I’ve found unexpected success in using ephemeral NixOS VMs for local development… once you authenticate your agent you can let it run wild without worrying about permissions.

I got halfway thru learning about containers before I realized, I just don't want it to blow up my files. That was a very solved problem in the 1970s! So I just made a Linux user called agent.

Dies the agent have access to is own nix config (and therefore install permissions), or do you have to provide it all the tools externally?

It doesn’t even need access to nix config. It could use nix shell to grab the tools it needs.