- on: Oct. 20, 2026
- in: Article
Reactive Optimizers
@misc{bai2026reactive,
title = { Reactive Optimizers },
author = { Bai, Xingjian and
Liang, Jia-Hao and
Teoh, Jayden and
Sitzmann, Vincent },
year = { 2026 },
booktitle = { Article },
} We put an LLM agent at the heart of the optimizer. It watches the training dynamics, reacts to them, and rewrites the optimizer’s source code as training goes, all within a single run. When no recipe has been tuned for a task, our system OPAL (OPtimizer with an Agent in the Loop) matches or beats the best off-the-shelf recipe across image and language tasks. The agent spontaneously discovers sophisticated schedules, such as learning-rate increases and per-module rate changes, and intricate strategies to prevent loss spikes and escape overfitting.