Composer 2.5 is now available in Cursor.
It's a substantial improvement in intelligence and behavior over Composer 2. It is better at sustained work on long-running tasks, follows complex instructions more reliably, and is more pleasant to collaborate with.
We improved Composer by scaling training, generating more complex RL environments, and introducing new learning methods.
In addition to training Composer 2.5 on more difficult tasks, we improved behavioral aspects of the model like communication style and effort calibration. These dimensions are not well captured by existing benchmarks, but we find that they matter for real-world usefulness.
Composer 2.5 is built on the same open-source checkpoint as Composer 2, Moonshot's Kimi K2.5.
