Copilot CLI prompts for /dev/null access in non-interactive CI environment

[john-james-gh]

Describe the bug

When running Copilot CLI inside CI (non-interactive), it occasionally prompts for access to /dev/null, which makes no sense in this context since there’s no user to respond. This causes the job to hang indefinitely.

✓ List directory . (32 files)
✓ Read package.json (74 lines)

The following paths are outside the allowed directories:
/dev/null | wc -l
Allow access to these paths? (y/n):

The following paths are outside the allowed directories:
/dev/null | head -20
Allow access to these paths? (y/n):

Affected version

0.0.350 Commit: 6bd4106

Steps to reproduce the behavior

Run Copilot CLI inside a CI job (GitHub Actions in my case).

Configure access only to the current repository (as recommended in the docs).

  copilot \
  --model claude-sonnet-4.5 \
  --allow-all-tools \
  --deny-tool 'shell(git push)' \
  --deny-tool 'write' \
  --add-dir "$GITHUB_WORKSPACE" \

Trigger any command that scans files (e.g., copilot suggest, copilot test, etc.).

Observe that it hangs waiting for input about /dev/null.

Expected behavior

Copilot CLI should not attempt to request access to /dev/null, nor prompt for confirmation in non-interactive mode.
/dev/null should not be treated as a file path outside the allowed directories. It’s a standard system sink, not part of the project.

Additional context

It looks like the CLI is interpreting /dev/null as a regular file path when running shell commands like wc -l or head -20. This likely causes the access control layer to treat it as an “external” path and prompt for approval, even though /dev/null is safe and should be ignored or auto-allowed.

Environment: GitHub Actions (Ubuntu runner latest)

[shawnau]

same issue here. it blocks us from using it in automated workflow

[zerozedsc]

I am experiencing the same issue when using the GitHub Copilot extension. It always tries to write to /dev/null, which causes auto approval to malfunction and blocks most write requests. Has anyone found a fix or a way to bypass this issue?

[cstavaru]

This problem is pretty much all that is keeping GitHub Copilot from performing tasks without user interaction. All other interaction types can be pre-approved. Some kind of custom instructions to not redirect to /dev/null may be able to mitigate the problem until it is solved, but I haven't tried it yet.