Cua's RL-Trained Decision Model Hits 92.9% on GUI-360, Open-Sourced
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1/ Today we're introducing Cua-S1-4B-0.2, the first multimodal decision model trained with RLOO on live computer-use tasks, using task-completion rewards. Text and multimodal adapters are available under Apache-2.0: https://t.co/0R5fWjfpGg
2/ At each step, the CUA-S1 model receives the screen state, the task goal, and a fixed set of candidate actions. It returns one action. The environment changes, and the next step starts from the new state.

3/ The training recipe has two stages. Supervised training teaches the decision format. Agentic RL then runs the model in live cua-bench-basic environments, where only a completed task earns the environment's reward.

4/ On the same held-out tasks, Cua-S1-4B-0.2 completes 17/18 text episodes and 13/18 multimodal. Zero-shot djev completes 16/18 and 12/18.

Context
Cua released Cua-S1-4B-0.2, which it calls the first decision model trained with RLOO, a reinforcement-learning method, on live computer-use tasks with task-completion rewards. At each step the model receives the screen state, the task goal and a fixed list of candidate actions, and returns one. Training first teaches that output format with supervised learning, then runs the model in live task environments where only a completed task earns reward.
Cua reports 92.9% versus 60.1% for an untrained djev baseline on a frozen 168-task multimodal split of GUI-360, an existing of Windows office application tasks, with the same inputs and scoring and no accessibility tree. Its other results, 17/18 versus 16/18 text episodes and 13/18 versus 12/18 multimodal, come from Cua's own held-out tasks and differ by one episode. Cua released Apache 2.0 adapters and training code, so others can check the numbers, which remain Cua's own.
- multimodal — A model that works with more than text — reading images, audio, or video, and sometimes generating them too.
- benchmark — A standard public test set for comparing AI models — the shared scoreboards behind every "model X beats model Y" claim.
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