ext-apps/examples/integration-server/server.ts

import {
  registerAppResource,
  registerAppTool,
  RESOURCE_MIME_TYPE,
} from "@modelcontextprotocol/ext-apps/server";
import { McpServer } from "@modelcontextprotocol/sdk/server/mcp.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import type {
  CallToolResult,
  ReadResourceResult,
} from "@modelcontextprotocol/sdk/types.js";
import fs from "node:fs/promises";
import path from "node:path";
import { z } from "zod";
import { startServer } from "./server-utils.js";

const DIST_DIR = path.join(import.meta.dirname, "dist");
const RESOURCE_URI = "ui://get-time/mcp-app.html";

/**
 * Creates a new MCP server instance with tools and resources registered.
 */
export function createServer(): McpServer {
  const server = new McpServer({
    name: "Integration Test Server",
    version: "1.0.0",
  });

  registerAppTool(
    server,
    "get-time",
    {
      title: "Get Time",
      description: "Returns the current server time.",
      inputSchema: {},
      outputSchema: z.object({
        time: z.string(),
      }),
      _meta: { ui: { resourceUri: RESOURCE_URI } },
    },
    async (): Promise<CallToolResult> => {
      const time = new Date().toISOString();
      return {
        content: [
          {
            type: "text",
            text: JSON.stringify({ time }),
          },
        ],
        structuredContent: { time },
      };
    },
  );

  registerAppResource(
    server,
    RESOURCE_URI,
    RESOURCE_URI,
    { mimeType: RESOURCE_MIME_TYPE },
    async (): Promise<ReadResourceResult> => {
      const html = await fs.readFile(
        path.join(DIST_DIR, "mcp-app.html"),
        "utf-8",
      );
      return {
        contents: [
          { uri: RESOURCE_URI, mimeType: RESOURCE_MIME_TYPE, text: html },
        ],
      };
    },
  );

  return server;
}

async function main() {
  if (process.argv.includes("--stdio")) {
    await createServer().connect(new StdioServerTransport());
  } else {
    const port = parseInt(process.env.PORT ?? "3001", 10);
    await startServer(createServer, { port, name: "Integration Test Server" });
  }
}

main().catch((e) => {
  console.error(e);
  process.exit(1);
});