What is the Agent2Agent (A2A) protocol?
The Agent2Agent (A2A) protocol is an open standard, introduced by Google in 2025, that lets AI agents built by different vendors discover each other's capabilities, exchange messages and coordinate tasks securely. It complements MCP, which connects agents to tools and data.
Key concepts
| Concept | Meaning |
|---|---|
| Agent card | Describes an agent's skills |
| Task | Unit of work between agents |
| Messages | Exchanged during a task |
| Artifacts | Outputs |
A2A vs MCP
| MCP | A2A | |
|---|---|---|
| Connects | Agent to tools/data | Agent to agent |
| Example | Read a ticket | Ask a billing agent to refund |
Use case
A support agent hands a refund task to a finance agent from another vendor.
