A2A — The Agent-to-Agent Protocol
Google announced A2A in April 2025; by April 2026 the spec is at https://a2a-protocol.org/latest/specification/ and 150+ organizations back it. A2A is the horizontal complement to MCP (Lesson 13): where MCP is vertical (agent ↔ tools), A2A is peer-to-peer (agent ↔ agent). It defines Agent Cards (discovery), tasks with artifacts (text, structured data, video), opaque task lifecycles, and auth. Production systems increasingly pair MCP with A2A. Google Cloud rolled A2A support into Vertex AI Agent Builder during 2025-2026.
This lesson isn’t interactive yet.
It is part of the curriculum and will get the same treatment as Phase 1 — a visual cover, hands-on labs, derivations with numeric checks and a quiz. Until then, the original lesson is the best place to read it:
Part of Phase 16 — Multi-Agent & Swarms. Use the previous / next cards below to keep browsing the phase.