Playwright MCP

Instructions

Implementation Reference

• src/playwright_mcp/server.py:270-289 (handler)

  Handler for executing the take_screenshot tool: captures screenshot of page or element, encodes to base64, returns as ImageContent.

  elif name == "take_screenshot":
      page = get_active_page(arguments.get("page_id"))
      selector = arguments.get("selector")
      
      if selector:
          screenshot = await page.locator(selector).screenshot()
      else:
          screenshot = await page.screenshot()
      
      # Convert the bytes to base64
      base64_image = base64.b64encode(screenshot).decode('utf-8')
      
      # Return as ImageContent
      return [types.ImageContent(
          type="image",
          image=types.ImageData(
              mime_type="image/png",
              data=base64_image
          )
      )]

• src/playwright_mcp/server.py:144-154 (registration)

  Registration of the take_screenshot tool in the list_tools() response, defining name, description, and input schema.

  types.Tool(
      name="take_screenshot",
      description="Take a screenshot of the current page",
      inputSchema={
          "type": "object",
          "properties": {
              "page_id": {"type": "string"},
              "selector": {"type": "string"},
          },
      },
  ),

• src/playwright_mcp/server.py:147-153 (schema)

  Input schema definition for take_screenshot tool: optional page_id and selector.

  inputSchema={
      "type": "object",
      "properties": {
          "page_id": {"type": "string"},
          "selector": {"type": "string"},
      },
  },

• src/playwright_mcp/server.py:200-210 (helper)

  Helper function used by take_screenshot (and other tools) to retrieve the active Playwright Page instance.

  def get_active_page(page_id: Optional[str] = None) -> Page:
      """Get the active page based on page_id or current default."""
      global current_page_id
      
      if page_id is None:
          page_id = current_page_id
      
      if page_id not in pages:
          raise ValueError(f"Page not found: {page_id}")
      
      return pages[page_id]