arXiv Machine Learning

Cyclical Entropy Eruption: Entropy Dynamics in Agent Reinforcement Learning

The paper introduces the phenomenon of cyclical entropy eruption in agent reinforcement learning, where entropy rises sharply and then subsides in recurring cycles, unlike the steady low entropy seen in single‑turn reasoning RL. It breaks this dynamic into three phases, offering theoretical and empirical insights into the mechanisms driving the oscillation. The authors propose SEAL, a lightweight auxiliary loss that separates correct and incorrect trajectories in representation space, which stabilizes training and improves downstream agent performance across various benchmarks and algorithms.

arXiv AI
Oct 31

AEM: Adaptive Entropy Modulation for Multi-Turn Agentic Reinforcement Learning

AEM: Adaptive Entropy Modulation for Multi‑Turn Agentic Reinforcement Learning proposes a supervision‑free credit assignment technique that adjusts entropy dynamics at the response level during RL training. By aligning uncertainty estimation with the granularity of LLM agent actions and rescaling advantages based on a response‑level uncertainty proxy, AEM improves the exploration‑exploitation balance without relying on dense intermediate supervision. Experiments on ALFWorld, WebShop, and SWE‑bench‑Verified show consistent performance gains across models from 1.5B to 32B, including a 1.4% improvement in a state‑of‑the‑art software‑engineering RL framework.

By Haotian Zhao, Songlin Zhou, Yuxin Zhang, Stephen S. -T. Yau, Wenyu Zhang, Lun Tian, Tianshu Zhu, Yifeng Huang, Yucheng Zeng, Jingnan Gu, Daxiang Dong, Jianmin Wu
arXiv AI
Sep 2

Skill Reuse as Compression in Agentic RL

The paper introduces ReuseRL, a method that applies the Minimum Description Length principle to agentic reinforcement learning. By extracting a shared skill dictionary from successful trajectories and adding a segmentation cost to the RL objective, ReuseRL discourages idiosyncratic behaviors and promotes reusable abstract patterns. Experiments on ALFWorld, TextWorld-Cooking, and Countdown-Stepwise show that ReuseRL improves both in‑distribution and out‑of‑distribution success compared to vanilla GRPO and other baselines.

By Zhikun Xu, Yu Feng, Jacob Dineen, Taiwei Shi, Jieyu Zhao, Ben Zhou
arXiv AI
Jul 28

From Proprietary to Open-Source: Bridging the Distribution Gap via Multi-Agent Protocol Distillation in Agentic Search

arXiv:2607. 24280v1 Announce Type: new Abstract: Agentic search enables large language models to solve knowledge-intensive tasks by interleaving multi-step reasoning with retrieval, yet optimizing this with outcome-based reinforcement learning (RL) provides only sparse supervision.

By Junlin Liu, Jiangwang Chen, Zixin Song, Shuaiyu Zhou, Chunji Lv, Hank Wu, Kailin Jiang, Jinyang Wu, Bohan Yu, Chenxi Zhou
arXiv Machine Learning
Aug 27

Demystifying Reinforcement Learning Post-Training of Language Models

The paper "Demystifying Reinforcement Learning Post-Training of Language Models" investigates how reinforcement learning (RL) post‑training enhances large language models (LLMs) for tasks such as reasoning, math, and coding. By isolating RL components in a controlled setting, the authors analyze how the base model’s prior distribution, reward granularity, prompt diversity, and model scale influence outcomes, using policy entropy to compare pre‑training, supervised fine‑tuning (SFT), and RL stages. The study clarifies the role of spurious rewards, the importance of the base model’s probability mass on desired behaviors, and how these factors interact to determine post‑training success, offering a practical primer for NLP researchers. "whyItMatters":"The work provides a clearer understanding of RL post‑training mechanics, helping researchers and practitioners effectively apply RL to improve LLM capabilities."

By Donovan Clay, Saket Gollapudi, Sankar Harilal, Min Jang, Jacob Morrison, Sewoong Oh, Natasha Jaques
arXiv AI
Oct 12

Rollout-Time Intervention: Unlocking Agentic Reinforcement Learning Beyond Policy Limits

The paper introduces Rollout-Time Intervention (RTI), a method that uses reward-side evidence during rollouts to transform unsuccessful trajectories into successful ones, thereby providing learning signals for tasks beyond a policy’s intrinsic exploration limits. RTI filters out trajectories with excessive distributional shifts, allowing these off-policy interventions to guide policy optimization effectively. Experiments on five benchmarks show that RTI consistently outperforms existing RL baselines, enabling post-trained policies to approach the performance of stronger large language models and surpass their original capability boundaries.

By Chen Xi, Ding Ruixue, Wang Zhigaoyuan, Zhang Fanrui, Zhang Qiang, Chen Boli, Wang Shihang, Wang Tianfu, Ren Ailin, Wang Pengyong, Xie Pengjun, Xiong Hui
arXiv AI
Oct 19

Agentic In-Context Learning: What Algorithms Can Transformers Learn in Closed-Loop Interaction?

The paper introduces Agentic In-Context Learning (Agentic ICL), a framework where fixed‑parameter Transformers learn from interactions that shape the context they receive. It models an interactive learner with state, update, and decision rules, covering active learning, bandits, and online reinforcement learning, and demonstrates that causal Transformers can approximate these algorithms over a finite horizon. Experiments show that Transformers can learn to execute recursions and that different reward signals produce distinct decision policies, with alignment between process supervision and outcome‑optimal actions influencing learned behavior.

By Shiguang Wu, Yaqing Wang, Quanming Yao
arXiv AI
Jun 4

Policy Split: Incentivizing Dual-Mode Exploration in LLM Reinforcement with Dual-Mode Entropy Regularization

arXiv:2604. 11510v2 Announce Type: replace-cross Abstract: To encourage diverse exploration in reinforcement learning (RL) for large language models (LLMs) without compromising accuracy, we propose Policy Split, a novel paradigm that bifurcates the policy into normal and high-entropy modes with a high-entropy prompt.

By Jiashu Yao, Heyan Huang, Daiqing Wu, Zeming Liu, Yuhang Guo
Hugging Face Trending Papers
Sep 28

Shockingly Simple Self-retrospection Improves Agentic Models Without RL

The paper explores Retrospection-Only Fine-Tuning (ROFT), a method where a language-model agent improves its behavior by generating and training on explanations of its own experiences, without external teachers or reward signals. In software‑engineering tasks with Qwen3.5‑4B, ROFT achieves comparable or better solve rates than GRPO while requiring fewer updates and training time, and can learn from failures alone. Behavioral analysis shows ROFT indirectly assigns credit to actions and can produce shorter, more direct solutions when prompted to focus on direct solutions.