Playwright MCP

Instructions

Implementation Reference

• src/tools/screenshot.ts:48-85 (handler)

  The main handler function that executes the browser_take_screenshot tool logic. It takes a screenshot of the page viewport or specified element using Playwright, saves it to a file, generates explanatory code, and returns a base64-encoded image if supported by the client.

  handle: async (context, params) => {
    const tab = context.currentTabOrDie();
    const snapshot = tab.snapshotOrDie();
    const fileType = params.raw ? 'png' : 'jpeg';
    const fileName = await outputFile(context.config, params.filename ?? `page-${new Date().toISOString()}.${fileType}`);
    const options: playwright.PageScreenshotOptions = { type: fileType, quality: fileType === 'png' ? undefined : 50, scale: 'css', path: fileName };
    const isElementScreenshot = params.element && params.ref;
  
    const code = [
      `// Screenshot ${isElementScreenshot ? params.element : 'viewport'} and save it as ${fileName}`,
    ];
  
    const locator = params.ref ? snapshot.refLocator({ element: params.element || '', ref: params.ref }) : null;
  
    if (locator)
      code.push(`await page.${await generateLocator(locator)}.screenshot(${javascript.formatObject(options)});`);
    else
      code.push(`await page.screenshot(${javascript.formatObject(options)});`);
  
    const includeBase64 = context.clientSupportsImages();
    const action = async () => {
      const screenshot = locator ? await locator.screenshot(options) : await tab.page.screenshot(options);
      return {
        content: includeBase64 ? [{
          type: 'image' as 'image',
          data: screenshot.toString('base64'),
          mimeType: fileType === 'png' ? 'image/png' : 'image/jpeg',
        }] : []
      };
    };
  
    return {
      code,
      action,
      captureSnapshot: true,
      waitForNetwork: false,
    };
  }

• src/tools/screenshot.ts:26-46 (schema)

  Input schema validation using Zod for parameters (raw, filename, element, ref) and tool metadata including the name 'browser_take_screenshot', title, and description.

  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.'),
  }).refine(data => {
    return !!data.element === !!data.ref;
  }, {
    message: 'Both element and ref must be provided or neither.',
    path: ['ref', 'element']
  });
  
  const screenshot = defineTool({
    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',
    },

• src/tools/screenshot.ts:88-90 (registration)

  Exports the screenshot tool for aggregation into the main tools list.

  export default [
    screenshot,
  ];

• src/tools.ts:26-50 (registration)

  Imports the screenshot tool module and includes it in the snapshotTools array via spread operator.

  import snapshot from './tools/snapshot.js';
  import tabs from './tools/tabs.js';
  import screenshot from './tools/screenshot.js';
  import testing from './tools/testing.js';
  import vision from './tools/vision.js';
  import wait from './tools/wait.js';
  
  import type { Tool } from './tools/tool.js';
  
  export const snapshotTools: Tool<any>[] = [
    ...common(true),
    ...console,
    ...dialogs(true),
    ...files(true),
    ...install,
    ...keyboard(true),
    ...navigate(true),
    ...network,
    ...pdf,
    ...screenshot,
    ...snapshot,
    ...tabs(true),
    ...testing,
    ...wait(true),
  ];