UniCreative: Unifying Long-form Logic and Short-form Sparkle via Reference-Free Reinforcement Learning
Paper · 2026 · Xiaolong Wei, Zerun Zhu, Simin Niu et al.
Summary
LLM creative writing faces two opposite problems. Long stories and scripts need global planning, or they drift off topic, repeat themselves and lose structure. Short pieces such as poems, slogans or blessings get worse when forced through rigid outlines, and models already tend toward bland, high-probability wording. The authors propose UniCreative, a reinforcement learning framework in which a single policy decides for itself whether to outline first (Plan-then-Write) or to answer directly.
Training skips SFT and needs no ground-truth references. AC-GenRM, a generative reward model, writes evaluation criteria specific to each query and gives fine-grained preference judgments on response pairs. ACPO, a GRPO-based policy optimization method, turns these judgments into rewards over groups of sampled outputs.
On Qwen3 models (1.7B, 4B, 8B), AC-GenRM agrees closely with expert evaluators, and ACPO improves both long- and short-form writing. Larger models also learn to choose the right mode on their own, which the authors call emergent meta-cognition. The work points to a cheaper route to creative alignment that avoids expensive human-written data.
Key points
- Blessing short-text dataset: RL training raised the share of "excellent" ratings over the Thinking baselines.
- Qwen3-1.7B: 64.2% → 90.0%
- Qwen3-4B: 74.0% → 91.4%
- Qwen3-8B: 68.0% → 93.6%, slightly above Claude-Sonnet-4.5 (93.2%)
- Mode Discrimination Benchmark: the 4B and 8B models reach up to 96.4% accuracy on Easy items and 86.4% on Hard items when choosing between planning and direct generation.
- Smallest model: Qwen3-1.7B becomes worse at choosing the mode after RL (64.2% → 57.0%), even though its writing quality improves. The authors attribute this to limited model capacity.
- Compute cost: long-form training samples reach about 12.6k tokens, and training ran on 8 × NVIDIA H800 GPUs.
- Limitations and code: the switch between modes is strictly binary, so "medium-form" texts remain an open problem. Code is available at github.com/weixiaolong94-hub/UniCreative.
Institutions
Fields, topics and concepts
📚 Shelves 5The field of science this work belongs to (OpenAlex fields).Computer Science · 16,667 worksArtificial Intelligence · 16,194 worksArts and Humanities · 16,039 worksLanguage and Linguistics · 15,891 worksComputer Vision and Pattern Recognition · 2,869 works
Cite
Cite as Xiaolong Wei, Zerun Zhu, Simin Niu, Xingyu Zhang, Peiying Yu, Changxuan Xiao, Yuchen Li, Jicheng Yang, Zhejun Zhao, Chong Meng, Long Xia and Daiting Shi. 2026. UniCreative: Unifying Long-form Logic and Short-form Sparkle via Reference-Free Reinforcement Learning. Findings of the Association for Computational Linguistics: ACL 2026.
@inproceedings{wei2026unicreative,
title = {{UniCreative: Unifying Long-form Logic and Short-form Sparkle via Reference-Free Reinforcement Learning}},
author = {Xiaolong Wei, Zerun Zhu, Simin Niu, Xingyu Zhang, Peiying Yu, Changxuan Xiao, Yuchen Li, Jicheng Yang, Zhejun Zhao, Chong Meng, Long Xia and Daiting Shi},
booktitle = {Findings of the Association for Computational Linguistics: ACL 2026},
year = {2026},
doi = {10.18653/v1/2026.findings-acl.1179},
url = {https://doi.org/10.18653/v1/2026.findings-acl.1179}
}References
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