Ai2 open-sources MolmoAct 2 fully — code, training data, 400K+ downloads

DJiafei · x · 2026-09-26

Ai2 released MolmoAct 2, an open foundation model for real-world robots, and on May 28 fully open-sourced it: fine-tuning scripts, every training dataset, all evaluation rollouts, and the tokenizer training recipe.
Inference and training are now integrated into Hugging Face's LeRobot platform, so existing teams can drop it in without retooling.
Artifacts have been downloaded 400K+ times in weeks. Ai2 argues open robotics advances only when researchers can evaluate and customize models themselves.
MolmoAct 2 extends last year's Action Reasoning Model concept — reasoning about the environment in 3D before acting — targeting reliable long-duration chores like loading dishwashers or prepping lab samples.

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