diff --git a/flake.nix b/flake.nix
index 9f1a90d..1bf17c7 100644
--- a/flake.nix
+++ b/flake.nix
@@ -10,9 +10,16 @@
     flake-utils.lib.eachDefaultSystem
       (system:
         let
-          pkgs = nixpkgs.legacyPackages.${system};
+          pkgs = nixpkgs.legacyPackages.${system}.extend overlay;
           ros = ros-flake.legacyPackages.${system};
 
+          overlay = final: prev: {
+            # -- PLACEHOLDER for overlay
+            # freecad = prev.freecad.overrideAttrs
+            #   (old: { cmakeFlags = old.cmakeFlags ++ [ "-DBUILD_GUI=OFF" ]; });
+            # cmakeFlag -BUILD_GUI=OFF for build without gui
+          };
+
           # overrided packages and attributes for nix-ros-overlay
           humble-overrided = ros.humble.overrideScope (final: prev: {
             # remove after update github:lopsided98/nixpkgs/nix-ros for https://github.com/NixOS/nixpkgs/pull/224099