Introducing Composer 1.5

Composer 1.5 is released, striking a strong balance between speed and intelligence for daily use. It was built by scaling reinforcement learning 20x further on the same pretrained model, with post-training compute surpassing the pretraining of the base model. Improvements are most significant on challenging tasks, measured by an internal benchmark of real-world coding problems. Composer 1.5 is a thinking model that generates thinking tokens to reason about the user's codebase and plan next steps, responding quickly on easy problems with minimal thinking and thinking until a satisfying answer is found on hard problems. It also has the ability to self-summarize to handle longer running tasks and continue exploring for a solution when context runs out, maintaining accuracy as context length varies. Its training demonstrates that RL for coding can be continually scaled with predictable intelligence improvements.