# RT-2 / RT-X, brain

Google DeepMind's foundational 2023 research VLA. RT-2 is a transformer VLA trained on web text and images that directly outputs robot actions. Instantiations on PaLM-E and PaLI-X. RT-2-X is a 55B-parameter variant. Chain-of-thought reasoning for long-horizon planning. Superseded by Gemini Robotics for commercial paths, but conceptually ancestral to GR00T, Helix, pi0, and the broader dual-system descendants.

- **Slug:** rt-2
- **Type:** Research model
- **Maturity (DEPLOY ladder):** Research
- **Open source:** no

## Architecture

Transformer VLA trained on web text and images, directly outputs robot actions. Instantiations on PaLM-E and PaLI-X. RT-2-X is 55B parameters. Chain-of-thought reasoning for long-horizon planning. Trained on web data plus Open X-Embodiment.


## Key facts

- **Significance:** First-of-its-kind VLA; demonstrated VLMs can become VLAs
- **Ancestry:** Conceptual ancestor of the GR00T / Helix / pi0 dual-system descendants
- **Powered platforms:** Research robot platforms; not a commercial-deployment brain
- **Successor:** Superseded by Gemini Robotics in DeepMind's commercial roadmap


## Developed by (1)

- [Google DeepMind](/companies/google-deepmind.md)


## Sources (2)

1. **Google DeepMind Blog: RT-2 (primary)** · https://deepmind.google/blog/rt-2-new-model-translates-vision-and-language-into-action/
2. **Google Blog: RT-2 coverage** · https://blog.google/


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