MCP Server Fetch TypeScript

Instructions

Implementation Reference

• src/index.ts:68-81 (registration)

  Registers the get_rendered_html tool with its description and input schema (requires 'url').

  {
    name: "get_rendered_html",
    description: "Fetches fully rendered HTML content using a headless browser, including JavaScript-generated content. Essential for modern web applications, single-page applications (SPAs), or any content that requires client-side rendering to be complete.",
    inputSchema: {
      type: "object",
      properties: {
        url: {
          type: "string",
          description: "URL of the target web page that requires JavaScript execution or dynamic content rendering."
        }
      },
      required: ["url"]
    }
  },

• src/index.ts:135-142 (handler)

  Tool handler case in CallToolRequestSchema that fetches rendered HTML via getHtmlString and returns it as text content.

  case "get_rendered_html": {
    return {
      content: [{
        type: "text",
        text: (await getHtmlString(url))
      }]
    };
  }

• src/index.ts:174-210 (handler)

  Executes the tool logic: launches headless Chromium browser with Playwright, navigates to URL, waits for DOM content loaded, retrieves full HTML content, handles errors and cleanup.

  async function getHtmlString(request_url: string): Promise<string> {
    let browser: Browser | null = null;
    let page: Page | null = null;
    try {
      browser = await chromium.launch({
        headless: true,
        // args: ['--single-process'], 
      });
      const context = await browser.newContext();
      page = await context.newPage();
  
      await page.goto(request_url, {
        waitUntil: 'domcontentloaded',
        timeout: TIMEOUT,
      });
      const htmlString = await page.content();
      return htmlString;
    } catch (error) {
      console.error(`Failed to fetch HTML for ${request_url}:`, error);
      return ""; 
    } finally {
      if (page) {
        try {
          await page.close();
        } catch (e) {
          console.error("Error closing page:", e);
        }
      }
      if (browser) {
        try {
          await browser.close();
        } catch (error) {
          console.error('Error closing browser:', error);
        }
      }
    }
  }

• src/index.ts:71-80 (schema)

  Input schema defining the required 'url' parameter as a string.

  inputSchema: {
    type: "object",
    properties: {
      url: {
        type: "string",
        description: "URL of the target web page that requires JavaScript execution or dynamic content rendering."
      }
    },
    required: ["url"]
  }