Bub provides a small Python runtime for creating AI agents in multi-agent settings where humans and agents work together. It implements a hook-based architecture where every turn stage is a pluggable hook, allowing developers to override or replace any part of the pipeline. Built on agents.md and Agent Skills standards, the same runtime powers CLI interactions, Telegram channels, and custom integrations. Context is managed through append-only tape records rather than mutable session state, making agent behavior easier to inspect and replay.