Model Context Protocol(MCP)
  1. Concepts
Model Context Protocol(MCP)
  • Get Started
    • Introduction
    • Example Servers
    • Example Clients
    • Quickstart
      • For Server Developers
      • For Client Developers
      • For Claude Desktop Users
  • Tutorials
    • Building MCP with LLMs
    • Debugging
    • Inspector
  • Concepts
    • Core architecture
    • Resources
    • Prompts
    • Tools
    • Sampling
    • Roots
    • Transports
  • Development
    • What's New
    • Roadmap
    • Contributing
  1. Concepts

Transports

Learn about MCP’s communication mechanisms
Transports in the Model Context Protocol (MCP) provide the foundation for communication between clients and servers. A transport handles the underlying mechanics of how messages are sent and received.

Message Format#

MCP uses JSON-RPC 2.0 as its wire format. The transport layer is responsible for converting MCP protocol messages into JSON-RPC format for transmission and converting received JSON-RPC messages back into MCP protocol messages.
There are three types of JSON-RPC messages used:

Requests#

Responses#

Notifications#

Built-in Transport Types#

MCP includes two standard transport implementations:

Standard Input/Output (stdio)#

The stdio transport enables communication through standard input and output streams. This is particularly useful for local integrations and command-line tools.
Use stdio when:
Building command-line tools
Implementing local integrations
Needing simple process communication
Working with shell scripts
TypeScript (Server)

Server-Sent Events (SSE)#

SSE transport enables server-to-client streaming with HTTP POST requests for client-to-server communication.
Use SSE when:
Only server-to-client streaming is needed
Working with restricted networks
Implementing simple updates
TypeScript (Server)

Custom Transports#

MCP makes it easy to implement custom transports for specific needs. Any transport implementation just needs to conform to the Transport interface:
You can implement custom transports for:
Custom network protocols
Specialized communication channels
Integration with existing systems
Performance optimization
TypeScript
Python
Note that while MCP Servers are often implemented with asyncio, we recommend implementing low-level interfaces like transports with anyio for wider compatibility.

Error Handling#

Transport implementations should handle various error scenarios:
1.
Connection errors
2.
Message parsing errors
3.
Protocol errors
4.
Network timeouts
5.
Resource cleanup
Example error handling:
TypeScript
Python
Note that while MCP Servers are often implemented with asyncio, we recommend implementing low-level interfaces like transports with anyio for wider compatibility.

Best Practices#

When implementing or using MCP transport:
1.
Handle connection lifecycle properly
2.
Implement proper error handling
3.
Clean up resources on connection close
4.
Use appropriate timeouts
5.
Validate messages before sending
6.
Log transport events for debugging
7.
Implement reconnection logic when appropriate
8.
Handle backpressure in message queues
9.
Monitor connection health
10.
Implement proper security measures

Security Considerations#

When implementing transport:

Authentication and Authorization#

Implement proper authentication mechanisms
Validate client credentials
Use secure token handling
Implement authorization checks

SecurityData#

Use TLS for network transport
Encrypt sensitive data
Validate message integrity
Implement message size limits
Sanitize input data

Network Security#

Implement rate limiting
Use appropriate timeouts
Handle denial of service scenarios
Monitor for unusual patterns
Implement proper firewall rules

Debugging Transport#

Tips for debugging transport issues:
1.
Enable debug logging
2.
Monitor message flow
3.
Check connection states
4.
Validate message formats
5.
Test error scenarios
6.
Use network analysis tools
7.
Implement health checks
8.
Monitor resource usage
9.
Test edge cases
10.
Use proper error tracking
Modified at 2025-03-12 07:35:45
Previous
Roots
Next
What's New
Built with