titleWhen Confidence Misleads: Suffix Anchoring and Anchor-Proximity Confidence Modulation for Diffusion Language Models
authorsJungwon Park, Jimyeong Kim, Jungmin Ko, Nojun Kwak, Wonjong Rhee
date2026-05-27
venuearXiv (preprint, not peer reviewed)
idarXiv:2605.28181
affiliationSeoul National University
upvotes1 (Hugging Face Daily Papers, 2026-11-01)
linksabs pdf hf
abstractDiffusion language models decode text by iteratively denoising masked token sequences, making the choice of which positions to decode a central inference-time decision. Most training-free decoding strategies use model confidence for position selection, assuming that high-confidence positions are ready to be decoded. In this work, we revisit this assumption by studying when confidence misleads fully non-autoregressive (fully non-AR) decoding. EOT tokens can receive high confidence and cause incomplete generation; inserting a suffix anchor can mitigate this issue but introduces local overconfidence near the anchor, causing anchor-adjacent tokens to be decoded too early. To address these issues, we propose Suffix-Anchored Confidence Modulation, a simple training-free method that inserts a short suffix anchor to encourage response completion and modulates confidence near the anchor according to decoding progress. This preserves the response-completion benefit of suffix anchoring while reducing premature decoding of anchor-adjacent tokens. Across text-only reasoning, vision-language reasoning, and code-generation benchmarks, our method consistently improves confidence-based fully non-AR decoding, outperforms explicit EOT suppression, and preserves the parallel decoding advantage of fully non-AR generation.

cite

@misc{park2026when,
  title={When Confidence Misleads: Suffix Anchoring and Anchor-Proximity Confidence Modulation for Diffusion Language Models},
  author={Jungwon Park and Jimyeong Kim and Jungmin Ko and Nojun Kwak and Wonjong Rhee},
  year={2026},
  eprint={2605.28181},
  archivePrefix={arXiv},
  url={https://arxiv.org/abs/2605.28181}
}