Distributed RL Let Composer Match Frontier Coding Models With Smaller-Model Speed
Cursor’s Federico Cassano and Fireworks’ Dmytro Dzhulgakov argue that Composer’s advantage comes from specializing a model for software engineering inside Cursor rather than spending capacity on general-purpose behavior. Starting from an open-source base, Cursor used mid-training and reinforcement learning against its own product environment, while Fireworks supplied the distributed infrastructure needed to make agent rollouts, weight synchronization, and inference efficient enough to run at scale. Their case is that application companies with enough product-specific usage, tools, and feedback can build models that are better, faster, and cheaper for their own workflows than larger general models.
Sequoia Capital·May 26, 2026·17 min read