feat: mcp server sdk (#4794)

Signed-off-by: kevin <wanjunfeng@gmail.com>

mcp/readme.md

@@ -0,0 +1,62 @@
+# 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