MCP 完全指南：从协议原理到 Go 服务开发实战

# 创建项目
mkdir mcp-demo && cd mcp-demo
go mod init mcp-demo

# 安装 mcp-go 库
go get github.com/mark3labs/mcp-go@v0.45.0

package main

import (
	"context"
	"flag"
	"fmt"
	"log"
	"os"

	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"
)

func main() {
	transport := flag.String("t", "stdio", "传输模式: stdio, http")
	port := flag.Int("port", 8080, "HTTP 模式端口")
	flag.Parse()

	s := server.NewMCPServer(
		"go-demo-server",
		"1.0.0",
		server.WithResourceCapabilities(true, true),
		server.WithToolCapabilities(true),
		server.WithLogging(),
	)

	registerTools(s)

	if *transport == "http" {
		log.Printf("启动 HTTP 模式，端口 %d", *port)
		httpServer := server.NewStreamableHTTPServer(s)
		httpServer.Start(fmt.Sprintf(":%d", *port))
	} else {
		log.Println("启动 stdio 模式")
		server.ServeStdio(s)
	}
}

func registerTools(s *server.MCPServer) {
	// echo 工具
	s.AddTool(
		mcp.NewTool("echo",
			mcp.WithDescription("返回输入的文本"),
			mcp.WithString("text",
				mcp.Description("要回显的文本"),
				mcp.Required(),
			),
		),
		func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
			args := request.GetArguments()
			text := args["text"].(string)
			return &mcp.CallToolResult{
				Content: []mcp.Content{
					mcp.NewTextContent(fmt.Sprintf("Echo: %s", text)),
				},
			}, nil
		},
	)

	// add 工具
	s.AddTool(
		mcp.NewTool("add",
			mcp.WithDescription("计算两个数的和"),
			mcp.WithNumber("a", mcp.Description("第一个数"), mcp.Required()),
			mcp.WithNumber("b", mcp.Description("第二个数"), mcp.Required()),
		),
		func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
			args := request.GetArguments()
			a := args["a"].(float64)
			b := args["b"].(float64)
			return &mcp.CallToolResult{
				Content: []mcp.Content{
					mcp.NewTextContent(fmt.Sprintf("%d + %d = %d", int64(a), int64(b), int64(a+b))),
				},
			}, nil
		},
	)

	// get_weather 工具
	s.AddTool(
		mcp.NewTool("get_weather",
			mcp.WithDescription("获取指定城市的天气"),
			mcp.WithString("location",
				mcp.Description("城市名称"),
				mcp.Required(),
			),
		),
		func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
			args := request.GetArguments()
			location := args["location"].(string)
			weather := map[string]string{
				"beijing":  "☀️ 晴天, 15°C",
				"shanghai": "🌧️ 小雨, 18°C",
				"shenzhen": "☀️ 晴天, 24°C",
			}
			desc := weather[location]
			if desc == "" {
				desc = "🌤️ 多云"
			}
			return &mcp.CallToolResult{
				Content: []mcp.Content{
					mcp.NewTextContent(fmt.Sprintf("%s: %s", location, desc)),
				},
			}, nil
		},
	)
}

# 编译
go build -o mcp-server main.go

# stdio 模式 (本地)
./mcp-server

# HTTP 模式 (远程)
./mcp-server -t http -port 8080

# 添加 MCP 服务
mcporter config add go-demo \
  --url "http://localhost:8080/mcp" \
  --type http

# 查看工具列表
mcporter list go-demo

# 调用工具
mcporter call "go-demo.add(a: 5, b: 3)"

// ~/.openclaw/workspace/config/mcporter.json
{
  "mcpServers": {
    "go-demo": {
      "baseUrl": "http://localhost:8080/mcp"
    }
  }
}