Paper Detail

VLA Foundry: A Unified Framework for Training Vision-Language-Action Models

Jean Mercat, Sedrick Keh, Kushal Arora, Isabella Huang, Paarth Shah, Haruki Nishimura, Shun Iwase, Katherine Liu

arxiv Score 6.3

Published 2026-04-21 · First seen 2026-04-22

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Abstract

We present VLA Foundry, an open-source framework that unifies LLM, VLM, and VLA training in a single codebase. Most open-source VLA efforts specialize on the action training stage, often stitching together incompatible pretraining pipelines. VLA Foundry instead provides a shared training stack with end-to-end control, from language pretraining to action-expert fine-tuning. VLA Foundry supports both from-scratch training and pretrained backbones from Hugging Face. To demonstrate the utility of our framework, we train and release two types of models: the first trained fully from scratch through our LLM-->VLM-->VLA pipeline and the second built on the pretrained Qwen3-VL backbone. We evaluate closed-loop policy performance of both models on LBM Eval, an open-data, open-source simulator. We also contribute usability improvements to the simulator and the STEP analysis tools for easier public use. In the nominal evaluation setting, our fully-open from-scratch model is on par with our prior closed-source work and substituting in the Qwen3-VL backbone leads to a strong multi-task table top manipulation policy outperforming our baseline by a wide margin. The VLA Foundry codebase is available at https://github.com/TRI-ML/vla_foundry and all multi-task model weights are released on https://huggingface.co/collections/TRI-ML/vla-foundry. Additional qualitative videos are available on the project website https://tri-ml.github.io/vla_foundry.

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BibTeX

@article{mercat2026vla,
  title = {VLA Foundry: A Unified Framework for Training Vision-Language-Action Models},
  author = {Jean Mercat and Sedrick Keh and Kushal Arora and Isabella Huang and Paarth Shah and Haruki Nishimura and Shun Iwase and Katherine Liu},
  year = {2026},
  abstract = {We present VLA Foundry, an open-source framework that unifies LLM, VLM, and VLA training in a single codebase. Most open-source VLA efforts specialize on the action training stage, often stitching together incompatible pretraining pipelines. VLA Foundry instead provides a shared training stack with end-to-end control, from language pretraining to action-expert fine-tuning. VLA Foundry supports both from-scratch training and pretrained backbones from Hugging Face. To demonstrate the utility of ou},
  url = {https://arxiv.org/abs/2604.19728},
  keywords = {cs.RO, cs.AI, cs.CV, cs.LG, cs.SE},
  eprint = {2604.19728},
  archiveprefix = {arXiv},
}

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