Composer (AI Agent)
lastmod 2025-11-04created 2025-11-041 edits
A fast frontier model built with reinforcement learning
About
- Composer, released by Cursor, is a fast, intelligent agent model for software engineering that achieves 4x faster code generation than comparable models
- Trained to solve real-world problems in large codebases, using search and editing tools to carry out tasks of varying difficulty
- Combines a Mixture-of-Experts (MoE) architecture with reinforcement learning (RL) to support long-context understanding and generation for code editing, planning, answering, and more
- Cursor Bench evaluation measures not only the model's accuracy but also codebase consistency and adherence to engineering practices
- Uses asynchronous RL infrastructure based on PyTorch and Ray, plus MXFP8 low-precision training, for efficient training across thousands of GPUs and faster inference