fx is Vercel's tiny, open-source coding agent built to get out of your way. Because it is written in Zig and ships as a native binary about 6MB in game, it starts almost instantly and keeps memory and bandwidth very low. You can run it with local or cloud models, extend it with skills, plugins, and MCPs, or embed it into your own agent infrastructure. It is small by design, which gives the model more room and you a lighter tool to work with.
Launch Date:
August 25, 2026