MCP and A2A Dual Protocol RBAC Security: **With Live Demo **

[vishalmysore]

Pre-submission Checklist

• This post follows the MCP community guidelines

What would you like to share?

👋 Hey everyone! I want to share my journey of building a unified RBAC based security implementation that bridges A2A (Agent-to-Agent) and MCP (Model Context Protocol) systems. You can integrate this with Claude Desktop or any MCP client as well as A2A clients.

🌐 Live Demo: https://vishalmysore-a2amcpdemo.hf.space/index.html

What I Built 🏗️

I created a security integration layer that enables:

1. Single agent serving both A2A and MCP protocols
2. Role-based access control using Spring Security
3. Dynamic capability exposure based on user roles
4. Unified security context across protocols

How I Built It 🛠️

1. Core Architecture

   • Built on Spring Boot framework
   • Integrated Spring Security for authentication
   • Implemented A2A protocol handlers
   • Added MCP support for AI model interactions

2. Security Implementation

   @Agent(groupName = "car booking")
   public class CarBookingAgent {
       @PreAuthorize("hasRole('USER')")
       @Action(description = "Book a car")
       public String bookCar(/*...*/) { /*...*/ }
   
       @PreAuthorize("hasRole('ADMIN')")
       @Action(description = "Cancel a booking")
       public String cancelCarBooking(/*...*/) { /*...*/ }
   
       // Public action - no role required
       @Action(description = "Check status")
       public String getBookingStatus(/*...*/) { /*...*/ }
   }

3. Protocol Integration

   • Created protocol-specific adapters
   • Implemented shared authentication handlers
   • Added security context propagation

See It In Action 👀

Here's how it works with our car booking demo:

@Agent(groupName = "car booking")
public class CarBookingAgent {
    @PreAuthorize("hasRole('USER')")
    @Action(description = "Book a car")
    public String bookCar(/*...*/) { /*...*/ }

    @PreAuthorize("hasRole('ADMIN')")
    @Action(description = "Cancel a booking")
    public String cancelCarBooking(/*...*/) { /*...*/ }

    // Public action - no role required
    @Action(description = "Check status")
    public String getBookingStatus(/*...*/) { /*...*/ }
}

Challenges Faced 🎯

1. Protocol Synchronization

   • Challenge: Maintaining consistent security context across A2A and MCP
   • Solution: Implemented a shared security context provider
   • Impact: Seamless security across protocols

2. Authentication Flow

   • Challenge: Different authentication mechanisms for A2A and MCP
   • Solution: Created an abstraction layer for authentication
   • Impact: Unified authentication handling

3. Role-Based Access

   • Challenge: Dynamic capability exposure based on roles
   • Solution: Implemented smart agent card generation
   • Impact: Users see only their allowed actions

4. Client Integration

   • Challenge: Supporting both Python and Java clients
   • Solution: Created protocol-specific adapters
   • Impact: Smooth integration for all clients

Lessons Learned 📚

1. Architecture Insights

   • Spring Security is highly adaptable for custom protocols
   • Protocol-agnostic security design is essential
   • Role-based access control should be decided at design time
   • Caching security context improves performance

2. Best Practices

   • Use annotation-based security consistently
   • Implement security at the protocol level
   • Keep authentication mechanism pluggable
   • Test with different client implementations

3. Integration Lessons

   • Start with clear role definitions
   • Plan for future protocol additions
   • Consider performance implications
   • Document security boundaries clearly

Tips for Others 💡

1. Getting Started

   # Test basic setup with user role
   curl -u user:password https://vishalmysore-a2amcpdemo.hf.space/.well-known/agent.json
   
   # Check admin capabilities
   curl -u admin:admin https://vishalmysore-a2amcpdemo.hf.space/.well-known/agent.json

2. Implementation Tips

   • Start with clear role definitions
   • Use Spring Security's built-in capabilities
   • Test security context persistence
   • Plan for scalability

3. Common Pitfalls to Avoid

   • Don't mix security contexts between protocols
   • Avoid hardcoding roles in business logic
   • Don't expose sensitive data in public endpoints
   • Remember to test with different client types

Real-World Impact 🌍

This implementation solves several common challenges:

1. Cross-Protocol Security

   • No more duplicate security logic
   • Consistent behavior everywhere
   • Simplified maintenance

2. Role Management

   • Clear capability boundaries
   • Easy to add new roles
   • Granular access control

3. Client Integration

   • Clean API for both protocols
   • Predictable behavior
   • Easy to implement

Try It Yourself! 🛠️

Want to see it in action? Check out the full implementation.

What's Next? 🎯

I'm planning to add:

• OAuth2/JWT support
• Enhanced audit logging
• More granular permissions
• Additional protocol bridges

Looking for Feedback! 💭

I'd love to hear:

1. How do you handle security across different protocols?
2. What features would make this more useful for your use case?
3. Any suggestions for improvements?

Let's discuss in the comments!

#A2AJava #MCP #SpringSecurity #AIAgents #SecurityImplementation

Relevant Links

https://github.com/vishalmysore/a2a-mcp-with-security
https://vishalmysore-a2amcpdemo.hf.space/index.html