A2A Protocol: The Open Standard for Agent-to-Agent Communication

The Agent-to-Agent (A2A) protocol is the open communication standard that enables autonomous AI agents to discover, delegate, and collaborate peer-to-peer — no central broker required.

Why A2A Matters

MCP (Model Context Protocol) solved how a single LLM connects to tools. But what happens when one agent needs to hand off work to another? That's where A2A comes in.

Protocol Overview

• Agent Discovery — Machine-readable Agent Cards at /.well-known/agent-card.json
• Task Delegation — HTTP POST /a2a/v1/tasks with structured goal
• Streaming Results — Server-Sent Events for real-time progress
• Artifact Exchange — Structured return values (code, files, API responses)
• Push Notifications — Webhook callbacks for long-running tasks

Production at Scale

OpenSIN runs 100+ agents on A2A across 18 teams. Any agent in any language (Python, TypeScript, Go, Rust) can implement A2A.