CUA-Master-27B  ·  Open-World Recursive Improvements

CUA-Master: Scaling Computer-use Agents through Open-World Recursive Improvements

A nested double-loop recursive framework that keeps expanding what computer-use agents can do.

Xinlei Yu, Gen Li, Ji Zhao, Zhangquan Chen, Congcong Wang, Shuai Dong, Zelin Peng, Yuqi Xu, Hongrui Wu, Kaiwen Tuo, Cheng Yang, Kaituo Feng, Yifan Wu, Jiayi Zhang, Dongming Wu, Wenqi Shao, Jiaqi Wang, Xiangyu Yue✉

MMLab, CUHK  ·  THU  ·  HKUST(GZ)  ·  Explore Academy, JD

80.2
OSWorld Verified
avg. score, GUI-only
36.9
OSWorld 2.0
avg. score, GUI-only
43.9
WeaveBench
avg. score, GUI + CLI
25.0
Agents’ Last Exam
full-pass rate, GUI + CLI
Overview

Competitive with far larger & closed-source models — at only 27B

CUA-Master-27B achieves competitive performance across GUI-only and GUI–CLI hybrid benchmarks, consistently outperforming similarly sized specialists and approaching markedly larger or closed-source models, while also executing tasks with fewer steps, fewer tokens, and less wall-clock time.

Performance comparison of CUA-Master-27B across four benchmarks
Performance comparisons of CUA-Master-27B and other counterparts across four benchmarks.
Abstract

Why open-world recursive improvement?

Development of computer-use agents (CUAs) remains constrained by the limited diversity, controllability, and reliability of interaction data. Conventional pipelines lack iterative feedback, while existing recursive approaches rely on self-generated experiences, limiting ability expansion and yielding diminishing returns. We introduce CUA-Master, a nested double-loop recursive improvement framework. At the system level, an outer world–data–model flywheel continuously incorporates open-world corpus and leverages evolving model weaknesses to guide subsequent data construction and optimization iterations. At the data level, an inner flywheel couples open-world seeding and autocatalytic propagation: the former mines authentic workflows as seed tasks from instructional videos with visual-semantic dual-path trajectory reconstruction; the latter transforms these seeds into reusable primitives for controllable synthesis of diverse, complex, and verifiable tasks. A feedback-guided snapshot-rollback retry mechanism further enables efficient and reliable trajectory collection in real environments.

Method

A double-loop recursive flywheel

CUA-Master double-loop recursive flywheel pipeline
The recursive flywheel (left) integrates open-world seeding (upper right) and autocatalytic propagation (lower right).
🌍

Open-world Seeding

Mines authentic workflows from instructional videos (YouTube, TikTok, Bilibili) via hierarchical corpus harvesting and seed task mining, then reconstructs trajectories with a visual-semantic dual-path mechanism — continuously injecting external knowledge beyond the model’s own capabilities.

⚗️

Autocatalytic Propagation

Abstracts seed tasks into reusable ability primitives and composes them into verifiable synthetic tasks, with explicit control over task complexity and application scope — from single-app to cross-app workflows.

🔁

Snapshot-Rollback Retry

Feedback-guided retries roll the environment back to the latest valid snapshot instead of restarting from scratch, preserving valid execution prefixes and substantially improving rollout success rate and efficiency.

8
domains
650+
applications
100+
CUA environments
2,000+
concurrent VMs
Hierarchical application taxonomy and representative applications
Hierarchical taxonomy (8 domains / 36 subdomains / 650+ apps) and representative applications across the eight domains.
Experiments

Strong performance, superior efficiency

Under a consistent benchmark protocol, CUA-Master-27B improves over UI-Mate-27B by +2.6 / +12.9 / +25.6 / +11.8 across the four benchmarks, and matches or surpasses Qwen-CUA-397B-A17B on hybrid settings despite being over an order of magnitude smaller. It also completes tasks with fewer steps and 24–36% less runtime than comparable models.

Method OSWorld Verified †OSWorld 2.0 †WeaveBench ‡Agents’ Last Exam ‡
Generalist
Qwen-3.5-27B54.60.813.51.3
Qwen-3.5-397B-A17B61.010.119.65.3
Qwen-3.6-27B61.48.916.55.3
Qwen-3.8-27B81.236.514.119.1
Qwen-3.8-Max82.844.729.225.0
Minimax-M3-428B-A23B68.323.0––
Kimi-K2.6-1T-A32B72.7––10.5
Kimi-K3-2.8T-A104B84.255.943.225.0
Seed-2.1-Pro *69.8––17.1
GPT-5.6-Luna *77.346.344.022.4
GPT-5.6-Sol *83.659.050.626.3
Claude-Sonnet-5 *79.0–40.8–
Claude-Opus-5 *86.364.255.728.3
Specialist
OpenCUA-72B59.3–––
GUI-Owl-1.5-32B58.1–––
EvoCUA-1.5-32B62.96.9––
ScaleCUA-9B69.8–––
Qwen-CUA-397B-A17B84.043.635.121.1
UI-Mate-27B77.624.018.313.2
CUA-Master-27B (Ours)80.236.943.925.0

Average scores (Agents’ Last Exam: full-pass rate). * closed-source models; † GUI-only evaluation; ‡ GUI+CLI hybrid assessment. Full table with per-task step / token / time metrics in the paper.

Efficiency comparison: score vs. wall-clock time
Performance–efficiency trade-off: score (y) vs. wall-clock runtime (x); bubble size denotes token consumption. CUA-Master sits in the favorable upper-left region.
🖥️

Cross-platform generalization

Without platform-specific tuning, CUA-Master-27B scores 56.2 on WindowsAgentArena, 43.0 on MacOSWorld, and 59.9 on MacAgentBench — generalizing across Linux, Windows, and macOS.

📈

Gains across iterations

The world–data–model flywheel exhibits continuous gains across recursive iterations, with SFT iterations progressively expanding abilities and a final RL stage breaking through the capability plateau.

🧪

Better data synthesis

The double-loop design substantially improves the diversity, coverage, reliability, and controllability of synthesized tasks and trajectories compared to unidirectional or closed-world pipelines.

Citation

BibTeX

@article{yu2026cuamaster,
  title   = {CUA-Master: Scaling Computer-use Agents through Open-World Recursive Improvements},
  author  = {Yu, Xinlei and Li, Gen and Zhao, Ji and Chen, Zhangquan and Wang, Congcong and Dong, Shuai
             and Peng, Zelin and Xu, Yuqi and Wu, Hongrui and Tuo, Kaiwen and Yang, Cheng and Feng, Kaituo
             and Wu, Yifan and Zhang, Jiayi and Wu, Dongming and Shao, Wenqi and Wang, Jiaqi and Yue, Xiangyu},
  journal = {arXiv preprint},
  year    = {2026}
}