The Agent Communication Protocol (ACP) is a REST-based, open-source standard developed by IBM Research and governed by the Linux Foundation. Designed to solve the growing interoperability crisis among AI agents, ACP enables seamless communication, modularity, and composability in distributed AI systems. It supports multimodal messaging, offline discovery, asynchronous interactions, and simple HTTP integration—making it ideal for edge computing, secure inter-enterprise collaboration, and scalable AI orchestration.