Windows elevated sandbox breaks node_repl and Browser Runtime

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

26.527.31326

What subscription do you have?

Plus

What platform is your computer?

Microsoft Windows NT 10.0.26200.0 x64

What issue are you seeing?

When Codex Desktop is configured with:

[windows]
sandbox = "elevated"

the node_repl kernel fails before executing any user JavaScript.

Minimal test:

nodeRepl.write("ok");

fails with:

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

Because Browser Runtime depends on node_repl, browser automation is also unavailable.

What steps can reproduce the bug?

1. Configure Codex Desktop:

sandbox_mode = "danger-full-access"

[windows]
sandbox = "elevated"

1. Restart Codex Desktop.

1. Execute:

nodeRepl.write("ok");

1. Observe:

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

Additional confirmation:

Changing

[windows]
sandbox = "unelevated"

and restarting Codex Desktop makes node_repl work again.

What is the expected behavior?

node_repl should start successfully and execute JavaScript regardless of whether Windows sandbox mode is set to elevated or unelevated.

The following call should return successfully:

nodeRepl.write("ok");

Browser Runtime should remain operational because it depends on node_repl.

Additional information

Confirmed workaround:

[windows]
sandbox = "unelevated"

After switching to unelevated and restarting Codex Desktop:

nodeRepl.write(JSON.stringify({ ok: true, cwd: nodeRepl.cwd }));

returns:

{"ok":true,"cwd":"D:\\Antigravity\\IronHill"}

Browser Runtime also becomes functional again.

Additional observations:

• Codex-spawned environments contained both PATH and Path variables.
• PowerShell Env provider reported:

"An item with the same key has already been added."

• Attempting:

[mcp_servers.node_repl]
args = ["--disable-sandbox"]

did not affect the actual node_repl.exe command line.

A detailed diagnostic report is attached.

codex-windows-elevated-sandbox-node-repl-report.md