mcp-hello-world/build/server.js

A simple Hello World MCP server

import { McpServer, ResourceTemplate, } from "@modelcontextprotocol/sdk/server/mcp.js";
import { z } from "zod";
/**
 * Creates and configures a Hello World MCP server
 * with one resource, one prompt, and one tool
 */
export function createServer() {
    // Create an MCP server
    const server = new McpServer({
        name: "hello-world",
        version: "1.0.0",
        // Debug handler for incoming method calls
        debug: true,
    });
    // Add a static resource
    server.resource("hello", "hello://world", async (uri) => ({
        contents: [
            {
                uri: uri.href,
                text: "Hello, World from the resource!",
            },
        ],
    }));
    // Add a dynamic resource with parameters
    server.resource("greeting", new ResourceTemplate("greeting://{name}", { list: undefined }), async (uri, { name }) => ({
        contents: [
            {
                uri: uri.href,
                text: `Hello, ${name} from the resource!`,
            },
        ],
    }));
    // Add a prompt
    server.prompt("helpful-assistant", "A helpful assistant prompt", // Add description as second parameter
    () => ({
        messages: [
            {
                role: "assistant",
                content: {
                    type: "text",
                    text: "You are a helpful assistant.",
                },
            },
        ],
    }));
    // Add an echo tool
    server.tool("echo", "Echoes back a message with 'Hello' prefix", { message: z.string().describe("The message to echo") }, async ({ message }) => ({
        content: [
            {
                type: "text",
                text: `You said: ${message}`,
            },
        ],
    }));
    // Add a debug tool to list available tools
    server.tool("debug", "Lists all available tools and methods", {}, async () => ({
        content: [
            {
                type: "text",
                text: JSON.stringify({
                    tools: Object.keys(server),
                    methods: ["tools/invoke", "mcp/capabilities", "debug/info"]
                }, null, 2),
            },
        ],
    }));
    server.tool('add', 'Adds two numbers', {
        a: z.number().describe('The first number'),
        b: z.number().describe('The second number'),
    }, async ({ a, b }) => {
        console.log(`[Mock SDK Server] Executing add tool with a=${a}, b=${b}`);
        const sum = a + b;
        return {
            content: [
                {
                    text: `The sum is: ${sum}`,
                    type: 'text',
                },
            ],
        };
    });
    return server;
}