For me, the success is having a simple way to prompt an Agent AI to modify my NixOS desktop and get live feedback.

It can use the above MCP to search NixOS options and packages for me and make recommendations and edit the actual files, rebuild, etc.

It can then use nix flake check and other commands to verify the work it does actually did what was expected.

Even if there is still a bad result from time to time, I find this pretty valuable!