Diffusion-model RL stops scoring whole answers: part-of-speech credit lifts MATH500 by 9.0 points over the base model at the smallest budget
Diffusion language models commit tokens over many denoising steps, so a whole-response reward says little about which tokens helped later refinement. DTCA estimates each token's contribution from the confidence gain at still-masked positions after that token is committed, averages these signals by part-of-speech category into stable weights, and uses them to pick denoising timesteps and assign token-level learning signals, with entropy-based calibration. On LLaDA-8B-Instruct it beats the base model at generation budgets of 128, 256 and 512, by 9.0, 6.8 and 4.8 points on MATH500 and 5.3, 2.1 and 2.5 points on GSM8K.