Developer’s Guide to AI Agent Protocols- Google Developers Blog

This post introduces four new protocols for AI agent development: Model Context Protocol (MCP) for standardized server connections and tool discovery, Agent2Agent (A2A) for inter-agent communication and discovery via Agent Cards, Universal Commerce Protocol (UCP) for standardizing shopping lifecycles with typed schemas, and Agent Payments Protocol (AP2) for transaction authorization and auditing. It demonstrates their practical application using the Agent Development Kit (ADK) to build a multi-step supply chain agent for a restaurant, showcasing how these protocols reduce custom integration code and enable agents to interact with real systems, other agents, and financial transactions.