Online reinforcement learning (RL) serves as an effective method for enhancing the capabilities of Android agents. However, guiding agents to learn through online interaction is prohibitively expensive due to the high latency of emulators and the sample inefficiency of existing RL algorithms. We identify a fundamental limitation in current approaches: the Single State Single Action paradigm, which updates the policy with one-to-one state-action pairs from online one-way rollouts without fully exploring each costly emulator state. In this paper, we propose Android Coach, a novel framework that shifts the training paradigm to Single State Multiple Actions, allowing the agent to sample and utilize multiple actions for a single online state. We enable this without additional emulator overhead by learning a critic that estimates action values. To ensure the critic serves as a reliable coach, we integrate a process reward model and introduce a group-wise advantage estimator based on the averaged critic outputs. Extensive experiments demonstrate the effectiveness and efficiency of Android Coach: it achieves 7.5% and 8.3% success rate improvements on AndroidLab and AndroidWorld over UI-TARS-1.5-7B, and attains 1.4x higher training efficiency than Single State Single Action methods PPO and GRPO at matched success rates.
Figures & tables
Figure 1: (Top): Online rollout time distribution based on the measured time on 8 parallel environments in training for 80 steps. (Bottom I): The conventional online rollout and critic training loop. The primary bottleneck is the high-latency environmental interaction, while the GUI agent action inference is relatively fast. (Bottom II): Standard agent update with Single State Single Action paradigm. Agent updates rely merely on the state-action pairs collected from the online rollout. (Bottom III): Android Coach update with Single State Multiple Actions paradigm. We fully leverage each expensive online state by generating multiple actions. The agent is then updated using this data. This approach improves training efficiency by gathering more training samples within the same online interaction cost.
Figure 2: Overview and pipeline for a training step in Android Coach . 1. Online Rollout: Policy interacts with parallel environments to collect complete trajectories. 2. Critic Update: Annotate state-action pairs with returns to train the value model. 3. Multiple sample: Resample multiple actions for each online state. 4. Actor Update: Compute action values and advantages with leave-one-out strategy, then update policy via gradient step.
Training Mode
Base Algorithm
Method
Advantage Estimation
Exploration Paradigm
Sample Efficiency
Offline
SFT
OS-Genesis Sun et al. (2025)
Reward-based
Static Data
N/A
Archer Zhou et al. (2024)
DigiQ Bai et al. (2025a)
Value-based
Static Data
N/A
Q-Learning Watkins and others (1989)
VEM Zheng et al. (2025)
Value-based
Static Data
N/A
DPO Rafailov et al. (2023)
UI-TARS-1.5 Qin et al. (2025)
Pairwise-Preference
Static Data
N/A
Hybrid
AWR Peng et al. (2019)
DigiRL Bai et al. (2025a)
Value-based
SSSA
Low
Online
GRPO Shao et al. (2024)
MobileRL Xu et al. (2025a) WebAgent-R1 Wei et al. (2025) ARPO Lu et al. (2025a)
Reward-based
SSSA
Low
Table 1: Comparison of representative GUI agent training frameworks. Android Coach is the first to achieve efficient Single State Multiple Actions (SSMA) exploration in an online setting, significantly improve sample efficiency with limited interaction costs compared to standard Single State Single Action (SSSA) approaches. ACLOO refers to Actor-Critic Leave-One-Out we proposed in our method.
Figure 3: An overview of dataset construction pipeline for process reward model training.
Models
#Params
AndroidLab SR (%)
AndroidWorld SR (%)
QD
OP
Average
Easy
Mid
Hard
Average
Proprietary Models
Gemini-Pro-1.5 (SoM) Team et al. (2024)
-
-
-
16.7
-
-
-
22.8
GPT-4o (SoM) OpenAI et al. (2024)
-
-
-
31.2
-
-
-
34.5
Claude-Sonnet-4 (SoM) Anthropic (2025)
-
-
-
40.6
-
-
-
41.0
UI-Genie-Agent Xiao et al. (2025)
72B
-
-
41.2
-
-
-
-
Table 2: Success rates of proprietary and open-source models on AndroidWorld and AndroidLab for mobile GUI interaction tasks. QD is the abbreviation for the query detect type, and OP is the abbreviation for the operation type. Standard deviations are reported in gray subscripts for all models except proprietary ones.
Figure 4: Training efficiency analysis of different methods over training time. We report the relationship between training time and (a) interaction times, (b) sampled actions number, and (c) success rate. The GRPO group size and sample number of Android Coach are both 4. Data is collected on AndroidWorld over UI-TARS-1.5-7B.
Figure 5: The effect of the ACLOO advantage estimation. (a) The training reward curves. (b) The final success rate gain on AndroidLab.
Single State N Actions
Training Time
AndroidLab SR(%)
AndroidWorld SR(%)
number of N
1
1.00x
34.8 ±0.7
36.8 ±1.3
2
1.22x
35.5 ±1.2
38.5 ±2.2
4
1.62x
37.0 ±0.7
39.1 ±0.5
8
2.18x
37.0 ±0.0
39.4 ±2.0
Table 3: Analysis of action rollout times. We report total training time and success rates on AndroidLab and AndroidWorld across different numbers of samples.
Figure 6: Critic loss with different initialization strategies during joint policy optimization.
Usage of PRM
SR
ROR
Average Steps
AndroidLab
wo/ PRM
37.0
83.2
12.7
w/ PRM
39.4 (+2.4)
89.8 (+6.6)
11.9 (-0.8)
AndroidWorld
wo/ PRM
39.1
80.0
13.0
w/ PRM
41.1 (+2.0)
85.1 (+5.1)
12.5 (-0.5)
Table 4: Analysis of PRM usage. We report the success rate (SR), reasonable operation ratio (ROR) of steps and average steps on AndroidLab for agent trained with and without process model.
