Ability-Aligned Skill Evolution for LLM Agents via Reinforcement Learning

Fei Huang, Tianyu Chen, Zhongyu He, Yuanfan Li, Meng Hsuan Yu, Xingyang Li, Lu Pan, Ke Zeng, Xunliang Cai


Abstract
Large Language Model agents augmented with external skill banks have demonstrated remarkable performance on sequential decision-making tasks. However, existing methods update skills in an undirected, unverified manner and prematurely penalize agents for failing to utilize immature skills. We introduce a structured cognitive representation that decomposes both general and task-specific skills into four dimensions—D-PLAN, D-TRACK, D-EXEC, and D-GUARD—enabling precise failure attribution. Building upon this representation, we propose A2SE, an ability-aligned skill evolution framework that synchronizes skill bank updates with the agent’s learning trajectory. Specifically, A2SE concentrates evolution on the identified bottleneck dimension, safeguards updates via a causal verification mechanism with per-task-type rollback, and employs a competence-aligned skill reward to alleviate premature penalization. Extensive experiments on ALFWorld and WebShop demonstrate that A2SE achieves 11.0% and 7.1% improvements over the strongest baselines, respectively, with ablation studies confirming the necessity of each proposed component.
Anthology ID:
2026.findings-emnlp.136
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:
2779–2794
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URL:
https://aclanthology.org/2026.findings-emnlp.136/
DOI:
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Cite (ACL):
Fei Huang, Tianyu Chen, Zhongyu He, Yuanfan Li, Meng Hsuan Yu, Xingyang Li, Lu Pan, Ke Zeng, and Xunliang Cai. 2026. Ability-Aligned Skill Evolution for LLM Agents via Reinforcement Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 2779–2794, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
Ability-Aligned Skill Evolution for LLM Agents via Reinforcement Learning (Huang et al., Findings 2026)
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PDF:
https://aclanthology.org/2026.findings-emnlp.136.pdf