browser-use MCP server

Instructions

Implementation Reference

• src/mcp_server_browser_use/server.py:75-167 (handler)

  The core handler function for the 'run_browser_agent' tool. It is registered via the @app.tool() decorator (line 75). Configures and initializes a CustomBrowser, CustomAgent, and executes the browser agent task based on input parameters, handling errors and cleanup.

  @app.tool()
  async def run_browser_agent(task: str, add_infos: str = "") -> str:
      """Handle run-browser-agent tool calls."""
      global _global_agent, _global_browser, _global_browser_context, _global_agent_state
  
      try:
          # Clear any previous agent stop signals
          _global_agent_state.clear_stop()
  
          # Get browser configuration
          headless = get_env_bool("BROWSER_HEADLESS", True)
          disable_security = get_env_bool("BROWSER_DISABLE_SECURITY", False)
          window_w = int(os.getenv("BROWSER_WINDOW_WIDTH", "1280"))
          window_h = int(os.getenv("BROWSER_WINDOW_HEIGHT", "720"))
  
          # Get agent configuration
          model_provider = os.getenv("MCP_MODEL_PROVIDER", "openrouter")
          model_name = os.getenv("MCP_MODEL_NAME", "openai/o3-mini-high")
          temperature = float(os.getenv("MCP_TEMPERATURE", "0.7"))
          max_steps = int(os.getenv("MCP_MAX_STEPS", "100"))
          use_vision = get_env_bool("MCP_USE_VISION", True)
          max_actions_per_step = int(os.getenv("MCP_MAX_ACTIONS_PER_STEP", "5"))
          tool_calling_method = os.getenv("MCP_TOOL_CALLING_METHOD", "auto")
  
          # Configure browser window size
          extra_chromium_args = [f"--window-size={window_w},{window_h}"]
  
          # Initialize browser if needed
          if not _global_browser:
              _global_browser = CustomBrowser(
                  config=BrowserConfig(
                      headless=headless,
                      disable_security=disable_security,
                      extra_chromium_args=extra_chromium_args,
                  )
              )
  
          # Initialize browser context if needed
          if not _global_browser_context:
              _global_browser_context = await _global_browser.new_context(
                  config=BrowserContextConfig(
                      trace_path=os.getenv("BROWSER_TRACE_PATH"),
                      save_recording_path=os.getenv("BROWSER_RECORDING_PATH"),
                      no_viewport=False,
                      browser_window_size=BrowserContextWindowSize(
                          width=window_w, height=window_h
                      ),
                  )
              )
  
          # Prepare LLM
          llm = utils.get_llm_model(
              provider=model_provider, model_name=model_name, temperature=temperature
          )
  
          # Create controller and agent
          controller = CustomController()
          _global_agent = CustomAgent(
              task=task,
              add_infos=add_infos,
              use_vision=use_vision,
              llm=llm,
              browser=_global_browser,
              browser_context=_global_browser_context,
              controller=controller,
              system_prompt_class=CustomSystemPrompt,
              agent_prompt_class=CustomAgentMessagePrompt,
              max_actions_per_step=max_actions_per_step,
              agent_state=_global_agent_state,
              tool_calling_method=tool_calling_method,
          )
  
          # Run agent with improved error handling
          try:
              history = await _global_agent.run(max_steps=max_steps)
              final_result = (
                  history.final_result()
                  or f"No final result. Possibly incomplete. {history}"
              )
              return final_result
          except asyncio.CancelledError:
              return "Task was cancelled"
          except Exception as e:
              logging.error(f"Agent run error: {str(e)}\n{traceback.format_exc()}")
              return f"Error during task execution: {str(e)}"
  
      except Exception as e:
          logging.error(f"run-browser-agent error: {str(e)}\n{traceback.format_exc()}")
          return f"Error during task execution: {str(e)}"
  
      finally:
          asyncio.create_task(_safe_cleanup())