AtomMem: Building Simple and Effective Memory System for LLM Agents via Atomic Facts

Yanyu Yao, Shangze Li, Zhi Zheng, Hui Zheng, Qi Liu, Tong Xu, Enhong Chen


Abstract
Large language models (LLMs) demonstrate strong reasoning and generation abilities, but their fixed context windows limit long-term information accumulation and reuse across multi-session interactions. Existing memory-augmented systems often construct memory in a coarse and unstable manner, relying on inefficient memory representations or unstable unconstrained updates. To address these challenges, we propose **AtomMem**, a long-term memory system designed for value-dense storage and stable memory evolution. AtomMem introduces a Fact Executor, which selectively extracts high value atomic facts from long form interactions to serve as highly efficient memory representations. Subsequently, AtomMem organizes these facts into hierarchical event structures and temporal profiles, capturing coherent episodic contexts and tracking dynamically evolving user attributes over time. During retrieval, the system activates an associative memory graph to connect fragmented memories. Experiments on the LoCoMo benchmark confirm that AtomMem achieves state-of-the-art performance across various reasoning tasks, offering a scalable and economically viable solution for deploying intelligent personalized agents. The implementation code is publicly available at [https://github.com/MINE-USTC/AtomMem](https://github.com/MINE-USTC/AtomMem).
Anthology ID:
2026.emnlp-main.2387
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:
54243–54265
Language:
URL:
https://aclanthology.org/2026.emnlp-main.2387/
DOI:
Bibkey:
Cite (ACL):
Yanyu Yao, Shangze Li, Zhi Zheng, Hui Zheng, Qi Liu, Tong Xu, and Enhong Chen. 2026. AtomMem: Building Simple and Effective Memory System for LLM Agents via Atomic Facts. In Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing, pages 54243–54265, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
AtomMem: Building Simple and Effective Memory System for LLM Agents via Atomic Facts (Yao et al., EMNLP 2026)
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PDF:
https://aclanthology.org/2026.emnlp-main.2387.pdf