Leaving the Past Behind: Breaking Personalization Inertia in Long-Term LLM Agents

Wenhao Yuan, Chenchen Lin, Jian Chen, Weijie Liu, Jinfeng Xu, Shuo Yang, Edith Cheuk-Han Ngai


Abstract
LLM agents rely on long-term interaction histories to tailor their responses to individual users. However, historical personalization signals may become stale or misaligned with expectations implied by the current context, leading agents to follow outdated preferences during reasoning. We refer to this failure mode as personalization inertia, which shifts the agent’s behavior away from the user’s current intent. Existing methods mainly optimize final responses or memory retrieval, leaving such failures underexplored. In this paper, we propose Personalization Inertia VerificatiOn and RegulaTion (Pivot), a framework for mitigating personalization inertia in long-term interactions with agents. Concretely, we construct a trajectory-independent evidence condition as a diagnostic reference, model prefix-evidence consistency to assess compatibility with the current personalization evidence, and learn a rollback policy to determine whether and where to intervene. The selected intervention triggers local repair, preserving the reliable prefix while regenerating only the potentially inertia-affected suffix under evidence-guided constraints. Experiments on benchmark datasets demonstrate consistent gains in personalization accuracy and trajectory faithfulness with targeted intervention overhead.
Anthology ID:
2026.findings-emnlp.1744
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
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SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
37311–37333
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URL:
https://aclanthology.org/2026.findings-emnlp.1744/
DOI:
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Cite (ACL):
Wenhao Yuan, Chenchen Lin, Jian Chen, Weijie Liu, Jinfeng Xu, Shuo Yang, and Edith Cheuk-Han Ngai. 2026. Leaving the Past Behind: Breaking Personalization Inertia in Long-Term LLM Agents. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 37311–37333, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Leaving the Past Behind: Breaking Personalization Inertia in Long-Term LLM Agents (Yuan et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.1744.pdf