This paper proposes shortcut decoding, an efficient framework for accelerating Chain-of-Thought (CoT) reasoning in Large Language Models (LLMs). Existing methods that prune or employ early stopping to reduce latency often compromise reasoning reliability. Motivated by the observation that LLMs frequently converge to correct solutions internally before completing explicit textual reasoning, we propose a dual-signal adaptive controller that integrates lightweight probes over internal hidden states with step-level entropy. This controller detects convergence of reasoning during generation and adaptively selects between a fast-exit path and a stability-verified path to remove redundant steps while preserving answer correctness. Experiments across multiple mathematical reasoning benchmarks demonstrate that shortcut decoding reduces token usage by approximately 35%, maintains accuracy comparable to full CoT decoding, and achieves final-answer accuracy comparable to the full CoT baseline, outperforming existing early-stopping methods without updating the base model. Our code is available at https://github.com/kuromi9527/shortcut_decoding.

Generating logically coherent video from text (T2V) for reasoning-intensive tasks like mathematical problem-solving presents a significant challenge for Vision-Language Models (VLMs). Therefore, we introduce VisualEDU, a benchmark based on Manim package to rigorously evaluate VLM capabilities in producing coherent, step-by-step video solutions for educational purposes, with a framework that integrates meta-prompt learning, visual and code feedback, and a modular drawing toolkit to enhance output quality. Novel metrics for temporal consistency, logical correctness, and visual clarity are proposed, and extensive experiments across nine VLMs reveal that while advanced proprietary models show promise, all struggle significantly with increasing task complexity (e.g., the performances of Claude-3.7-Sonnet and GPT-4o are below 56% on difficult tasks ), highlighting limitations in code generation, visual feedback correction and precise tool invocation. VisualEDU offers a robust platform for systematic T2V assessment in reasoning-intensive domains and guides future VLM improvements in this area.