fetch_url

Instructions

Implementation Reference

• src/tools/fetchUrl.ts:75-137 (handler)

  Implementation of the fetch_url tool: validates URL, sets options, creates browser service and content processor, navigates to URL stealthily, extracts content, and returns it in MCP format.

  export async function fetchUrl(args: any) {
    const url = String(args?.url || "");
    if (!url) {
      logger.error(`URL parameter missing`);
      throw new Error("URL parameter is required");
    }
  
    // Validate URL protocol for security (only allow HTTP and HTTPS)
    validateUrlProtocol(url);
  
    const options: FetchOptions = {
      timeout: Number(args?.timeout) || 30000,
      waitUntil: String(args?.waitUntil || "load") as
        | "load"
        | "domcontentloaded"
        | "networkidle"
        | "commit",
      extractContent: args?.extractContent !== false,
      maxLength: Number(args?.maxLength) || 0,
      returnHtml: args?.returnHtml === true,
      waitForNavigation: args?.waitForNavigation === true,
      navigationTimeout: Number(args?.navigationTimeout) || 10000,
      disableMedia: args?.disableMedia !== false,
      debug: args?.debug,
    };
  
    // Create browser service
    const browserService = new BrowserService(options);
  
    // Create content processor
    const processor = new WebContentProcessor(options, "[FetchURL]");
    let browser: Browser | null = null;
    let page: Page | null = null;
  
    if (browserService.isInDebugMode()) {
      logger.debug(`Debug mode enabled for URL: ${url}`);
    }
  
    try {
      // Create a stealth browser with anti-detection measures
      browser = await browserService.createBrowser();
  
      // Create a stealth browser context
      const { context, viewport } = await browserService.createContext(browser);
  
      // Create a new page with human-like behavior
      page = await browserService.createPage(context, viewport);
  
      // Process page content
      const result = await processor.processPageContent(page, url);
  
      return {
        content: [{ type: "text", text: result.content }],
      };
    } finally {
      // Clean up resources
      await browserService.cleanup(browser, page);
  
      if (browserService.isInDebugMode()) {
        logger.debug(`Browser and page kept open for debugging. URL: ${url}`);
      }
    }
  }

• src/tools/fetchUrl.ts:11-70 (schema)

  Tool definition for fetch_url including name, description, and detailed input schema.

  export const fetchUrlTool = {
    name: "fetch_url",
    description: "Retrieve web page content from a specified URL",
    inputSchema: {
      type: "object",
      properties: {
        url: {
          type: "string",
          description:
            "URL to fetch. Make sure to include the schema (http:// or https:// if not defined, preferring https for most cases)",
        },
        timeout: {
          type: "number",
          description:
            "Page loading timeout in milliseconds, default is 30000 (30 seconds)",
        },
        waitUntil: {
          type: "string",
          description:
            "Specifies when navigation is considered complete, options: 'load', 'domcontentloaded', 'networkidle', 'commit', default is 'load'",
        },
        extractContent: {
          type: "boolean",
          description:
            "Whether to intelligently extract the main content, default is true",
        },
        maxLength: {
          type: "number",
          description:
            "Maximum length of returned content (in characters), default is no limit",
        },
        returnHtml: {
          type: "boolean",
          description:
            "Whether to return HTML content instead of Markdown, default is false",
        },
        waitForNavigation: {
          type: "boolean",
          description:
            "Whether to wait for additional navigation after initial page load (useful for sites with anti-bot verification), default is false",
        },
        navigationTimeout: {
          type: "number",
          description:
            "Maximum time to wait for additional navigation in milliseconds, default is 10000 (10 seconds)",
        },
        disableMedia: {
          type: "boolean",
          description:
            "Whether to disable media resources (images, stylesheets, fonts, media), default is true",
        },
        debug: {
          type: "boolean",
          description:
            "Whether to enable debug mode (showing browser window), overrides the --debug command line flag if specified",
        },
      },
      required: ["url"],
    },
  };

• src/tools/index.ts:5-17 (registration)

  Registration of the fetch_url tool: included in tools array and mapped from name to handler in toolHandlers object.

  // Export tool definitions
  export const tools = [
    fetchUrlTool,
    fetchUrlsTool,
    browserInstallTool
  ];
  
  // Export tool implementations
  export const toolHandlers = {
    [fetchUrlTool.name]: fetchUrl,
    [fetchUrlsTool.name]: fetchUrls,
    [browserInstallTool.name]: browserInstall
  };