ChatGPT Projects are kind of like folders that you can use to organize different elements of a, you guessed it, project. Things like chats and attachments can be segmented from each other and from the main chat space.
You don’t have to isolate things. If you want to, though, there’s a catch that can be easy to miss.
The feature is called memory, and it is similar to the memory feature in the main chat. In short, it can “remember” things that aren’t in the immediate chat (I think that behind the scenes, it is just programmed to look in an additional location to get the memory context but I can’t prove that).
If you want a project’s memory to be isolated, you must set it when you first create the project.
Select New project from the menu on the left
This will open a Project name window. Click on the gear icon to open the memory setting menu
Select project-only to keep memories isolated to this project
Add a name and select Create project
That’s it! Now, when you chat within this project, everything will be isolated and not accessible from other projects, custom GPTs, or the main chat area.
Note that if you don’t set this when you create a project, it will be greyed out and you won’t be able to change it later. The only way that I’ve found to deal with this is to delete the project and create a new one.