Beyond Retrieval: Bi-Temporal State Arbitration for Longitudinal Healthcare Agents

Jianing Zhao, Xiaoquan Zhi, Xinqiang Yu


Abstract
Longitudinal healthcare agents require persistent state tracking under temporal uncertainty. In domains like chronic disease management, patient states—medications, symptoms, and vital signs—evolve continuously over months. Existing memory architectures for Large Language Models (LLMs) are inherently retrieval-centric: they treat memory as a static repository of past interactions, failing to resolve conflicting or superseded information when queried for the current patient state. We propose a shift to state-centric memory. Our framework introduces (1) a bi-temporal state representation that decouples event time from ingestion time and tracks temporal validity windows, (2) an incremental state arbitration mechanism using four operators—SUPPORT, REFINE, SUPERSEDE, and BRANCH-CONFLICT—to handle evolving medical facts without destructive overwriting, and (3) a confidence-thresholded evidence escalation layer for robust, efficient memory access. Evaluated on a longitudinal diabetes management suite as a representative biomedical state tracking task, our method achieves a Unique-F1 of 0.85 and Conflict-F1 of 0.98, substantially improves upon long-context LLMs (0.38 / 0.89) and standard vector memory (0.30 / 0.60), demonstrating that agentic AI in longitudinal biomedical settings requires continuous, evidence-grounded arbitration rather than simple retrieval.
Anthology ID:
2026.knowfm-1.10
Volume:
Proceedings of the 4th Workshop on Towards Knowledgeable Foundation Models (KnowFM 2026)
Month:
July
Year:
2026
Address:
San Diego, California, United States
Editors:
Canyu Chen, Yuji Zhang, Zoey Sha Li, Zihan Wang, Qineng Wang, Jinyan Su, Priyanka Kargupta, Sara Vera Marjanović, Jeff Z. Pan, Mohit Bansal, Isabelle Augenstein, Jiawei Han, Heng Ji, Manling Li
Venues:
KnowFM | WS
SIG:
Publisher:
Association for Computational Linguistics
Note:
Pages:
129–137
Language:
URL:
https://preview.aclanthology.org/ingest-acl-workshops/2026.knowfm-1.10/
DOI:
Bibkey:
Cite (ACL):
Jianing Zhao, Xiaoquan Zhi, and Xinqiang Yu. 2026. Beyond Retrieval: Bi-Temporal State Arbitration for Longitudinal Healthcare Agents. In Proceedings of the 4th Workshop on Towards Knowledgeable Foundation Models (KnowFM 2026), pages 129–137, San Diego, California, United States. Association for Computational Linguistics.
Cite (Informal):
Beyond Retrieval: Bi-Temporal State Arbitration for Longitudinal Healthcare Agents (Zhao et al., KnowFM 2026)
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PDF:
https://preview.aclanthology.org/ingest-acl-workshops/2026.knowfm-1.10.pdf