{ lib, ... }: with lib; { config.outputKinds = [ ( { hasSystem, ... }: optionalAttrs hasSystem { options = { devShells = mkOption { type = with types; attrsOf package; description = "Used by `nix develop .#`"; }; }; outputs = { config, system, ... }: { devShells.${system} = config.devShells; }; } ) ]; }