ExpRL: Unified Non-Parametric and Parametric Experience Learning for LLM Agent Evolution

Zhuoran Jin, Lingshuai Wang, Yupu Hao, Tianyi Men, Zhitao He, Daojian Zeng, Kang Liu, Jun Zhao


Abstract
Large language model (LLM)-based agents solve complex long-horizon tasks through iterative interaction with environments, where effectively learning from experience under sparse or delayed feedback remains a key challenge. Existing approaches typically rely on either non-parametric memory-based experience reusing or parametric reinforcement learning, each with inherent limitations when used in isolation. To this end, we propose **ExpRL**, a unified experience learning framework that bridges non-parametric memory and parametric policy optimization for LLM agents. ExpRL induces abstracted success and failure experiences from on-policy interaction trajectories, stores them in an external memory, and integrates experience acquisition and utilization directly into the reinforcement learning process via an agentic experience acquisition mechanism. This design enables memory and policy to co-evolve and mutually reinforce each other, effectively unifying online policy learning with offline experience reuse. Experiments on ALFWorld and WebShop demonstrate that ExpRL achieves an average performance improvement of **13.0** over GRPO, with improved learning efficiency and stability. We further show that the induced experience memory generalizes across different models and can be directly transferred to stronger LLMs without additional training.
Anthology ID:
2026.findings-emnlp.1666
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
35524–35546
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.1666/
DOI:
Bibkey:
Cite (ACL):
Zhuoran Jin, Lingshuai Wang, Yupu Hao, Tianyi Men, Zhitao He, Daojian Zeng, Kang Liu, and Jun Zhao. 2026. ExpRL: Unified Non-Parametric and Parametric Experience Learning for LLM Agent Evolution. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 35524–35546, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
ExpRL: Unified Non-Parametric and Parametric Experience Learning for LLM Agent Evolution (Jin et al., Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.1666.pdf