arXiv Computation and Language

Learning to Act with Task Progress: Distilling Small Agents from Compact Teacher Supervision

The paper introduces Task-Progress Distillation (TPD), an offline method that pairs each action in teacher demonstrations with a short label indicating the current task stage. A small 1.7B student model trained with 404 demonstrations using TPD achieves 72.4% mean unseen task success on ALFWorld, matching action-only supervision and outperforming a reasoning-trained student. At lower demonstration budgets, explicit stage labels significantly boost performance, raising success from 48.0% to 67.7% with 200 demos, and both approaches converge to 76.9% with 808 demos.

arXiv Machine Learning
Oct 12

State-OPD: State-Grounded On-Policy Distillation for Multi-Turn Agents

State-OPD introduces a state‑grounded on‑policy distillation framework that separates the objective task and action‑observation record from the student’s internal reasoning trajectory. By removing prior student reasoning and resampling complete reasoning‑action responses at high‑entropy states, the method improves teacher supervision and action diversity. Evaluations on ALFWorld, ScienceWorld, and WebShop show State‑OPD achieves the highest macro‑average success rates for Qwen3‑1.7B and Qwen3‑4B students, even surpassing a larger teacher model on certain tasks.

By Zhentao Zhang, Yanzhao Zheng, Yanlin Liu, Yuanqiang Yu, Tianze Xu, Chao Ma, Jihuai Zhu, Lelun Wu, Baohua Dong, Hangcheng Zhu, Ruohui Huang, Gang Yu
arXiv AI
Oct 9

Agentic Critical Training

Agentic Critical Training (ACT) is a reinforcement learning approach that trains language‑model agents to judge actions directly by pairing expert actions with alternatives and rewarding correct selection. Unlike imitation learning or self‑reflection, ACT does not require reference rationales and can be reused across model sizes. Experiments on Qwen3‑8B and Olmo‑3‑7B‑Instruct show that ACT improves performance on ALFWorld, WebShop, ScienceWorld, and outperforms supervised reflection baselines, with significant gains over IL and IL→RL baselines.

By Weize Liu, Minghui Liu, Sy-Tuyen Ho, Yongkyun Lee, Andrew Adams Schoen, Souradip Chakraborty, Xiyao Wang, Furong Huang
arXiv AI
Jun 3

What Makes Interaction Trajectories Effective for Training Terminal Agents?

arXiv:2606. 03461v1 Announce Type: new Abstract: Stronger code agents are commonly assumed to be superior teachers for post-training, yet this assumption remains poorly disentangled from task difficulty, harness design, and student capacity.

By Sidi Yang, Chaofan Tao, Jierun Chen, Tiezheng Yu, Ruoyu Wang, Yuxin Jiang, Yiming Du, Wendong Xu, Jing Xiong, Taiqiang Wu, Lifeng Shang, Xiaohui Li, Ngai Wong, Haoli Bai
arXiv AI
Oct 1

RoboCoach: World Models as Active Coaches for Compositional Robot Skills

RoboCoach introduces a world-model-guided coaching framework that uses imagined failures to direct demonstration requests and expert updates for robot manipulation tasks. The system, called RIDI, runs reusable skill experts within a shared action-conditioned world model and records the first failing subtask to decide which demonstrations to acquire and which adapters to refine. Experiments on simulation suites and real robots show that with only 150 additional subtask demonstrations, success rates increase dramatically, and the coached experts transfer effectively to unseen task compositions.

By Jiajun Liu, Yifan Chen, Yichao Liu, Jiayi Zhang, Ruoqu Chen, Shaoxuan Xie, Guocai Yao, Mengdi Xu, Sen Cui, Changshui Zhang
arXiv Machine Learning
Oct 8

TAP: Efficient Long-Horizon Agent Pruning via Trajectory-Anchored Recovery

TAP (Trajectory‑Anchored Pruning) is a structural pruning framework designed for reinforcement‑learning‑trained agents that addresses the shortcomings of existing pruning methods on long‑horizon tasks. It couples iterative channel pruning with on‑policy recovery, anchoring student interactions to teacher trajectories and re‑scoring channels using gradients from the recovery objective. Experiments show that removing 60% of FFN channels preserves 99.2% and 88.0% of task success rates on ALFWorld and WebShop while cutting GPU time per successful task by about 22% and 17%.

By Yuanzhe Li, Pengxin Wang, Yuxin Ren, Jianing Deng, Jingtong Hu, Song Wang, Jingdi Chen, Huanrui Yang
arXiv AI
Oct 5

WAM-OPD: Joint Video-Action Supervision for World Action Model Post-Training with On-Policy Distillation

WAM-OPD introduces a method for post‑training improvement of World Action Models (WAMs) by collecting student rollout histories and querying a stronger teacher for paired video and action targets. The student learns from both modalities while preserving its one‑step generation capability at deployment. Experiments on 12 RoboTwin 2.0 tasks and four real‑robot tasks show success rates rising from 33.8% to 65.7% and from 51.4% to 64.6%, respectively, with joint video‑action supervision outperforming single‑modality approaches.

By Liuhaichen Yang, Zhengyang Zhong, Hanshang Zhu, Ningwei Bai, Qichen Yin, Zhi Han, Jiarui Qin, Zhuang Jiang, Chenchao Sheng, Hanbo Ma, Junkai Liu, Junkai Sun, Dongcheng Lyu, Bo Liu, Yi Dong, Zezhi Tang