Yikun Fu
Author directory2026
One Policy, Any Budget: Internalizing Budget-Aware Search via Reinforcement Learning
Xiaowei Sun | Jin Li | Yili Hong | Yikun Fu | Yanghua Xiao
Findings of the Association for Computational Linguistics: EMNLP 2026
Xiaowei Sun | Jin Li | Yili Hong | Yikun Fu | Yanghua Xiao
Findings of the Association for Computational Linguistics: EMNLP 2026
While reinforcement learning has enabled LLM-based search agents to invoke external tools, existing methods train under fixed budgets and cannot adapt when constraints vary at deployment. We propose AnySearch, a framework that enables a single policy to perform budget-aware search under any budget constraint through a training scaffold and curriculum reinforcement learning. In the first phase, we train the agent with explicit budget state injection and structured reasoning prompts that guide efficient allocation under linearly decaying budgets. In the second phase, the scaffold is removed and the agent learns to operate autonomously under adaptively sampled budget constraints, matching inference conditions. Both phases are optimized with a composite reward that couples answer accuracy with budget efficiency through absolute and relative signals, where an adaptive weight amplifies the efficiency signal for high-accuracy queries and attenuates it for low-accuracy ones. Extensive experiments on seven general and multi-hop QA benchmarks show that our method outperforms baselines across all budget scales, generalizes to unseen constraints beyond the training range, and achieves superior tool productivity without excessive token overhead.
MacAgentBench: Benchmarking AI Agents on Real-World macOS Desktop
Yikun Fu | Bowen Fu | Zhenyu Wu | Shuang Cheng | Xiaowei Sun | Bowen Yang | Zehao Li | Yibo Zhao | Zichen Ding | Zhoumianze Liu | Shijie Wang | Biqing Qi | Bowen Zhou
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Yikun Fu | Bowen Fu | Zhenyu Wu | Shuang Cheng | Xiaowei Sun | Bowen Yang | Zehao Li | Yibo Zhao | Zichen Ding | Zhoumianze Liu | Shijie Wang | Biqing Qi | Bowen Zhou
Proceedings of the 2026 Conference on Empirical Methods in Natural Language Processing
Computer use agents (CUAs) have advanced rapidly in desktop automation, and a growing number of users deploy CUAs such as OpenClaw on Mac Mini for always-on automation. However, existing benchmarks, including those for macOS, evaluate agents without framework augmentation and rely on binary evaluation. As a result, they fail to capture both the framework capabilities leveraged by modern CUAs and the partial progress on long-horizon, multi-application tasks. We present MacAgentBench, a comprehensive macOS agent benchmark comprising 169 seed tasks expanded into 676 task instances across 25 applications, with nearly 60% involving both GUI and CLI interaction. The benchmark adopts deterministic rule-based evaluation and introduces fine-grained multi-checkpoint scoring with capability annotations for multi-application tasks. Experiments across three frameworks and 16 models show that the best configuration, Claude Opus 4.6 on OpenClaw, attains 73.7% Pass@1, while this advantage is primarily driven by the skill library rather than by framework design. Fine-grained metrics further reveal that models with similar Pass@1 can differ substantially in sub-goal completion.
MARS2: Scaling Multi-Agent Tree Search via Reinforcement Learning for Code Generation
Pengfei Li | Shijie Wang | Fangyuan Li | Yikun Fu | Kaifeng Liu | Kaiyan Zhang | Dazhi Zhang | Yuqiang Li | Biqing Qi | Bowen Zhou
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Pengfei Li | Shijie Wang | Fangyuan Li | Yikun Fu | Kaifeng Liu | Kaiyan Zhang | Dazhi Zhang | Yuqiang Li | Biqing Qi | Bowen Zhou
Proceedings of the 64th Annual Meeting of the Association for Computational Linguistics (Volume 1: Long Papers)
Reinforcement learning (RL) paradigms have demonstrated strong performance on reasoning-intensive tasks such as code generation. However, limited trajectory diversity often leads to diminishing returns, which constrains the achievable performance ceiling. Search-enhanced RL alleviates this issue by introducing structured exploration, which remains constrained by the single-agent policy priors. Meanwhile, leveraging multiple interacting policies can acquire more diverse exploratory signals, but existing approaches are typically decoupled from structured search. We propose MARS2 (Multi-Agent Reinforced Tree-Search Scaling), a unified RL framework in which multiple independently-optimized agents collaborate within a shared tree-structured search environment. MARS2 models the search tree as a learnable multi-agent interaction environment, enabling heterogeneous agents to collaboratively generate and refine candidate solutions within a shared search topology. To support effective learning, we introduce a path-level group advantage formulation based on tree-consistent reward shaping, which facilitates effective credit assignment across complex search trajectories. Experiments on code generation benchmarks show that MARS2 consistently improves performance across diverse model combinations and training settings, demonstrating the effectiveness of coupling multi-agent collaboration with tree search for enhancing reinforcement learning. Our code is publicly available at https://github.com/TsinghuaC3I/MARTI.
