Don't install kanshi on non-graphical installs.

nix/configuration/roles/kanshi/default.nix

@@ -17,6 +17,22 @@ in
 {
   imports = [ ];
 
+  options.me = {
+    kanshi.enable = lib.mkOption {
+      type = lib.types.bool;
+      default = false;
+      example = true;
+      description = "Whether we want to install kanshi.";
+    };
+  };
+
+  config = lib.mkIf config.me.kanshi.enable (
+    lib.mkMerge [
+      {
+        environment.systemPackages = with pkgs; [
+        ];
+      }
+      (lib.mkIf config.me.graphical {
         environment.systemPackages = with pkgs; [
           kanshi
         ];
@@ -34,4 +50,7 @@ in
               };
             };
           };
+      })
+    ]
+  );
 }