Xijie Gong

Xijie Gong

龚熙杰
Undergraduate, Software Engineering, UESTC · Expected 2028
GPA: 4.0/4.0 · Rank: 2/89

About Me

I am a third-year undergraduate in Software Engineering at the University of Electronic Science and Technology of China (UESTC), expected to graduate in 2028.

My research focuses on foundation models and the science of large language models. I am especially interested in why model capabilities emerge and how learned representations and internal computations give rise to them. My current work examines these questions in knowledge representation, reasoning, and agentic decision-making. My long-term goal is to uncover principles that can guide the design and training of foundation models.

Research interests: Foundation Models · Science of Large Language Models · Interpretability

Recent News

2026.09 Our paper on agentic tool calling was accepted to NeurIPS 2026 as a Main Track Poster.
2026.08 Preprint "Verbalizing Multi-Token Concepts in LLMs" is available on arXiv.
2026.07 I joined the Delta-I Lab, College of AI (CAI), Tsinghua University, as a research intern.
2025.12 Received the National Scholarship (Top 1%).
2025.10 Won 3rd Place in the RoboSense 2025 Challenge, Track 1.

Publication and Competitions

NeurIPS 2026 Main Track Poster

How Do Agentic LLMs Decide to Call Tools? A Scaffold Default Controlled by Suppression

Xijie Gong, Tingxu Han, Jiahao Zhang, Wei Song, Ziqi Ding, Hanqi Yan, Youcheng Sun, Lijie Hu

Tool calling is central to agentic LLMs, yet its internal decision mechanism remains poorly understood. Using minimally contrastive prompts, we identify a localized tool-call vector with causal sufficiency and necessity. We find that the agent scaffold induces a strong prior to call tools, while analysis-oriented requests suppress this prior.

@inproceedings{gong2026agentic, title = {How Do Agentic LLMs Decide to Call Tools? A Scaffold Default Controlled by Suppression}, author = {Gong, Xijie and Han, Tingxu and Zhang, Jiahao and Song, Wei and Ding, Ziqi and Yan, Hanqi and Sun, Youcheng and Hu, Lijie}, booktitle = {Advances in Neural Information Processing Systems (NeurIPS)}, year = {2026} }
Preprint arXiv 2026

Verbalizing Multi-Token Concepts in LLMs

Xijie Gong, Zimeng Huang, Tonghan Wang

Concept Lens extends token-level lens methods to multi-token concepts by using token clues to propose candidate concepts and scoring their representations against the source activation. Across 2,400 multi-hop cloze prompts and five LLMs (8B–70B), it enables multi-token readout and supports causal concept-swap interventions.

@article{gong2026verbalizing, title = {Verbalizing Multi-Token Concepts in LLMs}, author = {Gong, Xijie and Huang, Zimeng and Wang, Tonghan}, journal = {arXiv preprint arXiv:2608.31084}, year = {2026} }
RoboSense Challenge · IROS 2025 Track 1: Driving with Language — 3rd Place

The RoboSense Challenge: Sense Anything, Navigate Anywhere, Adapt Across Platforms

The RoboSense 2025 Challenge unifies five complementary tracks spanning language-grounded decision making, socially compliant navigation, sensor configuration generalization, cross-view and cross-modal correspondence, and cross-platform 3D perception. This report provides standardized datasets, baselines, and unified evaluation protocols for robust robot sensing under domain shifts, and consolidates insights from 23 winning solutions.

Research Experience

2026.07 – Present
Tsinghua University · College of AI (CAI) · Delta-I Lab
Research Intern, Foundation Models
Research on foundation models and the science of large language models.
2025.12 – 2026.05
Mohamed bin Zayed University of Artificial Intelligence (MBZUAI) · Department of Machine Learning
Research Intern, LLM Interpretability
Research on mechanistic interpretability of large language models.
2025.06 – 2025.11
Shanghai Jiao Tong University (SJTU) · SAI AutoLab
Research Intern, Autonomous Driving
Research on autonomous driving perception.

Education

2024.09 – Present
University of Electronic Science and Technology of China (UESTC)
B.Eng. in Software Engineering (Expected 2028)
GPA: 4.0/4.0 · Rank: 2/89

Honors & Awards

Chinese Collegiate Computing Competition (4C), National Second Prize 2026.08
National Scholarship (Top 1%) 2025.12
First-Class Scholarship, UESTC 2025.10