ChatGPT started as a chatbot and tech demo for OpenAI’s large language models (LLMs). It’s now something closer to a general-purpose AI platform—one that can search the web, generate images, write code, reason through complex problems, and execute multi-step actions across apps. As OpenAI has kept pushing ChatGPT forward with new models and features, a question that sounds simple has gotten surprisingly hard to answer: How does ChatGPT work?