The author has built an AI system called Echo, which combines the outputs of multiple open-weight models to achieve better results than any individual model. Echo decides how much computation to allocate, which models to use, and how to combine their outputs for each request. The system has been evaluated on a set of benchmarks and has achieved results comparable to Fable, a stronger comparison system, at around one third of the inference cost. The author has made a chat interface and API available for testing.