MolmoAct 2 / MolmoAct 2-Think
Fully open (weights, data, code) VLA from Ai2, the main open alternative to π0.5/GR00T for tabletop manipulation. Start from a fine-tuned checkpoint (e.g. allenai/MolmoAct2-DROID) for ready-to-run inference; the base card has no inference code.
Model idallenai/MolmoAct2
PricePrice not published
Checked29 September 2026
Where it stands
11newer robotics models since its release
- Praxis-130 Sep 2026
- Helix 2.517 Sep 2026
- UnifoLM-WLA-1.010 Sep 2026
- Skild S1 (Skild Brain)25 Aug 2026
- Generalist GEN-1.519 Aug 2026
The 5 newest are listed. All robotics models
- Weights
- Weights are public. Licence: Apache-2.0; model weights on HF. See the licence for commercial terms.
How to call it
3 ways to use MolmoAct 2 / MolmoAct 2-Think, with the model id each provider expects.
| Provider | Model id | Endpoint | Docs |
|---|---|---|---|
| Hugging Face | allenai/MolmoAct2 |
huggingface.co | |
| GitHub | github.com | ||
| Hugging Face LeRobot | allenai/MolmoAct2-LIBERO-LeRobot |
huggingface.co |
Pricing
Price not published.
No price source linked. Checked 29 September 2026.
Specs
- Input
- Text and images
- Output
- Robot actions
- Context window
- Not published
- Max output
- Not published
- Open weights
- Yes
- Licence
- Apache-2.0 (code); model weights on HF (license tag not stated on card)
- Released
- 5 May 2026
- Status
- Current
- Type
- Robotics model
What stands out
What its maker marketed at launch, and what people found later, each with its source.
Open action reasoning model
Molmo2-ER embodied-reasoning VLM connected to a flow-matching action expert via per-layer KV conditioning; the Think variant adds adaptive depth reasoning (interpretable depth map before acting).
Strong out-of-the-box real-world success
87.1% average success over 15 real Franka tasks vs 45.2% for π0.5 and 48.4% for MolmoBot (Ai2’s evaluation); LIBERO 97.2% (98.1% Think).
Fast inference
~180 ms per action call (790 ms with adaptive depth reasoning) vs ~6,700 ms for the original MolmoAct (up to 37x faster).
Largest open bimanual dataset
Released with MolmoAct2-BimanualYAM, 720+ hours of bimanual tabletop demonstrations, which Ai2 calls the largest open bimanual robotics dataset, plus an open FAST action tokenizer.
Notes
Checkpoints: MolmoAct2 (post-trained multi-embodiment foundation, ~5.4B params per HF safetensors), -Think, -Pretrain, fine-tuned -DROID, -BimanualYAM, -SO100_101, -LIBERO, -Think-LIBERO, FAST-Tokenizer. Main supported robots: SO-100/101, bimanual YAM, Franka (DROID); others need fine-tuning. Paper arXiv 2605.02881.
Sources: Ai2 blog, arXiv 2605.02881, HF model card, GitHub.