codex - 💡(How to fix) Fix Codex Desktop on Windows ignores mcp_servers.node_repl args/command; node_repl fails with windows sandbox failed: spawn setup refresh

What version of the Codex App are you using (From “About Codex” dialog)?

26.519.10634.0

What subscription do you have?

plus

What platform is your computer?

Windows 10 Home, 64-bit, AMD64

What issue are you seeing?

Codex Desktop on Windows is ignoring mcp_servers.node_repl config.

Environment:

• Windows
• Codex app path: C:\Program Files\WindowsApps\OpenAI.Codex_26.519.10634.0_x64__2p2nqsd0c76g0
• Workspace: C:\Users\dkxha\OneDrive\문서\Max Leak Detection Website

Problem: The JavaScript / node_repl runtime fails immediately with:

windows sandbox failed: spawn setup refresh reason: stdout_eof

I updated C:\Users\dkxha.codex\config.toml:

[mcp_servers.node_repl] args = ["--disable-sandbox"] command = 'C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe'

After fully restarting Codex, node_repl.exe still launches without --disable-sandbox.

Verified with process command line: "C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe"

Expected: node_repl.exe should launch with --disable-sandbox.

Also tested wrapper workaround: command = 'C:\Users\dkxha.codex\node_repl\node_repl_wrapper.cmd' args = []

Codex still launched the original node_repl.exe directly, ignoring the configured command path.

Conclusion: mcp_servers.node_repl args and command appear to be ignored or overridden by an internal hardcoded launcher path.

What steps can reproduce the bug?

1. Use Codex Desktop on Windows.

2. Edit:

C:\Users\dkxha.codex\config.toml

1. Configure node_repl like this:

[mcp_servers.node_repl] args = ["--disable-sandbox"] command = 'C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe' startup_timeout_sec = 120

1. Fully quit Codex Desktop.

2. Reopen Codex Desktop.

3. Start a new thread in the same workspace.

4. Run a minimal JavaScript / node_repl smoke test:

nodeRepl.write('js-ok')

1. The node_repl runtime fails immediately with:

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

1. Check the live Windows process command line for node_repl.exe.

Observed command line:

"C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe"

Expected command line:

"C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe" --disable-sandbox

1. As an additional test, change config.toml to use a wrapper command:

[mcp_servers.node_repl] args = [] command = 'C:\Users\dkxha.codex\node_repl\node_repl_wrapper.cmd'

1. The wrapper contains:

@echo off "C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe" --disable-sandbox

1. Fully quit and reopen Codex again.

2. Run the same JavaScript / node_repl smoke test.

3. Codex still launches the original node_repl.exe directly instead of the configured wrapper command.

Observed result: mcp_servers.node_repl args and command appear to be ignored or overridden by an internal launcher path.

What is the expected behavior?

Codex Desktop should respect the configured MCP server command and arguments in C:\Users\dkxha.codex\config.toml.

When this config is present:

[mcp_servers.node_repl] args = ["--disable-sandbox"] command = 'C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe'

Codex should launch node_repl.exe with the configured argument:

node_repl.exe --disable-sandbox

If the command path is changed to a wrapper script, Codex should launch that configured wrapper command instead of continuing to launch the original node_repl.exe path.

The JavaScript runtime should start successfully, and Chrome/browser automation that depends on node_repl should be able to connect.

Additional information

This blocks Chrome/browser automation because the JavaScript runtime fails before Chrome can be tested.

Observed runtime error:

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

I verified the live process command line after restarting Codex. Even though config.toml contains args = ["--disable-sandbox"], the actual process command line was:

"C:\Users\dkxha\AppData\Local\OpenAI\Codex\bin\3c238e29bbc930ff\node_repl.exe"

The --disable-sandbox argument was not present.

I also tested a wrapper workaround:

[mcp_servers.node_repl] args = [] command = 'C:\Users\dkxha.codex\node_repl\node_repl_wrapper.cmd'

The wrapper script ran the original executable with --disable-sandbox, but after restart Codex still launched the original node_repl.exe directly instead of the configured wrapper command.

This suggests mcp_servers.node_repl args and command are ignored or overridden by an internal launcher path in Codex Desktop on Windows.