A Compound AI System is a computer system that performs a task using more than just one AI component. While a common component is a trained machine learning model, such as a Large Language Model, the number and nature of components vary widely depending on the task. For example, a compound system that solves coding challenges can be based on two main components: an LLM that generates variations of coding solutions, and a code execution module, which tests for accuracy and evaluates the performance of the proposed solutions.