mcp

MCP Tool

A MCP Tool implementation for Eino that implements the Tool interface. This enables seamless integration with Eino's LLM capabilities for enhanced natural language processing and generation.

Features

• Implements github.com/cloudwego/eino/components/tool.BaseTool
• Easy integration with Eino's tool system
• Support for get&call mcp tools

Installation

go get github.com/cloudwego/eino-ext/components/tool/mcp@latest

Quick Start

Here's a quick example of how to use the mcp tool:

package main

import (
	"context"
	"fmt"
	"log"
	"time"

	"github.com/cloudwego/eino/components/tool"
	"github.com/mark3labs/mcp-go/client"
	"github.com/mark3labs/mcp-go/mcp"
	"github.com/mark3labs/mcp-go/server"

	mcpp "github.com/cloudwego/eino-ext/components/tool/mcp"
)

func main() {
	startMCPServer()
	time.Sleep(1 * time.Second)
	ctx := context.Background()

	mcpTools := getMCPTool(ctx)

	for i, mcpTool := range mcpTools {
		fmt.Println(i, ":")
		info, err := mcpTool.Info(ctx)
		if err != nil {
			log.Fatal(err)
		}
		fmt.Println("Name:", info.Name)
		fmt.Println("Desc:", info.Desc)
		fmt.Println()
	}
}

func getMCPTool(ctx context.Context) []tool.BaseTool {
	cli, err := client.NewSSEMCPClient("http://localhost:12345/sse")
	if err != nil {
		log.Fatal(err)
	}
	err = cli.Start(ctx)
	if err != nil {
		log.Fatal(err)
	}

	initRequest := mcp.InitializeRequest{}
	initRequest.Params.ProtocolVersion = mcp.LATEST_PROTOCOL_VERSION
	initRequest.Params.ClientInfo = mcp.Implementation{
		Name:    "example-client",
		Version: "1.0.0",
	}

	_, err = cli.Initialize(ctx, initRequest)
	if err != nil {
		log.Fatal(err)
	}

	tools, err := mcpp.GetTools(ctx, &mcpp.Config{Cli: cli})
	if err != nil {
		log.Fatal(err)
	}

	return tools
}

func startMCPServer() {
	svr := server.NewMCPServer("demo", mcp.LATEST_PROTOCOL_VERSION)
	svr.AddTool(mcp.NewTool("calculate",
		mcp.WithDescription("Perform basic arithmetic operations"),
		mcp.WithString("operation",
			mcp.Required(),
			mcp.Description("The operation to perform (add, subtract, multiply, divide)"),
			mcp.Enum("add", "subtract", "multiply", "divide"),
		),
		mcp.WithNumber("x",
			mcp.Required(),
			mcp.Description("First number"),
		),
		mcp.WithNumber("y",
			mcp.Required(),
			mcp.Description("Second number"),
		),
	), func(ctx context.Context, request mcp.CallToolRequest) (*mcp.CallToolResult, error) {
		op := request.Params.Arguments["operation"].(string)
		x := request.Params.Arguments["x"].(float64)
		y := request.Params.Arguments["y"].(float64)

		var result float64
		switch op {
		case "add":
			result = x + y
		case "subtract":
			result = x - y
		case "multiply":
			result = x * y
		case "divide":
			if y == 0 {
				return mcp.NewToolResultText("Cannot divide by zero"), nil
			}
			result = x / y
		}
		log.Printf("Calculated result: %.2f", result)
		return mcp.NewToolResultText(fmt.Sprintf("%.2f", result)), nil
	})
	go func() {
		defer func() {
			e := recover()
			if e != nil {
				fmt.Println(e)
			}
		}()

		err := server.NewSSEServer(svr, server.WithBaseURL("http://localhost:12345")).Start("localhost:12345")

		if err != nil {
			log.Fatal(err)
		}
	}()
}

Configuration

The tool can be configured using the mcp.Config struct:

type Config struct {
    // Cli is the MCP (Model Control Protocol) client, ref: https://github.com/mark3labs/mcp-go?tab=readme-ov-file#tools
    // Notice: should Initialize with server before use
    Cli client.MCPClient
	// ToolNameList specifies which tools to fetch from MCP server
	// If empty, all available tools will be fetched
	ToolNameList []string
}

Examples

See the examples directory for complete usage examples.

For More Details

• Eino Documentation
• MCP Documentation
• MCP SDK Documentation