go-zero/mcp

Model Context Protocol (MCP) SDK Implementation

Overview

This package implements a Model Context Protocol (MCP) server in Go that facilitates real-time communication between AI models and clients using Server-Sent Events (SSE). The implementation provides a framework for building AI-assisted applications with bidirectional communication capabilities.

Core Components

Server-Sent Events (SSE) Communication

• Real-time Communication: Robust SSE-based communication system that maintains persistent connections with clients
• Connection Management: Client registration, message broadcasting, and client cleanup mechanisms
• Event Handling: Event types for tools, prompts, and resources changes

JSON-RPC Implementation

• Request Processing: Complete JSON-RPC request processor for handling MCP protocol methods
• Response Formatting: Proper response formatting according to JSON-RPC specifications
• Error Handling: Comprehensive error handling with appropriate error codes

Tool Management

• Tool Registration: System to register custom tools with handlers
• Tool Execution: Mechanism to execute tool functions with proper timeout handling
• Result Handling: Flexible result handling supporting various return types (string, JSON, images)

Prompt System

• Prompt Registration: System for registering both static and dynamic prompts
• Argument Validation: Validation for required arguments and default values for optional ones
• Message Generation: Handlers that generate properly formatted conversation messages

Resource Management

• Resource Registration: System for managing and accessing external resources
• Content Delivery: Handlers for delivering resource content to clients on demand
• Resource Subscription: Mechanisms for clients to subscribe to resource updates

Protocol Features

• Initialization Sequence: Proper handshaking with capability negotiation
• Notification Handling: Support for both standard and client-specific notifications
• Message Routing: Intelligent routing of requests to appropriate handlers

Technical Highlights

Configuration System

• Flexible Configuration: Configuration system with sensible defaults and customization options
• CORS Support: Configurable CORS settings for cross-origin requests
• Server Information: Proper server identification and versioning

Client Session Management

• Session Tracking: Client session tracking with unique identifiers
• Connection Health: Ping/pong mechanism to maintain connection health
• Initialization State: Client initialization state tracking

Content Handling

• Multi-format Content: Support for text, code, and binary content
• MIME Type Support: Proper MIME type identification for various content types
• Audience Annotations: Content audience annotations for user/assistant targeting

Usage

To create and use an MCP server, see the examples directory for practical implementation examples including:

• Tool registration and execution
• Static and dynamic prompt creation
• Resource handling with proper URI identification
• Embedded resources in prompt responses
• Client connection management