Synthesizing Post-Training Data for LLMs through Multi-Agent Simulation
Shuo Tang, Xianghe Pang, Zexi Liu, Bohan Tang, Rui Ye, Tian Jin, Xiaowen Dong, Yanfeng Wang, Siheng Chen
TL;DR
The paper introduces MATRIX, a large-scale multi-agent simulator that grounds synthetic data in realistic, real-world-like scenarios, coupled with MATRIX-Gen, a scenario-driven instruction generator for post-training data. By simulating diverse agent interactions and leveraging scenario contexts, the framework produces high-quality SFT, DPO, reasoning, and domain-specific data. Empirical results show that models trained with as few as 20K MATRIX-Gen samples can outperform models trained on orders of magnitude more data on benchmarks like AlpacaEval 2 and Arena-Hard, underscoring the practical impact of grounded, scalable data synthesis. The work highlights scalability and realism as key levers for improving instruction-following capabilities while noting computational cost as a current limitation and avenue for future optimization.
Abstract
Post-training is essential for enabling large language models (LLMs) to follow human instructions. However, its effectiveness depends on high-quality instruction data, which is challenging to obtain in the real world due to privacy concerns, data scarcity, and high annotation costs. To fill this gap, inspired by the recent success of using LLMs to simulate human society, we propose MATRIX, a multi-agent simulator that automatically generates diverse text-based scenarios, capturing a wide range of real-world human needs in a realistic and scalable manner. Leveraging these outputs, we introduce a novel scenario-driven instruction generator MATRIX-Gen for controllable and highly realistic data synthesis. Extensive experiments demonstrate that our framework effectively generates both general and domain-specific data. On AlpacaEval 2 and Arena-Hard benchmarks, Llama-3-8B-Base, post-trained on datasets synthesized by MATRIX-Gen with just 20K instruction-response pairs, outperforms Meta's Llama-3-8B-Instruct model, which was trained on over 10M pairs.
