初学者的模型上下文协议(MCP)课程

发表于 2025-08-12 12:52:05 | 已阅读: 76  次

多模态集成

多模态应用在人工智能中变得越来越重要,能够实现更丰富的交互和更复杂的任务。Model Context Protocol (MCP) 提供了一个构建多模态应用的框架,能够处理各种类型的数据,如文本、图像和音频。

MCP 不仅支持基于文本的交互,还支持多模态功能,使模型能够处理图像、音频及其他数据类型。

介绍

在本课中,你将学习如何构建一个多模态应用。

学习目标

完成本课后,你将能够:

  • 理解多模态的选择
  • 实现一个多模态应用

多模态支持的架构

多模态 MCP 实现通常包括:

  • 特定模态解析器:将不同媒体类型转换为模型可处理格式的组件。
  • 特定模态工具:专门处理特定模态(图像分析、音频处理)的工具。
  • 统一上下文管理:跨不同模态维护上下文的系统。
  • 响应生成:能够生成包含多种模态的响应。

多模态示例:图像分析

下面的示例中,我们将分析一张图像并提取信息。

C# 实现

using ModelContextProtocol.SDK.Server;
using ModelContextProtocol.SDK.Server.Tools;
using ModelContextProtocol.SDK.Server.Content;
using System.Text.Json;
using System.IO;
using System.Threading.Tasks;
using System.Collections.Generic;

namespace MultiModalMcpExample
{
    // Tool for image analysis
    public class ImageAnalysisTool : ITool
    {
        private readonly IImageAnalysisService _imageService;
        
        public ImageAnalysisTool(IImageAnalysisService imageService)
        {
            _imageService = imageService;
        }
        
        public string Name => "imageAnalysis";
        public string Description => "Analyzes image content and extracts information";
          public ToolDefinition GetDefinition()
        {
            return new ToolDefinition
            {
                Name = Name,
                Description = Description,
                Parameters = new Dictionary<string, ParameterDefinition>
                {
                    ["imageUrl"] = new ParameterDefinition
                    {
                        Type = ParameterType.String,
                        Description = "URL to the image to analyze" 
                    },
                    ["analysisType"] = new ParameterDefinition
                    {
                        Type = ParameterType.String,
                        Description = "Type of analysis to perform",
                        Enum = new[] { "general", "objects", "text", "faces" },
                        Default = "general"
                    }
                },
                Required = new[] { "imageUrl" }
            };
        }
        
        public async Task<ToolResponse> ExecuteAsync(IDictionary<string, object> parameters)
        {
            // Extract parameters
            string imageUrl = parameters["imageUrl"].ToString();
            string analysisType = parameters.ContainsKey("analysisType") 
                ? parameters["analysisType"].ToString() 
                : "general";
              // Download or access the image
            byte[] imageData = await DownloadImageAsync(imageUrl);
            
            // Analyze based on the requested analysis type
            var analysisResult = analysisType switch
            {
                "objects" => await _imageService.DetectObjectsAsync(imageData),                "text" => await _imageService.RecognizeTextAsync(imageData),
                "faces" => await _imageService.DetectFacesAsync(imageData),
                _ => await _imageService.AnalyzeGeneralAsync(imageData) // Default general analysis
            };
            
            // Return structured result as a ToolResponse
            // Format follows the MCP specification for content structure
            var content = new List<ContentItem>
            {
                new ContentItem
                {
                    Type = ContentType.Text,
                    Text = JsonSerializer.Serialize(analysisResult)
                }
            };
            
            return new ToolResponse
            {
                Content = content,
                IsError = false
            };
        }
        
        private async Task<byte[]> DownloadImageAsync(string url)
        {
            using var httpClient = new HttpClient();
            return await httpClient.GetByteArrayAsync(url);
        }
    }
    
    // Multi-modal MCP server with image and text processing
    public class MultiModalMcpServer
    {
        public static async Task Main(string[] args)
        {
            // Create an MCP server
            var server = new McpServer(
                name: "Multi-Modal MCP Server",
                version: "1.0.0"
            );
            
            // Configure server for multi-modal support
            var serverOptions = new McpServerOptions
            {
                MaxRequestSize = 10 * 1024 * 1024, // 10MB for larger payloads like images
                SupportedContentTypes = new[]
                {
                    "image/jpeg",
                    "image/png",
                    "text/plain",
                    "application/json"
                }
            };
            
            // Create image analysis service
            var imageService = new ComputerVisionService();
            
            // Register image analysis tools
            server.AddTool(new ImageAnalysisTool(imageService));
            
