---
type: Glossary Term
title: "Agent2Agent (A2A)"
description: "Agent2Agent (A2A) is an open protocol—launched by Google in April 2025 and stewarded by the Linux Foundation Agentic AI Foundation (AAIF)—for peer-to-peer communication and task delegation between opaque autonomous agents across organizational boundaries."
resource: "https://agenticweb.wiki/terms/agent-to-agent/"
tags: ["glossary", "coordinate"]
status: stable
generated: { by: agenticweb-builder/1.0, at: 2026-10-23T00:00:00Z }
verified: { by: process:agenticweb-engine, at: 2026-10-23T00:00:00Z }
stale_after: 2026-11-22T00:00:00Z
sources:
  - id: ref-1
    resource: "https://a2a-protocol.org/latest/specification/"
    last_modified: 2026-09-05T00:00:00Z
  - id: ref-2
    resource: "https://aaif.io/blog/a2a-joins-aaif"
    last_modified: 2026-09-05T00:00:00Z
---

# Agent2Agent (A2A)

**Agent2Agent (A2A)** is an open protocol—launched by Google in April 2025 and stewarded by the Linux Foundation Agentic AI Foundation (AAIF)—for peer-to-peer communication and task delegation between opaque autonomous agents across organizational boundaries. Where **MCP** connects a host model to tools and data sources (Step 5: Act), **A2A** coordinates multi-turn, potentially long-running **Tasks** between independent agents (Step 6: Coordinate) that discover each other via `/.well-known/agent-card.json`, exchange typed `Part` messages and output `Artifact` objects, and stream updates over SSE or webhook push notifications without exposing internal memory or prompts. Used by: a2a.

# Knowledge Graph

* **Related standards**: [Agent2Agent Protocol](/okf/protocols/a2a.md), [Model Context Protocol](/okf/protocols/mcp.md)

[^ref-1]: https://a2a-protocol.org/latest/specification/ (https://a2a-protocol.org/latest/specification/)
[^ref-2]: https://aaif.io/blog/a2a-joins-aaif (https://aaif.io/blog/a2a-joins-aaif)