T$^2$PO: Uncertainty-Guided Exploration Control for Stable Multi-Turn Agentic Reinforcement Learning

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Hauptverfasser: Wang, Haixin, Cui, Hejie, Zhang, Chenwei, Liu, Xin, Jin, Shuowei, Geng, Shijie, Zhang, Xinyang, Zalmout, Nasser, Shi, Zhenyu, Sun, Yizhou
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Veröffentlicht: 2026
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author Wang, Haixin
Cui, Hejie
Zhang, Chenwei
Liu, Xin
Jin, Shuowei
Geng, Shijie
Zhang, Xinyang
Zalmout, Nasser
Shi, Zhenyu
Sun, Yizhou
author_facet Wang, Haixin
Cui, Hejie
Zhang, Chenwei
Liu, Xin
Jin, Shuowei
Geng, Shijie
Zhang, Xinyang
Zalmout, Nasser
Shi, Zhenyu
Sun, Yizhou
contents Recent progress in multi-turn reinforcement learning (RL) has significantly improved reasoning LLMs' performances on complex interactive tasks. Despite advances in stabilization techniques such as fine-grained credit assignment and trajectory filtering, instability remains pervasive and often leads to training collapse. We argue that this instability stems from inefficient exploration in multi-turn settings, where policies continue to generate low-information actions that neither reduce uncertainty nor advance task progress. To address this issue, we propose Token- and Turn-level Policy Optimization (T$^2$PO), an uncertainty-aware framework that explicitly controls exploration at fine-grained levels. At the token level, T$^2$PO monitors uncertainty dynamics and triggers a thinking intervention once the marginal uncertainty change falls below a threshold. At the turn level, T$^2$PO identifies interactions with negligible exploration progress and dynamically resamples such turns to avoid wasted rollouts. We evaluate T$^2$PO in diverse environments, including WebShop, ALFWorld, and Search QA, demonstrating substantial gains in training stability and performance improvements with better exploration efficiency. Code is available at: https://github.com/WillDreamer/T2PO.
format Preprint
id arxiv_https___arxiv_org_abs_2605_02178
institution arXiv
publishDate 2026
record_format arxiv
spellingShingle T$^2$PO: Uncertainty-Guided Exploration Control for Stable Multi-Turn Agentic Reinforcement Learning
Wang, Haixin
Cui, Hejie
Zhang, Chenwei
Liu, Xin
Jin, Shuowei
Geng, Shijie
Zhang, Xinyang
Zalmout, Nasser
Shi, Zhenyu
Sun, Yizhou
Artificial Intelligence
Recent progress in multi-turn reinforcement learning (RL) has significantly improved reasoning LLMs' performances on complex interactive tasks. Despite advances in stabilization techniques such as fine-grained credit assignment and trajectory filtering, instability remains pervasive and often leads to training collapse. We argue that this instability stems from inefficient exploration in multi-turn settings, where policies continue to generate low-information actions that neither reduce uncertainty nor advance task progress. To address this issue, we propose Token- and Turn-level Policy Optimization (T$^2$PO), an uncertainty-aware framework that explicitly controls exploration at fine-grained levels. At the token level, T$^2$PO monitors uncertainty dynamics and triggers a thinking intervention once the marginal uncertainty change falls below a threshold. At the turn level, T$^2$PO identifies interactions with negligible exploration progress and dynamically resamples such turns to avoid wasted rollouts. We evaluate T$^2$PO in diverse environments, including WebShop, ALFWorld, and Search QA, demonstrating substantial gains in training stability and performance improvements with better exploration efficiency. Code is available at: https://github.com/WillDreamer/T2PO.
title T$^2$PO: Uncertainty-Guided Exploration Control for Stable Multi-Turn Agentic Reinforcement Learning
topic Artificial Intelligence
url https://arxiv.org/abs/2605.02178