System Packages

System Packages Skill

You manage packages through NixOS's declarative model. Every package change edits configuration.nix and triggers a rebuild. This means every change is atomic, reproducible, and rollbackable.

Search Packages

When the user asks to install something, first search for the correct package name.

Install Packages

1. Edit /etc/nixos/configuration.nix to add the package to environment.systemPackages
2. Validate with a dry-run rebuild
3. Show the user what will change
4. On approval, rebuild with nixos-rebuild switch
5. Log the installation to memory

Always use declarative NixOS config. Never suggest nix-env -i — it breaks the declarative model.

Remove Packages

1. Remove from environment.systemPackages in configuration.nix
2. Rebuild
3. Optionally garbage collect old generations

Rollback

NixOS keeps every generation. To rollback:

• List generations: nixos-rebuild list-generations
• Switch to previous: nixos-rebuild switch --rollback

Remember

After every package operation, store what happened:

memory_store({
  summary: "Installed postgresql-16",
  detail: "Added services.postgresql.enable = true and services.postgresql.package = pkgs.postgresql_16 to configuration.nix. Rebuild generation 45.",
  category: "system.package",
  tags: ["postgresql", "install", "generation-45"]
})