Intern-S2-Preview: Scientific Agentic Foundation Model
Authors: name: Lei Bai, name: Jiaqi Cao, name: Chiyu Chen, name: Guanzhou Chen, name: Kai Chen, name: Guangran Cheng, name: Erfei Cui, name: Xuanlang Dai, name: Shengyuan Ding, name: Shangheng Du, name: Yanhui Duan, name: Yue Fan, name: Youqing Fang, name: Quan Gan, name: Yuanyuan Gao, name: Jiaye Ge, name: Lixin Gu, name: Yuzhe Gu, name: Qipeng Guo, name: Junjun He, name: Xin Hong, name: Ming Hu, name: Zhouqi Hua, name: Haian Huang, name: Junhao Huang, name: Zixian Huang, name: Minxi Jin, name: Lingkai Kong, name: Alexander Lam, name: Zehao Li, name: Zonglin Li, name: Tianhao Liang, name: Dahua Lin, name: Junyao Lin, name: Tianyang Lin, name: Zhouhan Lin, name: Jiangning Liu, name: Jin Liu, name: Kuikun Liu, name: Wenran Liu, name: Yifei Liu, name: Yuhong Liu, name: Yuhong Liu, name: Zhoumianze Liu, name: Ziyan Liu, name: Ziyu Liu, name: Haijun Lv, name: Han Lv, name: Chengqi Lyu, name: Le Ma, name: Ningsheng Ma, name: Zerun Ma, name: Haoyang Peng, name: Runyu Peng, name: Jifei Shan, name: Zixin Shang, name: Kou Shi, name: Xiang Shi, name: Qisheng Su, name: Xuerui Su, name: Hao Sun, name: Xiao Sun, name: Yanan Sun, name: Yu Sun, name: Huanze Tang, name: Yinghao Tang, name: Wenhui Tian, name: Zhongbo Tian, name: Bingli Wang, name: Haomin Wang, name: Jiarui Wang, name: Jingzhi Wang, name: Rui Wang, name: Xiquan Wang, name: Yi Wang, name: Zhecan Wang, name: Ziyi Wang, name: Zun Wang, name: Rubin Wei, name: Lianyi Wu, name: Wen Wu, name: Yue Wu, name: Yuhan Wu, name: Zhenyu Wu, name: Zijian Wu, name: Shuhao Xing, name: Jun Xu, name: Xingle Xu, name: Xuenan Xu, name: Xiangchao Yan, name: Ziang Yan, name: Bowen Yang, name: Danni Yang, name: Lin Yang, name: Zhiqi Yang, name: Qian Yao, name: Haochen Ye, name: Peng Ye, name: Jinhui Yin, name: Jiashuo Yu, name: Dingbo Yuan, name: Fei Yuan, name: Yuhang Zang, name: Bo Zhang, name: Chao Zhang, name: Chen Zhang, name: Hongjie Zhang, name: Junming Zhang, name: Wenlong Zhang, name: Wenwei Zhang, name: Yiming Zhang, name: Zhuo Zhang, name: Ziyang Zhang, name: Haiteng Zhao, name: Penghao Zhao, name: Yibo Zhao, name: Zhonghan Zhao, name: Zhihang Zhong, name: Bowen Zhou, name: Peiheng Zhou, name: Xin Zhou, name: Xinyu Zhou, name: Yunhua Zhou, name: Dongsheng Zhu, name: Yicheng Zou
Organization: Intern Large Models

Scientific discovery increasingly requires AI systems that can reason over scientific evidence of heterogeneous modalities, interact with scientific tools and environments, and sustain progress across long task horizons. We present Intern-S2-Preview, a series of scientific agentic foundation models designed to support multimodal scientific understanding, reasoning, generation, and long-horizon tasks. The training pipeline begins with scientific multimodal pre-training over rendered scientific documents, interleaved image-text data, and diverse scientific corpora. Starting from the pretrained checkpoint, we apply a unified post-training pipeline consisting of supervised fine-tuning, scalable multi-task reinforcement learning (RL), black- and white-box agentic RL, and on-policy distillation. This pipeline is supported by practical techniques that improve rollout and training stability and efficiency, including partial rollout with off-policy correction, adaptive length regularization, online speculative decoding, robust multi-task optimization, and trace-aware experience assembly for agentic tasks. At the architecture level, Intern-S2-Preview-397B extends time series modelling from efficient long-sequence understanding to numerical forecasting, while Memory Decoder is studied as a separate memory-augmented path for rapid scientific specialization without modifying the frozen 397B backbone. Evaluations across scientific, multimodal, agentic, and general-purpose benchmarks show that Intern-S2-Preview-397B achieves competitive or leading results in multiple settings. The time series modules improve scientific signal understanding and forecasting on SciTS, while the separate Intern-MemDec-4B extension improves the Biology-Instructions average score from 56.92 to 60.32 without modifying the frozen 397B backbone.