Create a file media/lua/client/<yourmodid>_necroForgeSupport.lua with the following content: Events.OnGameStart.Add( function () print ("Adding NecroForge for <myModID>"); if NecroList then if not NecroList.Items.FooBarItem then NecroList.Items.FooBarItem = {"Misc.", nil, nil, "Foobar item", "itemmodule.itemid", "FoobarItemTexture", nil, nil, nil}; end endendFor a more thorough example you can check how I did it with the spraypaint mod: https://github.com/blind-coder/pz-spraypaint/blob/master/media/lua/client/spraypaint_necroForgeSupport.lua Kind of figured it out already, but thank anyway