This study is a randomized controlled trial (RCT) investigating whether access to a new LLM interface can improve medical triage and diagnostic accuracy for laypeople compared to access to a standard LLM interface. It addresses previous findings where laypeople using standard LLMs performed worse than those using conventional methods (e.g., web search) due to incomplete symptom sharing and poor interpretation of AI advice. To address this, the research tests a structured LLM system that proactively asks clinical history questions before providing a standardized, easy-to-read diagnostic output.