Playwright MCP

Instructions

Implementation Reference

• src/tools/screenshot.ts:54-83 (handler)

  The handler function for the browser_take_screenshot tool. It captures a screenshot of the viewport, full page, or specified element using Playwright, saves it to a file, adds code and result messages, and returns the image buffer.

  handle: async (tab, params, response) => {
    const fileType = params.raw ? 'png' : 'jpeg';
    const fileName = await outputFile(tab.context.config, params.filename ?? `page-${new Date().toISOString()}.${fileType}`);
    const options: playwright.PageScreenshotOptions = {
      type: fileType,
      quality: fileType === 'png' ? undefined : 50,
      scale: 'css',
      path: fileName,
      ...(params.fullPage !== undefined && { fullPage: params.fullPage })
    };
    const isElementScreenshot = params.element && params.ref;
  
    const screenshotTarget = isElementScreenshot ? params.element : (params.fullPage ? 'full page' : 'viewport');
    response.addCode(`// Screenshot ${screenshotTarget} and save it as ${fileName}`);
  
    // Only get snapshot when element screenshot is needed
    const locator = params.ref ? await tab.refLocator({ element: params.element || '', ref: params.ref }) : null;
  
    if (locator)
      response.addCode(`await page.${await generateLocator(locator)}.screenshot(${javascript.formatObject(options)});`);
    else
      response.addCode(`await page.screenshot(${javascript.formatObject(options)});`);
  
    const buffer = locator ? await locator.screenshot(options) : await tab.page.screenshot(options);
    response.addResult(`Took the ${screenshotTarget} screenshot and saved it as ${fileName}`);
    response.addImage({
      contentType: fileType === 'png' ? 'image/png' : 'image/jpeg',
      data: buffer
    });
  }

• src/tools/screenshot.ts:26-42 (schema)

  Zod schema defining the input parameters for browser_take_screenshot: raw, filename, element, ref, fullPage with validation rules.

  const screenshotSchema = z.object({
    raw: z.boolean().optional().describe('Whether to return without compression (in PNG format). Default is false, which returns a JPEG image.'),
    filename: z.string().optional().describe('File name to save the screenshot to. Defaults to `page-{timestamp}.{png|jpeg}` if not specified.'),
    element: z.string().optional().describe('Human-readable element description used to obtain permission to screenshot the element. If not provided, the screenshot will be taken of viewport. If element is provided, ref must be provided too.'),
    ref: z.string().optional().describe('Exact target element reference from the page snapshot. If not provided, the screenshot will be taken of viewport. If ref is provided, element must be provided too.'),
    fullPage: z.boolean().optional().describe('When true, takes a screenshot of the full scrollable page, instead of the currently visible viewport. Cannot be used with element screenshots.'),
  }).refine(data => {
    return !!data.element === !!data.ref;
  }, {
    message: 'Both element and ref must be provided or neither.',
    path: ['ref', 'element']
  }).refine(data => {
    return !(data.fullPage && (data.element || data.ref));
  }, {
    message: 'fullPage cannot be used with element screenshots.',
    path: ['fullPage']
  });

• src/tools/screenshot.ts:44-84 (registration)

  Registers the browser_take_screenshot tool using defineTabTool, including name, title, description, input schema, and handler reference.

  const screenshot = defineTabTool({
    capability: 'core',
    schema: {
      name: 'browser_take_screenshot',
      title: 'Take a screenshot',
      description: `Take a screenshot of the current page. You can't perform actions based on the screenshot, use browser_snapshot for actions.`,
      inputSchema: screenshotSchema,
      type: 'readOnly',
    },
  
    handle: async (tab, params, response) => {
      const fileType = params.raw ? 'png' : 'jpeg';
      const fileName = await outputFile(tab.context.config, params.filename ?? `page-${new Date().toISOString()}.${fileType}`);
      const options: playwright.PageScreenshotOptions = {
        type: fileType,
        quality: fileType === 'png' ? undefined : 50,
        scale: 'css',
        path: fileName,
        ...(params.fullPage !== undefined && { fullPage: params.fullPage })
      };
      const isElementScreenshot = params.element && params.ref;
  
      const screenshotTarget = isElementScreenshot ? params.element : (params.fullPage ? 'full page' : 'viewport');
      response.addCode(`// Screenshot ${screenshotTarget} and save it as ${fileName}`);
  
      // Only get snapshot when element screenshot is needed
      const locator = params.ref ? await tab.refLocator({ element: params.element || '', ref: params.ref }) : null;
  
      if (locator)
        response.addCode(`await page.${await generateLocator(locator)}.screenshot(${javascript.formatObject(options)});`);
      else
        response.addCode(`await page.screenshot(${javascript.formatObject(options)});`);
  
      const buffer = locator ? await locator.screenshot(options) : await tab.page.screenshot(options);
      response.addResult(`Took the ${screenshotTarget} screenshot and saved it as ${fileName}`);
      response.addImage({
        contentType: fileType === 'png' ? 'image/png' : 'image/jpeg',
        data: buffer
      });
    }
  });