STEER: Structured Text Editing via Edit-Chain Reinforcement Learning

Yucheng Lin, Jiaojiao Jiang


Abstract
Text detoxification is increasingly used in content moderation and dialogue systems, where systems must produce safe rewrites while revealing what was changed and why. Existing approaches typically trade off interpretability and end-to-end optimization. Monolithic rewriting methods treat detoxification as a single opaque generation step, whereas edit-based pipelines make edits explicit but are trained in separate stages, preventing joint optimization. We propose STEER, a framework that models detoxification as a structured edit chain formulation and optimizes the entire editing process end-to-end with Group Relative Policy Optimization (GRPO). To make this formulation trainable, we construct synthetic edit-chain supervision using a multi-agent pipeline, perform supervised fine-tuning (SFT) to teach the model the structured editing format, and then apply GRPO with a veto-aligned multiplicative reward and granular format scoring. Experiments on ParaDetox and two out-of-domain benchmarks show that STEER achieves the highest aggregate J score among the compared systems on ParaDetox and remains competitive under out-of-domain evaluation.
Anthology ID:
2026.findings-emnlp.166
Volume:
Findings of the Association for Computational Linguistics: EMNLP 2026
Month:
October
Year:
2026
Address:
Budapest, Hungary
Editors:
Hung-Yi Lee, Sunipa Dev, Jessy Li, Desmond Elliott
Venue:
Findings
SIG:
SIGDAT
Publisher:
Association for Computational Linguistics
Note:
Pages:
3516–3528
Language:
URL:
https://aclanthology.org/2026.findings-emnlp.166/
DOI:
Bibkey:
Cite (ACL):
Yucheng Lin and Jiaojiao Jiang. 2026. STEER: Structured Text Editing via Edit-Chain Reinforcement Learning. In Findings of the Association for Computational Linguistics: EMNLP 2026, pages 3516–3528, Budapest, Hungary. Association for Computational Linguistics.
Cite (Informal):
STEER: Structured Text Editing via Edit-Chain Reinforcement Learning (Lin & Jiang, Findings 2026)
Copy Citation:
PDF:
https://aclanthology.org/2026.findings-emnlp.166.pdf