A2A

• A2A (Agent-to-Agent) is an open standard proposed by Google for enterprise-scale agent ecosystems
• Enables seamless communication and collaboration between AI agents, irrespective of their underlying frameworks or provider-specific implementations
• Now governed under the Linux Foundation (Apache 2.0)
• Github: a2aproject/A2A
  • 20k stars

( What is A2A?)

• Agent Misrepresentation — developers wrap agents as simple tools, which is fundamentally limiting as it fails to capture the agent’s full capabilities and reasoning potential
• Custom Integration Overhead — without standards, each agent interaction requires bespoke point-to-point solutions
• Scalability Challenges — systems become difficult to maintain as agent interactions multiply
• Security Gaps — ad hoc communication lacks consistent security measures
• Limited Interoperability — prevents organic formation of complex AI ecosystems

( What is A2A?)

• Simplicity — leverages existing standards (HTTP, JSON-RPC, SSE) rather than inventing new technologies
• Enterprise Readiness — incorporates authentication, authorization, security, privacy, tracing, and monitoring
• Asynchronous Support — natively handles long-running operations and streaming for disconnected agents
• Modality Independent — agents communicate using a wide variety of content types
• Opaque Execution — agents collaborate without exposing internal logic, memory, or proprietary tools

( A2A Key Concepts)

• User — end party initiating requests, either human or automated service
• A2A Client (Client Agent) — application, service, or another AI agent acting on behalf of the user
• A2A Server (Remote Agent) — exposes HTTP endpoints implementing A2A; operates as an opaque system, internal workings hidden from clients

( What is A2A?)

• A2A — inter-organizational agent-to-agent communication
• MCP — model-to-data/resource connections (stateless tool integration)
• Frameworks — agent construction toolkits (ADK, LangGraph, Crew AI)
• Models — LLM reasoning foundation

• A2A Key Concepts
  • Core data model: Agent Card, Task, Message, Part, Artifact, ContextId
• A2A Request Lifecycle
  • 4-phase request flow: discovery, authentication, message sending, streaming
• A2A vs MCP
  • Detailed comparison of A2A and MCP protocols