Codex Windows sandbox warning is transient, non-actionable, and causes silent Git failures

What version of the VS Code extension are you using?

0.4.60

What subscription do you have?

Plus

Which IDE are you using?

VS Code

What platform is your computer?

Windows

What issue are you seeing?

Title: Codex Windows sandbox warning is transient, non-actionable, and causes silent Git failures

Environment:

• Windows
• VS Code
• Codex extension
• Repo not in WSL / Remote containers

Problem:
Codex was running with the experimental Windows sandbox enabled by default.
The ONLY indication was a brief, flashing warning:

“enable_experimental_windows_sandbox is deprecated. Use [features].experimental_windows_sandbox instead.”

The warning:

• appears for only a moment
• does not explain impact
• does not tell the user where the config file is
• does not say that Codex is running in a sandbox
• is nearly impossible to notice or capture

Symptoms:

• Codex repeatedly failed git add / git commit with:

.git/index.lock: Permission denied

• VS Code Git and Copilot worked fine in the same repo
• Codex itself could not identify or diagnose the issue

Root cause (after hours of debugging):

• Codex’s experimental Windows sandbox interferes with Git lockfile creation
• Disabling it via:

C:\Users\<user>\.codex\config.toml
[features]
experimental_windows_sandbox = false
immediately resolved the issue

Why this is serious:

• The sandbox materially changes filesystem semantics
• Git failures look like OneDrive / permissions / AV issues
• Users have no discoverable way to know they are sandboxed
• The warning is ephemeral and non-actionable

Requested improvements:

1. Persistent, visible indicator when Codex is running in Windows sandbox mode
2. Warning that explicitly mentions filesystem/Git implications
3. Clear instruction on where the config file lives
4. Either disable the sandbox by default or provide an obvious toggle in settings
5. Codex diagnostics command that reports runtime mode (native vs sandbox)

This issue cost several hours of debugging time and was extremely difficult to diagnose.

What steps can reproduce the bug?

A toml file that wasn't manually edited.

What is the expected behavior?

Easy to see warning with a solution that Codex can fix.

Additional information

_No response_