Y’all may already know this, but I just found out today… in Codex you can assign multiple folders to a project.
I have been working on a desktop client and a web app server combo and having to copy prompts back and forth between my two Codex projects to keep things aligned. But once I realized I could give one Codex project access to multiple folders and a little instruction that they were separate but related apps, it was free to make the needed changes in both with my only input being switching the active project in the IDE when needed.
It made me happy.