Mod Constructor is an advanced tool to create XML mods for The Sims 4. The current version focuses on making traits, and offers far more features than Buff and Trait Factory, including buff replacements, buffs that are always active under certain conditions, proximity buffs, and more.
Mods created in Mod Constructor are made up of a tree of resources and component that can interact with each other to generate code that will be exported to the game.
Although the first version focuses on traits, future versions will further expand options to allow the creation of social events, aspirations, interactions, careers and more.
Mod Constructor is currently available in beta form, with updates planned for the future. You can download the tool here: http://zerbu.tumblr.com/post/137431730692/the-sims-4-mod-constructor-beta