Patient education is a major NLP application, but current evaluation largely focuses on text-only assistance. In radiology, this overlooks an important part of clinical communication: patients often need both a plain-language explanation and a visual aid showing where to look and what it refers to. We introduce MediSketch, a multimodal patient-education task in which an agent must produce an image–text bundle: an educational image and a grounded plain-language explanation. We instantiate this setting with a clinician-curated radiology testbed, a structured multimodal rubric, and a rubric-following judge that evaluates bundle quality rather than text-only correctness. Under a matched image-generation budget, we compare three test-time scaling strategies: parallel sampling, sequential revision, and hybrid search. Across five backbone models, the no-scaling baseline remains weak, while naive parallel search often provides little gain despite using the full budget. Hybrid performs best on 4 of 5 backbones, suggesting that test-time compute works best when exploration and revision are combined. Further analysis identifies weak multimodal self-critique as a major bottleneck: many models stop revising too early and overestimate the quality of their own image–text outputs. MediSketch exposes both an evaluation gap in multimodal patient education and a concrete failure mode in test-time scaling.

Most adults can complete a sequence of steps to achieve a certain goal, such as making a sandwich or repairing a bicycle tire. In completing these goal-oriented tasks, or simply tasks in this paper, one must use sequential reasoning to understand the relationship between the sequence of steps and the goal. LLMs have shown impressive capabilities across various natural language understanding tasks. However, prior work has mainlyfocused on logical reasoning tasks (e.g. arithmetic, commonsense QA); how well LLMs can perform on more complex reasoning tasks like sequential reasoning is not clear. In this paper, we address this gap and conduct a comprehensive evaluation of how well LLMs are able to conduct this reasoning for tasks and how they scale w.r.t multiple dimensions(e.g. adaptive prompting strategies, number of in-context examples, varying complexity of the sequential task). Our findings reveal that while Chain of Thought (CoT) prompting can significantly enhance LLMs’ sequential reasoning in certain scenarios, it can also be detrimental in others, whereas Tree of Thoughts (ToT) reasoning is less effective for this type of task. Additionally, we discover that an increase in model size or in-context examples does not consistently lead to improved performance.