# JAM: A Unified Action Model Framework for VLA and WAM

- Source: arXiv cs.RO
- Published: 2026-10-28T04:00:00.000Z
- RoboHot: https://robohot.news/en/items/e0doynwpsyfo7ca59yixfy4ka
- Original: https://arxiv.org/abs/2610.37219

## Summary

The authors propose the Just Action Model (JAM) framework, which breaks down the differences between VLA and WAM into three separable choices: backbone initialization, the loss objective on future observations, and whether that loss mechanism is retained at inference. JAM unifies both into a structure of a pretrained visual backbone plus an action expert, trained with an action loss and a foresight loss.