I like the bubblewrap approach, it just happens to be Linux-only unfortunately. And once privileges are dropped for a process it doesn't appear to be possible to reinstate them.
> once privileges are dropped [...] it doesn't appear to be possible to reinstate them
I don't understand. If unprivileged code could easily re-elevate itself, privilege dropping would be meaningless ...
If you need to communicate with the outside, you can do so via sockets (such as the bind-mounted X11 socket in one of the readme Examples).
I happen to use a Mac, even when targeting Linux so I'd have to use a container or VM anyways. It's nice how lightweight bubblewrap would be however.
Consider one wanted to replicate the human-approval workflow that most agent harnesses offer. It's not obvious to me how that could be accomplished by dropping privileges without an escape hatch.
IIRC from a comment in another thread, it's marked as deprecated to stop people from using it directly and to use the offical macOS tools directly. But it's still used internally by macOS.
