QUEST-35B-MT

This is the mid-training only checkpoint of QUEST-35B-A3B (Qwen3_5MoeForConditionalGeneration). It has not been fine-tuned with SFT or RL and therefore does not have the instruction-following or tool-use capabilities required to complete deep research tasks.

It is released as an intermediate artifact for research purposes (e.g., initializing further fine-tuning experiments or studying the effect of mid-training). If you need a usable deep research agent, please use QUEST-35B-MT+SFT or QUEST-35B-RL instead.

Training stage

Stage	Applied
Mid-training (MT)	✓
Supervised fine-tuning (SFT)	✗
Reinforcement learning (RL)	✗

Benchmark results

Not reported — this model lacks task-completion capability without SFT.

QUEST Family

Type	Resources
35B checkpoints	RL, MT+SFT, MT, SFT
30B checkpoints	RL, MT+SFT, SFT
Smaller checkpoints	9B, 4B, 2B
Training data	RL data, SFT objective data, SFT open-ended data, Mid-training data

Model selection note: if you only need to evaluate objective tasks and do not need open-ended task evaluation, we recommend the MT+SFT checkpoints because they perform better on reasoning-heavy objective benchmarks. For a more comprehensive evaluation across both objective and open-ended tasks, we recommend the RL checkpoints.

Quick start

from transformers import AutoModelForCausalLM, AutoTokenizer

model_id = "osunlp/QUEST-35B-MT"
tokenizer = AutoTokenizer.from_pretrained(model_id)
model = AutoModelForCausalLM.from_pretrained(
    model_id, device_map="auto", torch_dtype="auto",
)

License

Released under the Apache License 2.0.

Citation

If our paper or related resources prove valuable to your research, we kindly ask for a citation.

@misc{xie2026quest,
  title={QUEST: Training Frontier Deep Research Agents with Fully Synthetic Tasks},
  author={Xie, Jian and Lin, Tianhe and Wang, Zilu and Ning, Yuting and Yao, Yuekun and Xue, Tianci and Zhang, Zhehao and Li, Zhongyang and Zhang, Kai and Wu, Yufan and Chen, Shijie and Gou, Boyu and Han, Mingzhe and Wang, Yifei and Lee, Vint and Wei, Xinpeng and Wang, Xiangjun and Su, Yu and Sun, Huan},
  journal={arXiv preprint arXiv:2605.24218},
  year={2026}
}