servers/src/duckduckgo/index.ts

#!/usr/bin/env node

import { Server } from "@modelcontextprotocol/sdk/server/index.js";
import { StdioServerTransport } from "@modelcontextprotocol/sdk/server/stdio.js";
import {
  CallToolRequestSchema,
  ListResourcesRequestSchema,
  ListToolsRequestSchema,
  ReadResourceRequestSchema,
  Tool,
} from "@modelcontextprotocol/sdk/types.js";
import fetch from "node-fetch";
import { JSDOM } from "jsdom";

const SEARCH_TOOL: Tool = {
  name: "duckduckgo_search",
  description:
    "Performs a search using DuckDuckGo and returns the top search results. " +
    "Returns titles, snippets, and URLs of the search results. " +
    "Use this tool to search for current information on the internet.",
  inputSchema: {
    type: "object",
    properties: {
      query: {
        type: "string",
        description: "The search query to look up",
      },
      numResults: {
        type: "number",
        description: "Number of results to return (default: 10)",
        default: 10,
      },
    },
    required: ["query"],
  },
};

const server = new Server(
  {
    name: "example-servers/duckduckgo",
    version: "0.1.0",
  },
  {
    capabilities: {
      tools: {},
      resources: {},
    },
  },
);

server.setRequestHandler(ListResourcesRequestSchema, async () => ({
  resources: [
    {
      uri: "duckduckgo://search",
      mimeType: "text/plain",
      name: "DuckDuckGo Search Results",
    },
  ],
}));

server.setRequestHandler(ReadResourceRequestSchema, async (request) => {
  if (request.params.uri.toString() === "duckduckgo://search") {
    return {
      contents: [
        {
          uri: "duckduckgo://search",
          mimeType: "text/plain",
          text: "DuckDuckGo search interface",
        },
      ],
    };
  }
  throw new Error("Resource not found");
});

server.setRequestHandler(ListToolsRequestSchema, async () => ({
  tools: [SEARCH_TOOL],
}));

async function performSearch(query: string, numResults: number = 10) {
  const url = `https://html.duckduckgo.com/html/?q=${encodeURIComponent(query)}`;
  const headers = {
    "User-Agent":
      "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.124 Safari/537.36",
  };

  const response = await fetch(url, { headers });
  if (!response.ok) {
    throw new Error(`HTTP error! status: ${response.status}`);
  }

  const html = await response.text();
  const dom = new JSDOM(html);
  const document = dom.window.document;

  const results = [];
  const resultElements = document.querySelectorAll(".result");

  for (let i = 0; i < Math.min(numResults, resultElements.length); i++) {
    const result = resultElements[i];
    const titleElem = result.querySelector(".result__title");
    const snippetElem = result.querySelector(".result__snippet");
    const urlElem = result.querySelector(".result__url");

    if (titleElem && snippetElem) {
      results.push({
        title: titleElem.textContent?.trim() || "",
        snippet: snippetElem.textContent?.trim() || "",
        url: urlElem?.getAttribute("href") || "",
      });
    }
  }

  return results;
}

server.setRequestHandler(CallToolRequestSchema, async (request) => {
  if (request.params.name === "duckduckgo_search") {
    try {
      const { query, numResults = 10 } = request.params.arguments as {
        query: string;
        numResults?: number;
      };

      const results = await performSearch(query, numResults);
      
      const formattedResults = results
        .map(
          (result) =>
            `Title: ${result.title}\nSnippet: ${result.snippet}\nURL: ${result.url}\n`,
        )
        .join("\n");

      return {
        content: [
          {
            type: "text",
            text: formattedResults || "No results found.",
          },
        ],
        isError: false,
      };
    } catch (error) {
      return {
        content: [
          {
            type: "text",
            text: `Error performing search: ${error instanceof Error ? error.message : String(error)}`,
          },
        ],
        isError: true,
      };
    }
  }

  return {
    content: [
      {
        type: "text",
        text: `Unknown tool: ${request.params.name}`,
      },
    ],
    isError: true,
  };
});

async function runServer() {
  const transport = new StdioServerTransport();
  await server.connect(transport);
  console.error("DuckDuckGo MCP Server running on stdio");
}

runServer().catch((error) => {
  console.error("Fatal error running server:", error);
  process.exit(1);
});