Custom instructions are incorrectly shared across Chat, Codex, and Work

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

26.721.31836

What subscription do you have?

Plus

What platform is your computer?

Darwin 25.5.0 arm64 arm

What issue are you seeing?

In the previous ChatGPT app, custom instructions under:

Settings > Personalization > Custom Instructions

applied only to Chat.

In the new merged ChatGPT/Codex app, these instructions are written to:

~/.codex/AGENTS.md

and are then applied to Chat, Codex, and Work.

This is incorrect because chat instructions and coding-agent instructions have different purposes and may conflict.

What steps can reproduce the bug?

Feedback ID: no-active-thread-019f9499-a5ff-7630-a944-e1e41253ce78

What is the expected behavior?

Expected behavior:

• Chat instructions should apply only to Chat.
• Codex instructions should remain separate.
• Work instructions should remain separate.
• Global instructions should be optional and explicitly configured.

Existing ChatGPT custom instructions should not automatically be stored in ~/.codex/AGENTS.md.

Additional information

_No response_