Cursor admits coding model built on Moonshot AI's Kimi

AI coding company Cursor has acknowledged that its new Composer 2 model was initially built upon Moonshot AI's open-source Kimi 2.5 model. This admission followed claims that Composer 2 was essentially Kimi with added reinforcement learning. Cursor's VP of developer education confirmed that while Kimi served as the base, only about a quarter of the compute was used for the initial model, with the rest dedicated to Cursor's own training. He asserted that Composer 2's performance differs significantly from Kimi's and that its use complied with licensing terms, facilitated through a partnership with Fireworks AI.