Relationship & Integration with MCP

TL;DR: Agent applications often need both A2A and MCP. We recommend using MCP to connect tools and A2A to connect Agents.

Why Protocols?

The A2A Protocol complements Anthropic’s Model Context Protocol (MCP):

  • MCP: Focuses on providing tools and context support for agents.
  • A2A: Addresses the interoperability challenges in large-scale multi-agent system deployments.

Protocol Positioning

MCP’s Role

  • Connects agents with tools, APIs, and resources.
  • Provides structured input/output interfaces.
  • Standardizes “function calling” across models and frameworks.

A2A’s Role

  • Enables dynamic, multi-modal communication between agents.
  • Does not require shared memory, resources, or tools.
  • Community-driven open standard.

Practical Example: Auto Repair Shop

Consider a scenario at an auto repair shop:

MCP Application

  • Connecting repair tools (e.g., jack, multimeter, socket wrench).
  • Providing structured interfaces for tool operations.
  • Handling tool calls with specific parameters.

A2A Application

  • Communication between the customer and the mechanic (“My car is making a clicking sound”).
  • Continuous, two-way communication and dynamic planning (“Please send a photo of the left wheel,” “I noticed a fluid leak. How long has this been happening?”).
  • Collaboration between the shop staff and a parts supplier agent.

Protocol Intersection

We recommend applications model A2A Agents as MCP resources (represented by their AgentCard). Frameworks can then use A2A to communicate with users, remote Agents, and other Agents.

Integration Advantages

  1. Functional Complementarity

    • MCP provides standardized tool interfaces.
    • A2A enables agent collaboration communication.
    • Together, they build a complete agent ecosystem.

  2. Deployment Flexibility

    • Both protocols can be combined as needed.
    • Supports gradual integration.
    • Maintains backward compatibility.

  3. Standardization Benefits

    • Reduces development complexity.
    • Improves system interoperability.
    • Accelerates feature iteration.

Best Practices

  1. Clear Boundaries

    • Use MCP for tool calls.
    • Use A2A for agent communication.
    • Avoid functional overlap.

  2. Security Considerations

    • Implement security mechanisms for both protocols separately.
    • Ensure consistency in authentication and authorization.
    • Protect sensitive information transmission.

  3. Performance Optimization

    • Use the features of both protocols appropriately.
    • Avoid unnecessary protocol conversions.
    • Optimize resource utilization.