How to use from
vLLM
Install from pip and serve model
# Install vLLM from pip:
pip install vllm
# Start the vLLM server:
vllm serve "OS-Copilot/OS-Shepherd-9B"
# Call the server using curl (OpenAI-compatible API):
curl -X POST "http://localhost:8000/v1/chat/completions" \
	-H "Content-Type: application/json" \
	--data '{
		"model": "OS-Copilot/OS-Shepherd-9B",
		"messages": [
			{
				"role": "user",
				"content": [
					{
						"type": "text",
						"text": "Describe this image in one sentence."
					},
					{
						"type": "image_url",
						"image_url": {
							"url": "https://cdn.britannica.com/61/93061-050-99147DCE/Statue-of-Liberty-Island-New-York-Bay.jpg"
						}
					}
				]
			}
		]
	}'
Use Docker
docker model run hf.co/OS-Copilot/OS-Shepherd-9B
Quick Links

OS-Shepherd-9B

OS-Shepherd-9B is an open multimodal reward model for judging computer-use agent trajectories. Given a task instruction, screenshots, and the agent's reasoning and actions, it determines whether the task was completed and returns a reasoned SUCCESS or FAIL verdict.

It is fine-tuned from Qwen3.5-9B on OS-Shepherd-100K using SFT followed by GRPO, with the RL stage focused on reducing false-success judgments.

Results

Benchmark Accuracy Fail recall
OSReward 86.1 86.0
OSReward-Hard 60.2 57.6

Results use the fixed judging protocol described in the OSReward paper.

Usage

Use the canonical prompt and trajectory format from the OSReward repository. A recent Transformers, vLLM, or SGLang version with Qwen3.5 multimodal support is required.

This model is intended for trajectory evaluation, data filtering, and reward-model research. It is not a computer-control policy and may still miss fine-grained visual failures, especially on hard cases.

License

Apache License 2.0. See LICENSE.

Citation

@article{sun2026osreward,
  title={OSReward: Instituting Standardized Evaluation for Cross-Platform Computer-Use Reward Models},
  author={Sun, Qiushi and others},
  journal={arXiv preprint arXiv:2607.28609},
  year={2026}
}
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