Changing system configuration from home?

First, I am aware that this can not be done directly and it's not what I'm asking for.

I would like a way of checking homeConfigurations from the nixosConfigurations side. The goal would be, to for example check if a user has a DE enabled, so that it can be added to system packages in the nixosConfiguration.

I haveoctelly.programs.mpv.enable = true; in homes/x86_64-linux/octelly@vmware-nixos (test option). I've done some probing and found that:

• loading the flake in repl and checking nixosConfigurations.vmware-nixos.config.snowfallorg.users.octelly.home.config.octelly.programs.mpv.enable returns false
• loading the flake in repl and checking homeConfigurations."octelly@vmware-nixos".options.octelly.programs.mpv.enable.value, however I'm not aware of a documented way of accessing self

I thought of writing per-user NixOS modules, so that a system could set options like target.graphics = true; and users could have their modules that would then for example snowfallorg.users.octelly.home.config.programs.plasma = true;, but that feels like a dirty fix.

Start by loading the flake in a Nix REPL and compare the homeConfigurations and nixosConfigurations expressions described in the issue. Investigate how the home configuration is exposed through snowfallorg.users and determine a documented way for the system side to inspect it. Done means the cross-configuration access pattern is defined and demonstrated for the octelly home configuration.