In plain English
MCP connects an agent to tools and data. A2A connects an agent to other agents. It uses agent cards, tasks, messages and results so agents from different makers can cooperate. Open problems remain with trust, permissions, cost and errors. Start with one agent, and treat other agents' output as untrusted.
- A2A
- A standard for agents to hand tasks to each other.
- Agent card
- A short public description of what an agent can do.
- Hand-off
- Passing a task from one agent to another.
Picture it
MCP and A2A
MCP
- Agent to tool
- Calls a function or reads data
- A tool does one defined thing
- Like a worker using equipment
A2A