Appendix figures & tables7 assets
Supplementary material from the paper’s appendix.
Appendix
Figure 7: Process Reward Model training data format.
Component
Hyperparameter
Value
Data
Max Prompt Length
32768
Data
Max Response Length
512
Data
Train Batch Size
8
Actor/Policy
Strategy (Parallelism)
FSDP2
Actor/Policy
PPO Micro Batch Size/GPU
1
Actor/Policy
Learning Rate (LR)
1e-6
Appendix
Table 5: Main hyperparameters in Android Coach .
Action
Definition
Click(x, y)
Clicks at coordinates (x, y).
Scroll(x1, y1, x2, y2)
Scrolls from (x1, y1) to (x2, y2).
Drag(x1, y1, x2, y2)
Drags from (x1, y1) to (x2, y2).
Type(content)
Types the specified content.
Wait()
Pauses for a brief moment.
Finished(content)
Marks the task as complete.
Appendix
Table 6: Operation action space for GUI agent in Android Coach .
Figure 8: Prompt for Android Coach . This prompt is consistent with the official prompt provided by UI-TARS-1.5-7B.
Figure 9: Prompt for outcome verifier.
Figure 10: Prompt for Process Reward Model.
Figure 11: Prompt for GPT-4o to generate reason for PRM Training.
GUI agents trained with reinforcement learning (RL) have showcased strong environment learning capabilities on mobile platforms. However, RL typically demands extensive real-environment interactions, leading to high resource costs and instability, especially in GUI scenarios. To address these, we propose WM-R1, the first reinforcement learning framework that trains mobile GUI agents with world models instead of real environments. Specifically, world models serve as the source of state transitions during all rollouts, replacing the real Android environment within the training loop. WM-R1 also embeds world models directly into the thinking process, enabling agents to reason about the consequences of candidate actions before committing to the final action. Crucially, WM-R1 eliminates the need for real-environment interaction, supports massively parallelized and step-level granularized trajectory generation grounded in world models, and introduces a multi-dimensional rule-based reward that jointly optimizes task success, trajectory efficiency, and world model utilization. For efficient training, we curate a high-quality dataset of 2000 challenging tasks. Experiments on Android mobile benchmarks demonstrate that WM-R1-trained agents significantly outperform GRPO-only baselines and inference-time simulation methods. Code is available at https://github.com/genalyu/WM-R1 .
Yu Han, Tianwen Qian
School of Computer Science and Technology, East China Normal University
Graphical user interface (GUI)-based mobile agents automate digital tasks on mobile devices by interpreting natural-language instructions and interacting with the screen. While recent methods apply reinforcement learning (RL) to train vision-language-model(VLM) agents in interactive environments with a primary focus on performance, generalization remains underexplored due to the lack of standardized benchmarks and open-source RL systems. In this work, we formalize the problem as a Contextual Markov Decision Process (CMDP) and introduce AndroidWorld-Generalization, a benchmark with three increasingly challenging regimes for evaluating zero-shot generalization to unseen task instances, templates, and applications. We further propose an RL training system that integrates Group Relative Policy Optimization (GRPO) with a scalable rollout collection system, consisting of containerized infrastructure and asynchronous execution % , and error recovery to support reliable and efficient training. Experiments on AndroidWorld-Generalization show that RL enables a 7B-parameter VLM agent to surpass supervised fine-tuning baselines, yielding a 26.1% improvement on unseen instances but only limited gains on unseen templates (15.7%) and apps (8.3%), underscoring the challenges of generalization. As a preliminary step, we demonstrate that few-shot adaptation at test-time improves performance on unseen apps, motivating future research in this direction. To support reproducibility and fair comparison, we open-source the full RL training system, including the environment, task suite, models, prompt configurations, and the underlying infrastructure \footnote{https://github.com/zihuanjiang/AndroidWorld-Generalization}.
Li Gu, Zihuan Jiang, Zhixiang Chi +5
Mila – Québec AI Institute · Concordia University · University of Toronto +3
Computer-use agents must solve long-horizon tasks through repeated interaction with partially observable, multimodal desktop environments. Although imitation learning and offline trajectory refinement provide strong priors, static traces cannot cover the causal feedback loop of real computer use: each action changes the screen state, future action space, and recovery options. EvoCUA-1.5 extends self-evolving computer-use agents from offline experience learning to online reinforcement learning, where policies interact with executable sandbox environments and improve from verifiable task outcomes. Online RL in this setting requires more than directly reusing single-turn language-RL recipes. Multi-turn interaction introduces context-managed observations, sparse terminal rewards, variable-length trajectories, and slow environment feedback. EvoCUA-1.5 addresses these challenges with Step-Level Policy Optimization (STEPO), which preserves trajectory-level advantage balance after decomposition into step-level samples; policy-aware filtering and pass-rate calibration over verifiable synthesized tasks; Dynamic Tri-Adaptive Curriculum (DTAC), which combines learnable tasks, difficult positive replay, and controlled infeasible-task exposure; and a fully asynchronous RL infrastructure with staleness control and mini-group batching. Experiments show that these components improve training stability and downstream performance. EvoCUA-1.5 achieves 63.2% success on OSWorld-Verified, outperforming comparable 32B/35B-scale open-weight baselines and even approaching models with significantly larger parameter counts. Overall, EvoCUA-1.5 provides a practical framework for scaling online RL in multi-turn computer-use agents.
Mianqiu Huang, Taofeng Xue, Chong Peng +12
1Meituan · 2Fudan University · 3Shanghai Jiao Tong University +1