OptiMAS: Automatically Optimize Multi-Agent System

Yuxin Cheng, Chang Liu, Hanxin Yu, Haochen Tan, Taiqiang Wu, Weiqiang Jin, Jie Ran, Kaibo Wang, Xiaoguang Li, Haoli Bai, Graziano Chesi, Ngai Wong


Abstract
Automated evolution of Multi-Agent Systems (MAS) holds significant potential for reducing the manual effort required to design and optimize LLM-based agent architectures. However, extant search-based paradigms face a fundamental trade-off, where an expanded optimization scope exacerbates evolutionary instability, while discrete branch-and-discard search isolates insights across lineages. To address these limitations, we propose a continuous, data-driven optimization paradigm built upon a unified ReAct-based infrastructure that reconciles a broad optimization scope with operational stability. Under this paradigm, we present OptiMAS, a task-agnostic agentic optimizer that leverages textual interaction trajectories and task feedback as loss signals for end-to-end MAS evolution. Equipped with a novel dual-track memory mechanism, OptiMAS sustains performance improvement over extended optimization horizons. Evaluation on four heterogeneous agentic benchmarks with three varying scale and accessibility LLM backbones, demonstrates that OptiMAS consistently achieves competitive or superior accuracy relative to both domain-specialized hand-crafted systems and existing evolutionary methods. Our work establishes a practical milestone toward robust, automated MAS evolution.
Anthology ID:
2026.emnlp-main.470
Volume:
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
EMNLP
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
10794–10821
Language:
URL:
https://aclanthology.org/2026.emnlp-main.470/
DOI:
Bibkey:
Cite (ACL):
Yuxin Cheng, Chang Liu, Hanxin Yu, Haochen Tan, Taiqiang Wu, Weiqiang Jin, Jie Ran, Kaibo Wang, Xiaoguang Li, Haoli Bai, Graziano Chesi, and Ngai Wong. 2026. OptiMAS: Automatically Optimize Multi-Agent System. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 10794–10821, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
OptiMAS: Automatically Optimize Multi-Agent System (Cheng et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.470.pdf