Windows Remote-SSH Codex app-server hangs on shell_command after codex-command-runner launch

What version of the IDE extension are you using?

openai.chatgpt-26.422.30944-win32-x64

What subscription do you have?

ChatGPT Business

Which IDE are you using?

VS Code

What platform is your computer?

Windows

What issue are you seeing?

Environment:

• Windows VM (Running Windows Server 2022) accessed via VS Code Remote-SSH from another Windows machine
• Windows VM OS:

Windows Server 2022 Standard, version 21H2
Build 20348.5020
Architecture: x64

• VS Code extension: openai.chatgpt-26.422.30944-win32-x64
• Codex CLI: 0.125.0
• Workspace: Windows path under D:\Project\...
• Shell: PowerShell
• WSL installed: Ubuntu-24.04, but issue occurs when native Windows app-server is used

Issue:
A trivial shell command such as whoami hangs indefinitely in the VS Code Codex extension over Remote-SSH.

Expected:
shell_command returns stdout/stderr and exits quickly.

Actual:
The command reaches the Windows sandbox, launches codex-command-runner, read ACL setup completes, but no success/failure
is returned to the app-server. The UI/tool call hangs until the user aborts.

Evidence:

• Direct codex.exe sandbox windows ... powershell ... whoami succeeds.
• Native VS Code app-server path hangs:

codex.exe app-server

• Sandbox log shows:
• START powershell whoami
• setup refresh completed
• runner launch completed
• read ACL completed
• no SUCCESS/FAILURE
• No leftover whoami or codex-command-runner process remains after abort.
• Switching the extension app-server to WSL/Linux Codex fixes the hang.

Workaround:
Force VS Code Codex app-server to run via WSL with bundled Linux Codex binary and CODEX_HOME=/root/.codex.

What steps can reproduce the bug?

1. On a Windows VM, install the Codex VS Code extension and connect to the VM from another Windows machine using VS Code

Remote-SSH.

1. Open a Windows workspace in the remote VM, e.g. a path under D:\Perforce\...
2. In the Codex extension chat, ask it to run a trivial shell command:

run whoami

1. Observe that the tool call hangs indefinitely.

1. Check the Windows sandbox log. It shows the command reached the sandbox:

• START powershell whoami
• sandbox setup refresh completed
• codex-command-runner launched
• read ACL setup completed
• no SUCCESS or FAILURE entry is logged afterward

1. Abort the turn. There are no leftover whoami or codex-command-runner processes.

1. Run the same command through direct Windows Codex sandbox / local shell. It succeeds, which suggests the hang is

specific to:
VS Code Remote-SSH extension -> native Windows codex.exe app-server -> Windows sandbox runner result path

1. Workaround: force the extension app-server to run through WSL using the bundled Linux Codex binary. After switching to

WSL, the same whoami command returns successfully.

What is the expected behavior?

Expected:
shell_command returns stdout/stderr and exits quickly.

Additional information

_No response_