Fetch MCP Server

Instructions

Implementation Reference

• src/Fetcher.ts:61-89 (handler)

  The main handler function for 'fetch_txt' tool. Fetches HTML, uses JSDOM to parse, removes scripts and styles, extracts body textContent, normalizes whitespace, and returns as plain text content.

  static async txt(requestPayload: RequestPayload) {
    try {
      const response = await this._fetch(requestPayload);
      const html = await response.text();
  
      const dom = new JSDOM(html);
      const document = dom.window.document;
  
      const scripts = document.getElementsByTagName("script");
      const styles = document.getElementsByTagName("style");
      Array.from(scripts).forEach((script) => script.remove());
      Array.from(styles).forEach((style) => style.remove());
  
      const text = document.body.textContent || "";
  
      const normalizedText = text.replace(/\s+/g, " ").trim();
  
      return {
        content: [{ type: "text", text: normalizedText }],
        isError: false,
      };
    } catch (error) {
      return {
        content: [{ type: "text", text: (error as Error).message }],
        isError: true,
      };
    }
  }

• src/index.ts:118-120 (registration)

  Registration/dispatch logic in CallToolRequest handler that invokes Fetcher.txt for 'fetch_txt' tool.

  if (request.params.name === "fetch_txt") {
    const fetchResult = await Fetcher.txt(validatedArgs);
    return fetchResult;

• src/index.ts:64-82 (schema)

  Tool schema definition including name, description, and inputSchema for 'fetch_txt' registered in ListTools handler.

  {
    name: "fetch_txt",
    description:
      "Fetch a website, return the content as plain text (no HTML)",
    inputSchema: {
      type: "object",
      properties: {
        url: {
          type: "string",
          description: "URL of the website to fetch",
        },
        headers: {
          type: "object",
          description: "Optional headers to include in the request",
        },
      },
      required: ["url"],
    },
  },

• src/types.ts:3-6 (schema)

  Zod schema for request payload (url required, headers optional) used to validate inputs for all fetch tools including 'fetch_txt'.

  export const RequestPayloadSchema = z.object({
    url: z.string().url(),
    headers: z.record(z.string()).optional(),
  });

• src/Fetcher.ts:5-30 (helper)

  Helper function to perform the actual fetch with custom User-Agent and error handling, used by all tool handlers including 'fetch_txt'.

  export class Fetcher {
    private static async _fetch({
      url,
      headers,
    }: RequestPayload): Promise<Response> {
      try {
        const response = await fetch(url, {
          headers: {
            "User-Agent":
              "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/120.0.0.0 Safari/537.36",
            ...headers,
          },
        });
  
        if (!response.ok) {
          throw new Error(`HTTP error: ${response.status}`);
        }
        return response;
      } catch (e: unknown) {
        if (e instanceof Error) {
          throw new Error(`Failed to fetch ${url}: ${e.message}`);
        } else {
          throw new Error(`Failed to fetch ${url}: Unknown error`);
        }
      }
    }