Codex Desktop on Windows ignores mcp_servers.node_repl args/command; node_repl fails with windows sandbox failed: spawn setup refresh

Potential duplicates detected. Please review them and close your issue if it is a duplicate.

• #24718
• #24387
• #24101
• #24416

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I am seeing the same issue on Codex Desktop for Windows.

Codex App version:
26.519.11010.0

Platform:
Windows

Error:
node_repl kernel exited unexpectedly
windows sandbox failed: spawn setup refresh
reason: stdout_eof

Impact:
Chrome plugin/browser automation cannot connect because node_repl fails before it can list tabs.

Additional checks:

• Codex Chrome Extension is installed and enabled in Chrome Default profile.
• Native messaging host manifest exists:

C:\Users\ryoui\AppData\Local\OpenAI\extension\com.openai.codexextension.json

• HKCU registry key exists:

HKCU\Software\Google\Chrome\NativeMessagingHosts\com.openai.codexextension

• Opening Chrome Default profile via the plugin script succeeds.

Update: Running Codex Desktop as Administrator makes Chrome plugin/node_repl work on my machine. Without Administrator, node_repl fails with:
windows sandbox failed: spawn setup refresh

Adding another reproduction from Codex Desktop on Windows that matches this issue.

Environment:

• Codex App package: OpenAI.Codex_26.519.11010.0_x64__2p2nqsd0c76g0
• Bundled Codex CLI used by the runtime: codex-cli 0.133.0
• Chrome / Browser plugin cache version observed: 26.519.81530
• Windows native agent / PowerShell environment

What I verified locally:

• ~/.codex/config.toml contains:

``toml
[mcp_servers.node_repl]
args = ["--disable-sandbox"]
command = '...\\node_repl.exe'
``

• node_repl.exe --help confirms --disable-sandbox is a supported option.
• After fully restarting Codex Desktop multiple times, live node_repl.exe processes are still launched without --disable-sandbox.
• Minimal node_repl JS fails before any browser work:

``text
node_repl kernel exited unexpectedly
node_repl diagnostics: {"kernel_stderr_tail":"windows sandbox failed: spawn setup refresh","reason":"stdout_eof"}
``

• Direct bundled CLI sandbox smoke test also fails in the default/elevated path:

``powershell
codex.exe sandbox windows powershell.exe -NoProfile -Command "Write-Output sandbox-ok"
`
Result:
`text
windows sandbox failed: spawn setup refresh
``

• The sandbox log shows the concrete underlying error:

``text
setup refresh: failed to spawn ...\\codex-windows-sandbox-setup.exe: The requested operation requires elevation. (os error 740)
``

Important distinction:

• Chrome itself appears healthy.
• Codex Chrome Extension is installed and enabled in the active Chrome profile.
• Native messaging host manifest and HKCU registry entry are correct.
• The Chrome native host is able to start extension-host.exe.
• The failure happens below Chrome/browser-client: node_repl cannot start its kernel because the Windows sandbox setup-refresh path fails.

Workaround verification:
Running the same bundled CLI with windows.sandbox="unelevated" succeeds:

codex.exe -c 'windows.sandbox="unelevated"' sandbox windows powershell.exe -NoProfile -Command "Write-Output sandbox-unelevated-ok"

Output:

sandbox-unelevated-ok

So this looks like two linked problems:

1. Codex Desktop ignores or bypasses the user-defined mcp_servers.node_repl.command / args for this plugin-provided Node REPL path.
2. The hardcoded/default Node REPL path then hits the elevated Windows sandbox spawn setup refresh / os error 740 failure, which makes Chrome/browser automation appear unavailable even though the Chrome extension and native host are healthy.

I can reproduce what looks like the same failure on Codex Desktop for Windows.

Environment:

Codex Desktop package: OpenAI.Codex_26.519.11010.0_x64__2p2nqsd0c76g0
Codex CLI path from config: C:\Users\user\AppData\Local\OpenAI\Codex\bin\958d608b5e0546a5\codex.exe
codex.exe --version: codex-cli 0.133.0
Node REPL executable: C:\Users\user\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe
Node path: C:\Users\user\AppData\Local\OpenAI\Codex\bin\5b9024f90663758b\node.exe
Workspace: D:\codex
Windows sandbox config: [windows] sandbox = "elevated"
Minimal repro:

Start Codex Desktop on Windows.

