before first action because node_repl crashes

Summary

On Windows Codex Desktop, Computer Use is currently unusable because the workflow fails before the first GUI action. The target Windows application itself launches normally, but node_repl crashes or becomes unavailable before Computer Use can begin.

This appears similar to the failure family reported in issues such as #30486 and #26562, but in this case the observed symptom is an early node_repl failure that prevents any Computer Use smoke test from running.

Environment

• Codex Desktop: 26.602.4764.0_x64
• Subscription: ChatGPT Pro
• Platform: Windows x64
• Windows user profile: local Windows account
• Workspace: Google Drive-mounted path containing Japanese characters
• Example workspace: G:\マイドライブ\07_SpaceORAL_Design_Robo
• Target application: EXOCAD DentalDB
• Target executable: C:\exocad\exocad-DentalCAD3.2-2024-02-14\DentalDB\bin\DentalDB.exe
• Model observed during recent failures: GPT-5.6 Codex

What happens

1. Open the project in Codex Desktop for Windows.
2. Ask Codex to launch or interact with a local Windows application using Computer Use.
3. The application itself can launch successfully.
4. Before Codex performs the first Computer Use action, node_repl crashes, disconnects, or becomes unavailable.
5. Codex cannot see, click, type, or continue the GUI workflow.

Expected behavior

Computer Use should initialize its runtime successfully and perform a basic GUI smoke test, such as opening and interacting with Notepad, Calculator, or the target application.

Actual behavior

Computer Use fails before its first GUI action. Rewriting the prompt, simplifying the workflow, and reducing the SOP do not help because the failure occurs at the runtime/tool initialization layer rather than during task reasoning.

Impact

This blocks all Windows GUI automation, including a research-oriented CAD workflow. No patient-identifying information or patient images are involved.

Suspected component

The failure appears to involve the Windows node_repl / Computer Use runtime or sidecar process rather than the target application itself. The application launches independently, but Computer Use cannot initialize.

Requested investigation

Please investigate whether recent Windows Codex Desktop or GPT-5.6 rollout changes introduced a regression in:

• node_repl.exe startup or lifecycle
• exposure of mcp__node_repl__js
• Computer Use sidecar initialization
• Windows sandbox initialization
• handling of mounted paths or non-ASCII workspace paths

It would also help to document the recommended log locations and a minimal diagnostic command for verifying that Computer Use and node_repl are healthy on Windows.