Glossary
A2A Protocol
Agent-to-Agent (A2A) is an open protocol, originated by Google and now under the Linux Foundation, for peer-to-peer communication between independent agents owned by different teams or vendors. Agents publish capabilities via Agent Cards and exchange work through stateful Tasks. Distinct from MCP, which governs agent-to-tool access, not agent-to-agent.
Most systems described as "multi-agent" today are actually one team's orchestrator calling tools in sequence. A2A earns its place only when agents cross a boundary you don't own.
Where this comes up
AI Agent Failure Modes in Production
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