Ask Only When Needed: Proactive Retrieval from Memory and Skills for Experience-Driven Lifelong Agents

Yuxuan Cai, Wei Li, Jie Zhou, Qin Chen, Xin Li, Bo Zhang, Liang He


Abstract
Online lifelong learning agents must decide not only how to act but also when to consult prior experience to continually improve on long-horizon tasks. Existing methods typically retrieve memories passively, such as at task initialization or after each step, and therefore miss knowledge gaps that arise during interaction. We propose ProactAgent, an experience-driven lifelong learning framework for proactive retrieval over a structured Experience Base. ProactAgent continually improves through ExpOnEvo, which jointly updates policies and refines memory, organizing past interactions into factual, episodic, and skill repositories. It further introduces ProactRL, which treats retrieval as an explicit policy action and learns when and what to retrieve. By comparing paired continuations from identical interaction prefixes with and without retrieval, ProactRL provides step-level process rewards that encourage retrieval only when it improves task outcomes or efficiency. Experiments on SciWorld, AlfWorld, and StuLife show that ProactAgent consistently outperforms all baselines, achieving up to 32% relative improvement in success rate and over 33% reduction in interaction rounds.
Anthology ID:
2026.findings-emnlp.775
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:
16384–16400
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.775/
DOI:
Bibkey:
Cite (ACL):
Yuxuan Cai, Wei Li, Jie Zhou, Qin Chen, Xin Li, Bo Zhang, and Liang He. 2026. Ask Only When Needed: Proactive Retrieval from Memory and Skills for Experience-Driven Lifelong Agents. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 16384–16400, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Ask Only When Needed: Proactive Retrieval from Memory and Skills for Experience-Driven Lifelong Agents (Cai et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.775.pdf