FaithEyes-7B-RL

This is the final reinforcement-learning (RL) checkpoint of FaithEyes, the main model reported in the paper. It is obtained by running GRPO on top of the FaithEyes-7B-SFT cold-start model, with the base model Qwen2.5-VL-7B-Instruct.

FaithEyes: Towards Faithful Tool Use via Multi-Agent Process-Image Self-Verification

Haoqing Wang, Xingrun Xing, Ziheng Li, Jianyuan Guo, Yehui Tang

📖 Model Description

FaithEyes is a multi-agent self-judging framework for agentic vision-language models (VLMs). A single VLM plays two roles: a main agent that solves the visual question by interleaving reasoning with executable code-based tool calls, and a subagent that judges whether each process image (e.g. a crop) produced by the main agent is helpful for answering the question. The verdict {"is_helpful": true/false, "reasons": ...} is both injected into the tool observation to steer subsequent reasoning and used to scale the tool reward by the helpful-tool ratio, suppressing reward hacking.

This is the final RL checkpoint and the primary model of the paper. The RL stage (GRPO) is what drives the model from merely imitating demonstrations to autonomously producing faithful tool calls — i.e. calls that genuinely capture the queried target — rather than decorative ones. It combines four reward terms: accuracy, format, consistency, and a faithfulness-targeting tool reward $r_{\mathrm{tool}} = 1 - (n_{\mathrm{fail}} + n_{\mathrm{unhelpful}}) / n_{\mathrm{tool}}$ that scales the bonus by the helpful-tool ratio. Crucially, the tool reward is accuracy-independent: it always credits an executable and helpful call and always penalizes a failed one, which keeps both the code-failure ratio and tool usage stable throughout training (an accuracy-gated variant degenerates into tool avoidance).

The self-judging subagent is instantiated by the model itself (under a separate prompt), so the judgement is available at inference with no external model dependency, keeping train–test consistency.

📚 Citation

If you find this work useful, please consider citing:

@article{wang2026faitheyes,
  title={FaithEyes: Towards Faithful Tool Use via Multi-Agent Process-Image Verification},
  author={Wang, Haoqing and Xing, Xingrun and Xia, Wei and Li, Ziheng and Tang, Yehui},
  journal={arXiv preprint arXiv:2607.28225},
  year={2026}
}