I'm a first-year Computer Science PhD student at Harvard. My research focuses on developing robust and scalable tools for AI post-training. I am very fortunate to be advised by Prof. Flavio du Pin Calmon.

Publications

Recent Research

Always happy to chat about research or potential collaborations! Check out my recent work below.

ICML 2nd Workshop on Models of Human Feedback for AI Alignment 2025

Inference-Time Reward Hacking in Large Language Models

Hadi Khalaf, Claudio Mayrink Verdun, Alex Oesterling, Himabindu Lakkaraju, Flavio du Pin Calmon

TL;DR: We characterize reward hacking in inference-time alignment methods like Best-of-n, introduce an efficient approximation of the optimal RLHF solution, and propose a hedging strategy to mitigate hacking.

ACM Conference on Fairness, Accountability, and Transparency (FAccT) 2025

🏆 Best Paper Award at the New England NLP Workshop

AI Alignment at Your Discretion

Maarten Buyl, Hadi Khalaf, Claudio Mayrink Verdun, Lucas Monteiro Paes, Caio C. Vieira Machado, Flavio du Pin Calmon

TL;DR: We risk deploying unsafe AI systems if we ignore their discretion in applying alignment objectives.

Education

2024—Present

Harvard University

Ph.D. in Computer Science

Advisor: Prof. Flavio Calmon

2020—2024

American University of Beirut

B.S. in Statistics and B.E. in Computer Engineering

Experience

Summer 2023

Research Intern — Economics Department at Harvard

Advisor: Prof. Elie Tamer

Developed tools for counterfactual estimation in binary games.