ACLs aren't even the issue here, first you need an entity separate from "the current user" to grant that access to. That's what jails, sandboxes or capability-based systems bring to the table. But you have to use them, most of those AI tools and their IDE integrations don't. Once you have those you can think about which access to grant that entity.

What do you find hard about it? Is it a conceptual thing or the tools themselves? I'm very far from a sysadmin, but it's just such a ground level using-linux type thing in my brain, I don't think I ever thought I had a choice about learning it!

Owner/Group/World rwx permissions are ground-level. I'm not sure I'd put ACLs, or SELinux, or AppArmor in the same sphere. Those start of at "arcane" and then get more complicated, at least that's my impression, and I've used linux for decades.