Beyond Task Success: Probing Cognitive Primitives in Web Agents
NeurIPS 2026 (In review)Xunjian Yin, Tianchen Guan, Jinao Wang, Weili Cao, Daisy Xinlei Lin, Royce Cheng-Yue, Keagan Long, Kyle Wong, Bhuwan Dhingra, Xiangjun Wang, Shuyan Zhou
Research brain. Builder hands.
Research Scientist & Engineer, Amazon AGI SF Lab
I build zero-to-one SFT/RL recipes for frontier agents: identify failure modes, turn them into targeted data and environments, design evaluations, and debug production-scale training until it learns stably. I own this process for a 100B mixture-of-experts coding agent, raising Terminal-Bench 2.0 to 45% and reaching 70% on SWE-bench Verified, outperforming leading open-weight baselines. Previously, I built and shipped Nova Act’s zero-to-one RL recipe—including algorithm experiments, environment scoping, online data curation, and fixes for reward collapse and train–inference mismatch. Nova Act launched with state-of-the-art performance on REAL Bench and WorkArena. I enjoy driving a research agenda, from choosing the right problems to carrying long-running work through to impact. Across both projects, my favorite part is finding the failure no one can quite name yet, making it measurable, and building the training system that fixes it.
My PhD at NYU was about how humans plan and learn: I ran large-scale experiments to understand what makes people get better at complex tasks, and how that compares to AI.
I think AI should be humans' thought partners, adapting to collaborate with us better and better.
For fun, I explore new interaction paradigms for human-AI collaboration: tools that adapt to how you think, not the other way around.
Built and shipped Nova Act's RL recipe from scratch. Led algorithm experiments, RL environment scoping, and public benchmark hill-climbing; designed an online data curator and fixed reward collapse and train–inference mismatch to stabilize learning at scale.
Xunjian Yin, Tianchen Guan, Jinao Wang, Weili Cao, Daisy Xinlei Lin, Royce Cheng-Yue, Keagan Long, Kyle Wong, Bhuwan Dhingra, Xiangjun Wang, Shuyan Zhou
Zhenting Qi, Jack Fan, Karly Hou, Daisy Xinlei Lin, Satyaki Chakraborty, Mete Kemertas, Yu Yao, Sophia Simeng Han, Han Zheng, Zihan Wang, Xiangjun Wang, Himabindu Lakkaraju, Yilun Du
Tianchen Guan, Daisy Xinlei Lin, Xiangjun Wang, Shuyan Zhou
Daisy Xinlei Lin, Brenden Lake, Wei Ji Ma
PaperVeronica Yeom-Song, Xinlei Lin, Ionatan Kuperwajs, Heiko Schütt, Wei Ji Ma, Luigi Acerbi
Zheyang Sam Zheng*, Xinlei Daisy Lin*, Jake Topping*, Wei Ji Ma
PaperJordan Lei, Jeroen Olieslagers, Nastaran Arfaei, Xinlei Lin, Wei Ji Ma
PaperEnida Gjoni, Ram Dyuthi Sristi, Haixin Liu, Shahar Dror, Xinlei Lin, Keelin O'Neil, Oscar M. Arroyo, Sun Woo Hong, Hannah Kim, Jeffrey Liu, Sonja Blumenstock, Byungkook Lim, Gal Mishne, Takaki Komiyama
PaperI snowboard when I can (Hokkaido is the dream), bake when I need to think, make ceramics, and am currently being managed by two cats named Boba and Milk who take their supervisory roles extremely seriously.
Currently deep in: Japanese ceramics, reward models, and the correct ratio of mascarpone to cream.