            // Register a text-to-image tool
            services.AddMcpTool<TextAnalysisTool>();
            services.AddMcpTool<ImageAnalysisTool>();
            services.AddMcpTool<DocumentGenerationTool>(); // Tool that can generate documents with text and images
        }
    }
}

在上述示例中,我们:

  • 创建了一个 ImageAnalysisTool,使用假设的 IImageAnalysisService 来分析图像。
  • 配置了 MCP 服务器以处理更大请求并支持图像内容类型。
  • 将图像分析工具注册到服务器。
  • 实现了一个方法,从 URL 下载图像并根据请求类型(对象、文本、面部等)进行分析。
  • 返回符合 MCP 规范的结构化结果。

多模态示例:音频处理

音频处理是多模态应用中另一种常见的模态。下面是一个实现音频转录工具的示例,该工具可以处理音频文件并返回转录文本。

Java 实现

package com.example.mcp.multimodal;

import com.mcp.server.McpServer;
import com.mcp.tools.Tool;
import com.mcp.tools.ToolRequest;
import com.mcp.tools.ToolResponse;
import com.mcp.tools.ToolExecutionException;
import com.example.audio.AudioProcessor;

import java.util.Base64;
import java.util.HashMap;
import java.util.Map;

// Audio transcription tool
public class AudioTranscriptionTool implements Tool {
    private final AudioProcessor audioProcessor;
    
    public AudioTranscriptionTool(AudioProcessor audioProcessor) {
        this.audioProcessor = audioProcessor;
    }
    
    @Override
    public String getName() {
        return "audioTranscription";
    }
    
    @Override
    public String getDescription() {
        return "Transcribes speech from audio files to text";
    }
    
    @Override
    public Object getSchema() {
        Map<String, Object> schema = new HashMap<>();
        schema.put("type", "object");
        
        Map<String, Object> properties = new HashMap<>();
        
        Map<String, Object> audioUrl = new HashMap<>();
        audioUrl.put("type", "string");
        audioUrl.put("description", "URL to the audio file to transcribe");
        
        Map<String, Object> audioData = new HashMap<>();
        audioData.put("type", "string");
        audioData.put("description", "Base64-encoded audio data (alternative to URL)");
        
        Map<String, Object> language = new HashMap<>();
        language.put("type", "string");
        language.put("description", "Language code (e.g., 'en-US', 'es-ES')");
        language.put("default", "en-US");
        
        properties.put("audioUrl", audioUrl);
        properties.put("audioData", audioData);
        properties.put("language", language);
        
        schema.put("properties", properties);
        schema.put("required", Arrays.asList("audioUrl"));
        
        return schema;
    }
    
    @Override
    public ToolResponse execute(ToolRequest request) {
        try {
            byte[] audioData;
            String language = request.getParameters().has("language") ? 
                request.getParameters().get("language").asText() : "en-US";
                
            // Get audio either from URL or direct data
            if (request.getParameters().has("audioUrl")) {
                String audioUrl = request.getParameters().get("audioUrl").asText();
                audioData = downloadAudio(audioUrl);
            } else if (request.getParameters().has("audioData")) {
                String base64Audio = request.getParameters().get("audioData").asText();
                audioData = Base64.getDecoder().decode(base64Audio);
            } else {
                throw new ToolExecutionException("Either audioUrl or audioData must be provided");
            }
            
            // Process audio and transcribe
            Map<String, Object> transcriptionResult = audioProcessor.transcribe(audioData, language);
            
            // Return transcription result
            return new ToolResponse.Builder()
                .setResult(transcriptionResult)
                .build();
        } catch (Exception ex) {
            throw new ToolExecutionException("Audio transcription failed: " + ex.getMessage(), ex);
        }
    }
    
    private byte[] downloadAudio(String url) {
        // Implementation for downloading audio from URL
        // ...
        return new byte[0]; // Placeholder
    }
}

// Main application with audio and other modalities
public class MultiModalApplication {
    public static void main(String[] args) {
        // Configure services
        AudioProcessor audioProcessor = new AudioProcessor();
        ImageProcessor imageProcessor = new ImageProcessor();
        
        // Create and configure server
        McpServer server = new McpServer.Builder()
            .setName("Multi-Modal MCP Server")
            .setVersion("1.0.0")
            .setPort(5000)
            .setMaxRequestSize(20 * 1024 * 1024) // 20MB for audio/video content
            .build();
            
        // Register multi-modal tools
        server.registerTool(new AudioTranscriptionTool(audioProcessor));
        server.registerTool(new ImageAnalysisTool(imageProcessor));
        server.registerTool(new VideoProcessingTool());
        
