Underdog’s creator describes an AI OS powered by a fully local 4B-parameter model

Underdog’s creator says Woof 1.1 runs entirely on-device, has 4 billion parameters, takes up less than 2.5GB and handles browser use, tool calls and long tasks. The creator credits Greyhound, an inference engine built for Apple Silicon, with fast, power-efficient operation.

In the September 12, 2026 announcement, the creator called Woof 4B “on par with GPT 5.0 on things we care about” and said the team was working toward matching current frontier-model performance fully locally on consumer devices by the end of 2026.