China Telecom Huawei Technologies Beijing University of Posts and Telecommunications Tsinghua AsiaInfo Technologies (China) Inc This document defines a protocol suite and architectural framework for secure and scalable multi-agent collaboration. The proposed Multi-Agent Collaboration Protocol (MACP) enables trusted agent onboarding, capability-based query, distributed capability synchronization, and secure interaction among agents and external resources. The architecture introduces key entities such as the Agent Management Center (AMC), Agent Gateway (AGW), Agents, and External Resource Services (ERS), along with a set of protocols that collectively support dynamic, capability-driven collaboration across administrative domains.