HISR: Hindsight Information Modulated Segmental Process Rewards For Multi-turn Agentic Reinforcement Learning

Fuente: arXiv
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Main Authors: Lu, Zhicong, Lin, Zichuan, Jia, Wei, Tian, Changyuan, Ye, Deheng, Li, Peiguang, Jin, Li, Liu, Nayu, Xu, Guangluan, Feng, Wei
Format: Preprint
Published: 2026
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_version_ 1866912973934559232
author Lu, Zhicong
Lin, Zichuan
Jia, Wei
Tian, Changyuan
Ye, Deheng
Li, Peiguang
Jin, Li
Liu, Nayu
Xu, Guangluan
Feng, Wei
author_facet Lu, Zhicong
Lin, Zichuan
Jia, Wei
Tian, Changyuan
Ye, Deheng
Li, Peiguang
Jin, Li
Liu, Nayu
Xu, Guangluan
Feng, Wei
contents While large language models excel in diverse domains, their performance on complex longhorizon agentic decision-making tasks remains limited. Most existing methods concentrate on designing effective reward models (RMs) to advance performance via multi-turn reinforcement learning. However, they suffer from delayed propagation in sparse outcome rewards and unreliable credit assignment with potentially overly fine-grained and unfocused turnlevel process rewards. In this paper, we propose (HISR) exploiting Hindsight Information to modulate Segmental process Rewards, which closely aligns rewards with sub-goals and underscores significant segments to enhance the reliability of credit assignment. Specifically, a segment-level process RM is presented to assign rewards for each sub-goal in the task, avoiding excessively granular allocation to turns. To emphasize significant segments in the trajectory, a hindsight model is devised to reflect the preference of performing a certain action after knowing the trajectory outcome. With this characteristic, we design the ratios of sequence likelihoods between hindsight and policy model to measure action importance. The ratios are subsequently employed to aggregate segment importance scores, which in turn modulate segmental process rewards, enhancing credit assignment reliability. Extensive experimental results on three publicly benchmarks demonstrate the validity of our method.
format Preprint
id arxiv_https___arxiv_org_abs_2603_18683
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle HISR: Hindsight Information Modulated Segmental Process Rewards For Multi-turn Agentic Reinforcement Learning
Lu, Zhicong
Lin, Zichuan
Jia, Wei
Tian, Changyuan
Ye, Deheng
Li, Peiguang
Jin, Li
Liu, Nayu
Xu, Guangluan
Feng, Wei
Machine Learning
Artificial Intelligence
Computation and Language
While large language models excel in diverse domains, their performance on complex longhorizon agentic decision-making tasks remains limited. Most existing methods concentrate on designing effective reward models (RMs) to advance performance via multi-turn reinforcement learning. However, they suffer from delayed propagation in sparse outcome rewards and unreliable credit assignment with potentially overly fine-grained and unfocused turnlevel process rewards. In this paper, we propose (HISR) exploiting Hindsight Information to modulate Segmental process Rewards, which closely aligns rewards with sub-goals and underscores significant segments to enhance the reliability of credit assignment. Specifically, a segment-level process RM is presented to assign rewards for each sub-goal in the task, avoiding excessively granular allocation to turns. To emphasize significant segments in the trajectory, a hindsight model is devised to reflect the preference of performing a certain action after knowing the trajectory outcome. With this characteristic, we design the ratios of sequence likelihoods between hindsight and policy model to measure action importance. The ratios are subsequently employed to aggregate segment importance scores, which in turn modulate segmental process rewards, enhancing credit assignment reliability. Extensive experimental results on three publicly benchmarks demonstrate the validity of our method.
title HISR: Hindsight Information Modulated Segmental Process Rewards For Multi-turn Agentic Reinforcement Learning
topic Machine Learning
Artificial Intelligence
Computation and Language
url https://arxiv.org/abs/2603.18683