2025
AgentCPM-GUI: Building Mobile-Use Agents with Reinforcement Fine-Tuning
Zhong Zhang | Yaxi Lu | Yikun Fu | Yupeng Huo | Shenzhi Yang | Yesai Wu | Han Si | Xin Cong | Haotian Chen | Yankai Lin | Jie Xie | Wei Zhou | Wang Xu | Yuanheng Zhang | Zhou Su | Zhongwu Zhai | Xiaoming Liu | Yudong Mei | Jianming Xu | Hongyan Tian | Chongyi Wang | Chi Chen | Yuan Yao | Zhiyuan Liu | Maosong Sun
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
Zhong Zhang | Yaxi Lu | Yikun Fu | Yupeng Huo | Shenzhi Yang | Yesai Wu | Han Si | Xin Cong | Haotian Chen | Yankai Lin | Jie Xie | Wei Zhou | Wang Xu | Yuanheng Zhang | Zhou Su | Zhongwu Zhai | Xiaoming Liu | Yudong Mei | Jianming Xu | Hongyan Tian | Chongyi Wang | Chi Chen | Yuan Yao | Zhiyuan Liu | Maosong Sun
Proceedings of the 2025 Conference on Empirical Methods in Natural Language Processing: System Demonstrations
Large language model agents have enabled GUI-based automation, particularly for mobile devices. However, deployment remains limited by noisy data, poor generalization, and lack of support for non-English GUIs. In this work, we present AgentCPM-GUI, an 8B-parameter GUI agent built for robust and efficient on-device GUI interaction. Our training pipeline includes grounding-aware pre-training to enhance perception, supervised fine-tuning on high-quality Chinese and English trajectories to imitate human-like actions, and reinforcement fine-tuning with GRPO to improve reasoning capability. AgentCPM-GUI achieves promising performance on five public benchmarks and our proposed Chinese benchmark CAGUI. To facilitate reproducibility and further research, we publicly release all code, model checkpoint, and evaluation data at: https://github.com/OpenBMB/AgentCPM-GUI
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Co-authors
- Biqing Qi 2
- Xiaowei Sun 2
- Shijie Wang 2
- Bowen Zhou 2
- Chi Chen 1
- Haotian Chen 1
- Shuang Cheng 1
- Xin Cong 1
- Zichen Ding 1
- Bowen Fu 1
- Yili Hong 1
- Yupeng Huo 1
- Fangyuan Li 1
- Jin Li 1
- Pengfei Li 1
- Yuqiang Li 1
- Zehao Li 1
- Yankai Lin (林衍凯) 1
- Kaifeng Liu 1
- Xiaoming Liu 1
- Zhiyuan Liu 1
- Zhoumianze Liu 1
- Yaxi Lu 1
- Yudong Mei 1
- Han Si (司函) 1
- Zhou Su 1
- Maosong Sun (孙茂松) 1
- Hongyan Tian 1
- Chongyi Wang 1
- Yesai Wu 1
- Zhenyu Wu 1
- Yanghua Xiao 1
- Jie Xie 1
- Jianming Xu 1
- Wang Xu 1
- Bowen Yang 1
- Shenzhi Yang 1
- Yuan Yao 1
- Zhongwu Zhai 1
- Dazhi Zhang 1
- Kaiyan Zhang 1
- Yuanheng Zhang 1
- Zhong Zhang 1
- Yibo Zhao 1
- Wei Zhou 1