SWEET-RL: Training Multi-Turn LLM Agents on Collaborative Reasoning
  Tasks
Authors: name: Yifei Zhou; name: Song Jiang; name: Yuandong Tian; name: Jason Weston; name: Sergey Levine; name: Sainbayar Sukhbaatar; name: Xian Li
Published: 2025-03-19 17:55:08

Abstract: Large language model (LLM) agents need to perform multi-turn interactions in
real-world tasks. However, existing multi-turn RL algorithms for optimizing LLM
agents fail to perform effective credit assignment over multiple turns while
leveraging the generalization capabilities of LLMs and it remains unclear how
to develop such algorithms. To study this, we first introduce a new benchmark,
ColBench, where an LLM agent interacts with a human collaborator over multiple
turns to solve realistic tasks in backend programming and frontend design.
Building on this benchmark, we propose a novel RL algorithm, SWEET-RL (RL with
Step-WisE Evaluation from Training-time information), that uses a carefully
designed optimization objective to train a critic model with access to
additional training-time information. The critic provides step-level rewards
for improving the policy model. Our experiments demonstrate that SWEET-RL
achieves a 6% absolute improvement in success and win rates on ColBench
compared to other state-of-the-art multi-turn RL algorithms, enabling
Llama-3.1-8B to match or exceed the performance of GPT4-o in realistic
collaborative content creation.