        // Start server
        server.start();
        System.out.println("Multi-Modal MCP Server started on port 5000");
    }
}

在上述示例中,我们:

  • 创建了一个 AudioTranscriptionTool,能够转录音频文件。
  • 定义了工具的 schema,接受 URL 或 base64 编码的音频数据。
  • 实现了 execute 方法来处理音频处理和转录。
  • 配置了 MCP 服务器以处理多模态请求,包括音频和图像处理。
  • 将音频转录工具注册到服务器。
  • 实现了一个方法,从 URL 下载音频文件或解码 base64 音频数据。
  • 使用 AudioProcessor 服务来处理实际的转录逻辑。
  • 启动 MCP 服务器以监听请求。

多模态示例:多模态响应生成

Python 实现

from mcp_server import McpServer
from mcp_tools import Tool, ToolRequest, ToolResponse, ToolExecutionException
import base64
from PIL import Image
import io
import requests
import json
from typing import Dict, Any, List, Optional

# Image generation tool
class ImageGenerationTool(Tool):
    def get_name(self):
        return "imageGeneration"
        
    def get_description(self):
        return "Generates images based on text descriptions"
    
    def get_schema(self):
        return {
            "type": "object",
            "properties": {
                "prompt": {
                    "type": "string", 
                    "description": "Text description of the image to generate"
                },
                "style": {
                    "type": "string",
                    "enum": ["realistic", "artistic", "cartoon", "sketch"],
                    "default": "realistic"
                },
                "width": {
                    "type": "integer",
                    "default": 512
                },
                "height": {
                    "type": "integer",
                    "default": 512
                }
            },
            "required": ["prompt"]
        }
    
    async def execute_async(self, request: ToolRequest) -> ToolResponse:
        try:
            # Extract parameters
            prompt = request.parameters.get("prompt")
            style = request.parameters.get("style", "realistic")
            width = request.parameters.get("width", 512)
            height = request.parameters.get("height", 512)
            
            # Generate image using external service (example implementation)
            image_data = await self._generate_image(prompt, style, width, height)
            
            # Convert image to base64 for response
            buffered = io.BytesIO()
            image_data.save(buffered, format="PNG")
            img_str = base64.b64encode(buffered.getvalue()).decode()
            
            # Return result with both the image and metadata
            return ToolResponse(
                result={
                    "imageBase64": img_str,
                    "format": "image/png",
                    "width": width,
                    "height": height,
                    "generationPrompt": prompt,
                    "style": style
                }
            )
        except Exception as e:
            raise ToolExecutionException(f"Image generation failed: {str(e)}")
    
    async def _generate_image(self, prompt: str, style: str, width: int, height: int) -> Image.Image:
        """
        This would call an actual image generation API
        Simplified placeholder implementation
        """
        # Return a placeholder image or call actual image generation API
        # For this example, we'll create a simple colored image
        image = Image.new('RGB', (width, height), color=(73, 109, 137))
        return image

# Multi-modal response handler
class MultiModalResponseHandler:
    """Handler for creating responses that combine text, images, and other modalities"""
    
    def __init__(self, mcp_client):
        self.client = mcp_client
    
    async def create_multi_modal_response(self, 
                                         text_content: str, 
                                         generate_images: bool = False,
                                         image_prompts: Optional[List[str]] = None) -> Dict[str, Any]:
        """
        Creates a response that may include generated images alongside text
        """
        response = {
            "text": text_content,
            "images": []
        }
        
        # Generate images if requested
        if generate_images and image_prompts:
            for prompt in image_prompts:
                image_result = await self.client.execute_tool(
                    "imageGeneration",
                    {
                        "prompt": prompt,
                        "style": "realistic",
                        "width": 512,
                        "height": 512
                    }
                )
                
                response["images"].append({
                    "imageData": image_result.result["imageBase64"],
                    "format": image_result.result["format"],
                    "prompt": prompt
                })
        
        return response

# Main application
async def main():
    # Create server
    server = McpServer(
        name="Multi-Modal MCP Server",
        version="1.0.0",
        port=5000
    )
    
    # Register multi-modal tools
    server.register_tool(ImageGenerationTool())
    server.register_tool(AudioAnalysisTool())
    server.register_tool(VideoFrameExtractionTool())
    
    # Start server
    await server.start()
    print("Multi-Modal MCP Server running on port 5000")

if __name__ == "__main__":
    import asyncio
    asyncio.run(main())

接下来

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