go

switch method {
case "initialize":
    sendResponse(id, ...)  // ✅ 必须响应
    
case "tools/list":  
    sendResponse(id, ...)  // ✅ 必须响应
    
case "tools/call":
    sendResponse(id, ...)  // ✅ 有工具时必需
    
default:
    // 对于 notifications/initialized 或其他未知方法
    // 什么都不做即可，不需要报错
    // 因为通知本来就不期待响应
}

json

{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "initialize",
  "params": {
    "protocolVersion": "0.1.0",
    "capabilities": {},
    "clientInfo": {
      "name": "Claude Desktop",
      "version": "1.0.0"
    }
  }
}

json

{
  "jsonrpc": "2.0",
  "id": 1,
  "result": {
    "protocolVersion": "0.1.0",
    "capabilities": {
      "tools": {}
    },
    "serverInfo": {
      "name": "my-server",
      "version": "1.0.0"
    }
  }
}

json

{
  "jsonrpc": "2.0",
  "id": 2,
  "method": "tools/list"
}

json

{
  "jsonrpc": "2.0",
  "id": 2,
  "result": {
    "tools": [
      {
        "name": "say_hello",
        "description": "打招呼用",
        "inputSchema": {
          "type": "object",
          "properties": {}
        }
      }
    ]
  }
}

json

{
  "jsonrpc": "2.0",
  "id": 123,
  "method": "tools/call",
  "params": {
    "name": "to_upper",
    "arguments": {
      "text": "hello world"
    }
  }
}

json

{
  "jsonrpc": "2.0",
  "id": 123,
  "result": {
    "content": [
      {
        "type": "text",
        "text": "HELLO WORLD"
      }
    ],
    "isError": false
  }
}

json

{
  "jsonrpc": "2.0",
  "id": 123,
  "error": {
    "code": -32601,
    "message": "Tool not found: unknown_tool"
  }
}

go

// toupper_mcp.go
package main

import (
	"bufio"
	"encoding/json"
	"fmt"
	"os"
	"strings"
)

func main() {
	scanner := bufio.NewScanner(os.Stdin)

	for scanner.Scan() {
		line := scanner.Text()
		if line == "" {
			continue
		}

		var req map[string]interface{}
		if err := json.Unmarshal([]byte(line), &req); err != nil {
			fmt.Fprintf(os.Stderr, "解析错误: %v\n", err)
			continue
		}

		id, _ := req["id"].(float64)
		method, _ := req["method"].(string)

		switch method {
		case "initialize":
			sendResponse(id, map[string]interface{}{
				"protocolVersion": "2025-03-26",
				"capabilities": map[string]interface{}{
					"tools": map[string]interface{}{}, // 声明支持 tools 能力
				},
				"serverInfo": map[string]string{
					"name":    "toupper-mcp",
					"version": "1.0.0",
				},
			})

		case "tools/list":
			sendResponse(id, map[string]interface{}{
				"tools": []map[string]interface{}{
					{
						"name":        "to_upper",
						"description": "将输入的文本转换为大写",
						"inputSchema": map[string]interface{}{
							"type": "object",
							"properties": map[string]interface{}{
								"text": map[string]string{
									"type":        "string",
									"description": "要转换的文本",
								},
							},
							"required": []string{"text"},
						},
					},
				},
			})

		case "tools/call":
			// 解析工具名称和参数
			params, ok := req["params"].(map[string]interface{})
			if !ok {
				sendError(id, -32602, "Invalid params")
				continue
			}

			toolName, _ := params["name"].(string)
			arguments, _ := params["arguments"].(map[string]interface{})

			if toolName == "to_upper" {
				text, _ := arguments["text"].(string)
				result := strings.ToUpper(text)

				sendResponse(id, map[string]interface{}{
					"content": []map[string]string{
						{
							"type": "text",
							"text": result,
						},
					},
				})
			} else {
				sendError(id, -32601, "Tool not found: "+toolName)
			}

		default:
			// notifications/initialized 或其他方法，忽略即可
			continue
		}
	}
}

func sendResponse(id float64, result interface{}) {
	resp := map[string]interface{}{
		"jsonrpc": "2.0",
		"id":      id,
		"result":  result,
	}
	data, _ := json.Marshal(resp)
	fmt.Println(string(data))
}

func sendError(id float64, code int, message string) {
	resp := map[string]interface{}{
		"jsonrpc": "2.0",
		"id":      id,
		"error": map[string]interface{}{
			"code":    code,
			"message": message,
		},
	}
	data, _ := json.Marshal(resp)
	fmt.Println(string(data))
}

shell

{"jsonrpc":"2.0","id":1,"method":"initialize","params":{}}

{"jsonrpc":"2.0","id":1,"method":"tools/list","params":{}}

{"jsonrpc":"2.0","id":1,"method":"tools/call","params":{"name":"to_upper","arguments":{"text":"hello"}}}

shell

 go build -o toupper_mcp.exe toupper_mcp.go

shell

# 一行命令启动
npx @modelcontextprotocol/inspector your-mcp-server

# 如果是 Go 编译的
npx @modelcontextprotocol/inspector ./your-mcp-server

# 如果是 Python 脚本
npx @modelcontextprotocol/inspector python your_mcp_server.py


# 你也可以用命令行参数直接指定 URL，让 Inspector 启动时自动连接
npx @modelcontextprotocol/inspector --url https://your-server.com/mcp

shell

npx @modelcontextprotocol/inspector -- ./toupper_mcp.exe   
 
npx @modelcontextprotocol/inspector -- "E:\go_ws\demo\toupper_mcp.exe"

json

{
  "mcpServers": {
   "toupper": {
      "command": "E:\\go_ws\\demo\\toupper_mcp.exe",
      "args": []
    }
  }
}