Run a minimal Node REPL MCP call:

nodeRepl.write('ok')
The kernel exits before running the JS:

node_repl kernel exited unexpectedly
node_repl diagnostics: {"kernel_status":"running","kernel_stderr_tail":"windows sandbox failed: spawn setup refresh","reason":"stdout_eof","stream_error":null}
Sandbox log root cause:

[2026-05-29 23:52:30.790 codex.exe] START: C:\Users\user\AppData\Local\OpenAI\Codex\bin\5b9024f90663758b\node.exe --experimental-vm-modules C:\Users\DERICK~1.CHA\AppData\Local\Temp\.tmpo5Xsa5\kernel.js --session-id 6a423ef8e6124c3184cb
[2026-05-29 23:52:30.860 codex.exe] setup refresh: spawning C:\Users\user\AppData\Local\OpenAI\Codex\bin\958d608b5e0546a5\codex-windows-sandbox-setup.exe (cwd=D:\codex, payload_len=4428)
[2026-05-29 23:52:30.865 codex.exe] setup refresh: failed to spawn C:\Users\user\AppData\Local\OpenAI\Codex\bin\958d608b5e0546a5\codex-windows-sandbox-setup.exe: 要求的作業需要提升的權限。 (os error 740)
What I tried:

js_reset, then reran nodeRepl.write('ok'): same failure.

Fully restarted Codex Desktop: same failure.

Set:

[mcp_servers.node_repl]
args = ["--disable-sandbox"]
After restart, the actual process command line was still:

"C:\Users\user\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe"
The --disable-sandbox argument was not present.

Restarted Codex Desktop in administrator mode: nodeRepl.write('ok') succeeds, and runtime metadata is available:

{
"model": "gpt-5.5",
"sandbox": "windows_elevated"
}
This suggests two related issues:

The Node REPL kernel launch path still tries to run codex-windows-sandbox-setup.exe from the user-local 958d608b5e0546a5 CLI bundle, which fails with Windows os error 740.
Codex Desktop appears to ignore mcp_servers.node_repl.args, so users cannot work around this by passing the built-in --disable-sandbox option.
Running Codex Desktop as administrator is a workaround, but the non-admin failure mode is not obvious from the surfaced Node REPL error.
Normal shell tool calls still succeed through the WindowsApps helper path:

setup refresh: spawning C:\Program Files\WindowsApps\OpenAI.Codex_26.519.11010.0_x64__2p2nqsd0c76g0\app\resources\codex-windows-sandbox-setup.exe
setup refresh: processed 2 write roots (read roots delegated); errors=[]
setup binary completed
So the failure seems specific to the Node REPL kernel launch path / MCP launcher config handling rather than all sandboxed shell commands.

Adding another data point from Windows Codex Desktop, but with a stability/performance workaround rather than only a browser-control workaround.

Environment:

• Windows 11 Pro
• Store package: OpenAI.Codex_26.527.7698.0_x64__2p2nqsd0c76g0
• Main bundled runtime observed: codex-cli 0.128.0
• node_repl.exe path was under %LOCALAPPDATA%\OpenAI\Codex\bin\34ab3e1324cc55b5\node_repl.exe

Observed behavior:

• Codex Desktop became increasingly unstable after the 26.527 update: frozen chats, new chats failing to create, and repeated app restarts not clearing the condition.
• RAM was not the bottleneck: after reboot the machine still had ~49 GB free.
• node_repl.exe was spawned even after setting plugin/browser-related config off.
• After restart, the explicit enabled = false I added under [mcp_servers.node_repl] was gone/ignored; the live process still launched as only node_repl.exe, with no useful user-provided args.
• Each node_repl.exe spawned its own child codex.exe app-server --listen stdio://.

Mitigation that materially improved stability:

1. Disable the bundled browser/computer-use plugin:

[plugins."browser@openai-bundled"]
enabled = false

1. Stop running node_repl.exe processes and their direct child codex.exe app-server --listen stdio:// processes.

1. Reversibly rename the local node_repl.exe launchers so Desktop cannot respawn them:

%LOCALAPPDATA%\OpenAI\Codex\bin\34ab3e1324cc55b5\node_repl.exe
%LOCALAPPDATA%\OpenAI\Codex\bin\node_repl.exe

to e.g.

node_repl.exe.disabled-YYYYMMDD-HHMMSS

Impact:

• Internal browser/computer-use automation is disabled/broken by this workaround.
• External browsers and normal Codex chat/task execution continue to work.
• After doing this, the app became dramatically more stable and agents became much faster at processing tasks.

This supports the theory that Desktop is not honoring the user-visible mcp_servers.node_repl config for this path, and that the hardcoded/internal node_repl launcher can become a major stability/performance problem beyond just breaking browser control.

this is now fixed