Playwright MCP

Instructions

Implementation Reference

• src/playwright_mcp/server.py:166-176 (registration)

  Registration of the 'switch_page' tool in the list_tools handler, including its schema definition.

  types.Tool(
      name="switch_page",
      description="Switch to a different browser page",
      inputSchema={
          "type": "object",
          "properties": {
              "page_id": {"type": "string"},
          },
          "required": ["page_id"],
      },
  ),

• src/playwright_mcp/server.py:305-315 (handler)

  Handler logic for the 'switch_page' tool: retrieves page_id from arguments, validates existence, updates global current_page_id, and returns confirmation.

  elif name == "switch_page":
      page_id = arguments.get("page_id")
      if not page_id:
          raise ValueError("Page ID is required")
          
      if page_id not in pages:
          raise ValueError(f"Page ID '{page_id}' not found")
          
      current_page_id = page_id
      
      return [types.TextContent(type="text", text=f"Switched to page: {page_id}")]

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

  Helper function get_active_page used by switch_page and other tools to retrieve the active Page object based on page_id or current_page_id.

  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]