Linxin Song

Linxin Song (宋林鑫) is a third-year Computer Science Ph.D. student at the University of Southern California, co-advised by Prof. Jieyu Zhao and Prof. Yue Wang. Before that, he was a M.Eng student at the Graduate School of Creative Science and Engineering, Waseda University (早稲田大学) in Tokyo, supervised by Prof. Masayuki Goto. He also collaborates closely with Jieyu Zhang, whose work centers on interactive and data-centric AI/ML.

• Fields: NLP, Agentic AI, Synthetic Data, Post Training
• Websites: Google Scholar, X, GitHub
• Contact: rm[dot]social[dot]song1[at]gmail[dot]com

Recent publication: ExeVRM — Video-Based Reward Modeling for Computer-Use Agent

I work on multimodal language models and the digital agentic systems they power, spanning data curation, post-training methods, and end-to-end agent design. My current focus is building robust, efficient computer-use and coding agents. I’m also deeply interested in embodied AI, and I’m looking for opportunities to transfer paradigms between physical agents and digital agents.

(* denotes equal contribution)

Robotics

• NEW! Reflex: Visually Grounded Reactive Humanoid Control
  Taoyang Jia*, Weikai Huang*, Linxin Song*, Jared Darlington, Jieyu Zhao, Yue Wang, Jiafei Duan, Zhongzheng Ren, Ranjay Krishna

Post Training

• Video-Based Reward Modeling for Computer-Use Agent
  Linxin Song, Jieyu Zhang, Huanxin Sheng, Taiwei Shi, Gupta Rahul, Yang Liu, Ranjay Krishna, Jian Kang, Jieyu Zhao
  ECCV 2026
• Experiential Reinforcement Learning
  Taiwei Shi, Sihao Chen, Bowen Jiang, Linxin Song, Longqi Yang, Jieyu Zhao
  Preprint
• The Hallucination Tax of Reinforcement Finetuning
  Linxin Song*, Taiwei Shi*, Jieyu Zhao
  EMNLP 2025 (findings)
  Covered by: MarkTechPost
• Efficient Reinforcement Finetuning via Adaptive Curriculum Learning
  Taiwei Shi, Yiyang Wu, Linxin Song, Tianyi Zhou, Jieyu Zhao
  TMLR

Agentic AI

• CoAct-1: Computer-using Multi-Agent System with Coding Actions
  Linxin Song, Yutong Dai, Viraj Prabhu, Jieyu Zhang, Taiwei Shi, Li Li, Junnan Li, Silvio Savarese, Zeyuan Chen, Jieyu Zhao, Ran Xu, Caiming Xiong
  ICLR 2026.
  Covered by: MarkTechPost | VentureBeat

• Adaptive In-conversation Team Building for Language Model Agents
  Linxin Song*, Jiale Liu*, Jieyu Zhang, Shaokun Zhang, Ao Luo, Shijian Wang, Qingyun Wu, Chi Wang
  AIA @COLM 2025.

Language Model and Agent Evaluation

• NEW! Converted, Not Equivalent: Benchmarking Codebase Conversion via Observational Equivalence
  Linxin Song, Jiefeng Chen, Yue Huang, Bhavana Dalvi Mishra, Chi Wang, Jieyu Zhao, Jinsung Yoon, Tomas Pfister
  Preprint
• NEW! The Blind Spot of Agent Safety: How Benign User Instructions Expose Critical Vulnerabilities in Computer-Use Agents
  Xuwei Ding*, Skylar Zhai*, Linxin Song*, Jiate Li, Taiwei Shi, Nicholas Meade, Siva Reddy, Jian Kang, Jieyu Zhao
  Preprint
• Discovering Knowledge Deficiencies of Language Models on Massive Knowledge Base
  Linxin Song, Xuwei Ding, Jieyu Zhang, Taiwei Shi, Ryotaro Shimizu, Rahul Gupta, Yang Liu, Jian Kang, Jieyu Zhao
  COLM 2025
• Explaining Length Bias in LLM-Based Preference Evaluations
  Zhengyu Hu, Linxin Song, Jieyu Zhang, Zheyuan Xiao, Jingang Wang, Zhenyu Chen, Hui Xiong
  EMNLP 2025 (findings)

• (TA) DSCI-250: Introduction to Data Science, 2024 Fall
• (TA) DSCI-566: Deep Learning and its Applications, 2025 Spring

• Microsoft Research
  2026.06 - 2026.08
  Mentor: Baolin Peng and Jianfeng Gao
• Google
  2026.02-2026.05
  Mentor: Jiefeng Chen and Jinsung Yoon
• Salesforce Research - Research Intern
  2025.05-2026.01
  Mentor: Yutong Dai, Zeyuan Chen, and Ran Xu

• Maintainer of AG2 (Autogen), an open-source framework for building and coordinating systems of AI agents.
• Reviewer (for multiple years): WACV, KDD, NeurIPS, DMLR, ICLR, AISTATS, ACL, EMNLP, etc