Youtu-LLM: Unlocking the Native Agentic Potential for Lightweight Large Language Models

Fuente: arXiv
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Main Authors: Lu, Junru, Qin, Jiarui, Qiao, Lingfeng, Li, Yinghui, Dai, Xinyi, Ke, Bo, He, Jianfeng, Qiao, Ruizhi, Yin, Di, Sun, Xing, Wu, Yunsheng, Liu, Yinsong, Liu, Shuangyin, Tang, Mingkong, Lin, Haodong, Kuang, Jiayi, Meng, Fanxu, Tang, Xiaojuan, Xi, Yunjia, Huang, Junjie, Yang, Haotong, Shen, Zhenyi, Li, Yangning, Zhang, Qianwen, Yu, Yifei, An, Siyu, Dong, Junnan, Wang, Qiufeng, Wang, Jie, Chen, Keyu, Wen, Wei, Guo, Taian, Shen, Zhifeng, Yu, Daohai, Li, Jiahao, Li, Ke, Li, Zongyi, Tan, Xiaoyu
Format: Preprint
Published: 2025
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author Lu, Junru
Qin, Jiarui
Qiao, Lingfeng
Li, Yinghui
Dai, Xinyi
Ke, Bo
He, Jianfeng
Qiao, Ruizhi
Yin, Di
Sun, Xing
Wu, Yunsheng
Liu, Yinsong
Liu, Shuangyin
Tang, Mingkong
Lin, Haodong
Kuang, Jiayi
Meng, Fanxu
Tang, Xiaojuan
Xi, Yunjia
Huang, Junjie
Yang, Haotong
Shen, Zhenyi
Li, Yangning
Zhang, Qianwen
Yu, Yifei
An, Siyu
Dong, Junnan
Wang, Qiufeng
Wang, Jie
Chen, Keyu
Wen, Wei
Guo, Taian
Shen, Zhifeng
Yu, Daohai
Li, Jiahao
Li, Ke
Li, Zongyi
Tan, Xiaoyu
author_facet Lu, Junru
Qin, Jiarui
Qiao, Lingfeng
Li, Yinghui
Dai, Xinyi
Ke, Bo
He, Jianfeng
Qiao, Ruizhi
Yin, Di
Sun, Xing
Wu, Yunsheng
Liu, Yinsong
Liu, Shuangyin
Tang, Mingkong
Lin, Haodong
Kuang, Jiayi
Meng, Fanxu
Tang, Xiaojuan
Xi, Yunjia
Huang, Junjie
Yang, Haotong
Shen, Zhenyi
Li, Yangning
Zhang, Qianwen
Yu, Yifei
An, Siyu
Dong, Junnan
Wang, Qiufeng
Wang, Jie
Chen, Keyu
Wen, Wei
Guo, Taian
Shen, Zhifeng
Yu, Daohai
Li, Jiahao
Li, Ke
Li, Zongyi
Tan, Xiaoyu
contents We introduce Youtu-LLM, a lightweight yet powerful language model that harmonizes high computational efficiency with native agentic intelligence. Unlike typical small models that rely on distillation, Youtu-LLM (1.96B) is pre-trained from scratch to systematically cultivate reasoning and planning capabilities. The key technical advancements are as follows: (1) Compact Architecture with Long-Context Support: Built on a dense Multi-Latent Attention (MLA) architecture with a novel STEM-oriented vocabulary, Youtu-LLM supports a 128k context window. This design enables robust long-context reasoning and state tracking within a minimal memory footprint, making it ideal for long-horizon agent and reasoning tasks. (2) Principled "Commonsense-STEM-Agent" Curriculum: We curated a massive corpus of approximately 11T tokens and implemented a multi-stage training strategy. By progressively shifting the pre-training data distribution from general commonsense to complex STEM and agentic tasks, we ensure the model acquires deep cognitive abilities rather than superficial alignment. (3) Scalable Agentic Mid-training: Specifically for the agentic mid-training, we employ diverse data construction schemes to synthesize rich and varied trajectories across math, coding, and tool-use domains. This high-quality data enables the model to internalize planning and reflection behaviors effectively. Extensive evaluations show that Youtu-LLM sets a new state-of-the-art for sub-2B LLMs. On general benchmarks, it achieves competitive performance against larger models, while on agent-specific tasks, it significantly surpasses existing SOTA baselines, demonstrating that lightweight models can possess strong intrinsic agentic capabilities.
format Preprint
id arxiv_https___arxiv_org_abs_2512_24618
institution arXiv
publishDate 2025
record_format arxiv
spellingShingle Youtu-LLM: Unlocking the Native Agentic Potential for Lightweight Large Language Models
Lu, Junru
Qin, Jiarui
Qiao, Lingfeng
Li, Yinghui
Dai, Xinyi
Ke, Bo
He, Jianfeng
Qiao, Ruizhi
Yin, Di
Sun, Xing
Wu, Yunsheng
Liu, Yinsong
Liu, Shuangyin
Tang, Mingkong
Lin, Haodong
Kuang, Jiayi
Meng, Fanxu
Tang, Xiaojuan
Xi, Yunjia
Huang, Junjie
Yang, Haotong
Shen, Zhenyi
Li, Yangning
Zhang, Qianwen
Yu, Yifei
An, Siyu
Dong, Junnan
Wang, Qiufeng
Wang, Jie
Chen, Keyu
Wen, Wei
Guo, Taian
Shen, Zhifeng
Yu, Daohai
Li, Jiahao
Li, Ke
Li, Zongyi
Tan, Xiaoyu
Computation and Language
We introduce Youtu-LLM, a lightweight yet powerful language model that harmonizes high computational efficiency with native agentic intelligence. Unlike typical small models that rely on distillation, Youtu-LLM (1.96B) is pre-trained from scratch to systematically cultivate reasoning and planning capabilities. The key technical advancements are as follows: (1) Compact Architecture with Long-Context Support: Built on a dense Multi-Latent Attention (MLA) architecture with a novel STEM-oriented vocabulary, Youtu-LLM supports a 128k context window. This design enables robust long-context reasoning and state tracking within a minimal memory footprint, making it ideal for long-horizon agent and reasoning tasks. (2) Principled "Commonsense-STEM-Agent" Curriculum: We curated a massive corpus of approximately 11T tokens and implemented a multi-stage training strategy. By progressively shifting the pre-training data distribution from general commonsense to complex STEM and agentic tasks, we ensure the model acquires deep cognitive abilities rather than superficial alignment. (3) Scalable Agentic Mid-training: Specifically for the agentic mid-training, we employ diverse data construction schemes to synthesize rich and varied trajectories across math, coding, and tool-use domains. This high-quality data enables the model to internalize planning and reflection behaviors effectively. Extensive evaluations show that Youtu-LLM sets a new state-of-the-art for sub-2B LLMs. On general benchmarks, it achieves competitive performance against larger models, while on agent-specific tasks, it significantly surpasses existing SOTA baselines, demonstrating that lightweight models can possess strong intrinsic agentic capabilities.
title Youtu-LLM: Unlocking the Native Agentic Potential for Lightweight Large Language Models
topic Computation and Language
url https://arxiv.org/abs/2512.24618