VS Code extension creates refs/codex checkpoint refs that break SourceTree branch listing and fetch

What version of the IDE extension are you using?

26.609.30741

What subscription do you have?

chat gpt plus

Which IDE are you using?

VS code

What platform is your computer?

Microsoft Windows NT 10.0.26220.0 x64

What issue are you seeing?

When starting a Codex chat in VS Code extension, Codex creates refs like:

refs/codex/turn-diffs/checkpoints/...

These refs point to tree objects, not commits.

After that, SourceTree stops showing local branches and sometimes fetch fails with:

fatal: bad object refs/codex/...
error: did not send all necessary objects

Running this fixes SourceTree immediately:

git for-each-ref --format='delete %(refname)' refs/codex | git update-ref --stdin

What steps can reproduce the bug?

1. Open repo in VS Code with Codex extension.
2. Start a Codex chat.
3. Codex creates refs/codex/turn-diffs/checkpoints/... pointing to tree objects.
4. Open same repo in SourceTree.
5. Local branches disappear or fetch fails.

What is the expected behavior?

After starting a Codex chat, my repository should still work normally in SourceTree.

Local branches should still be visible, and fetch should work without errors.

Additional information

_No response_