利用Playwright MCP与LLM构建复杂的工作流与AI智能体

在当今快速发展的AI领域，将大型语言模型(LLM)与实际应用场景相结合已成为提升生产力的关键。然而，LLM本身存在局限性——它们无法直接与现实世界交互、操作应用程序或执行复杂的工作流。这就是为什么我们需要像Playwright MCP这样的工具来弥合这一差距。

本文将深入探讨如何利用Playwright MCP（Model Context Protocol）与LLM协同工作，构建能够处理复杂任务的工作流和智能AI代理。

什么是Playwright MCP？
Playwright MCP是一个基于Model Context Protocol的桥接工具，它将强大的浏览器自动化框架Playwright与LLM连接起来。MCP协议允许LLM访问外部工具和资源，而Playwright则提供了跨浏览器的自动化能力。

核心组件
Playwright: Microsoft开发的跨浏览器自动化工具，支持Chromium、Firefox和WebKit
MCP Server: 处理LLM与Playwright之间的通信
LLM接口: 提供自然语言理解和任务规划能力
环境设置与安装
prerequisites
Node.js 16+
Python 3.8+
访问LLM API（如OpenAI GPT、Claude等）
安装步骤

安装Playwright

npm install playwright
npx playwright install

安装MCP相关依赖

pip install mcp-client playwright-async

克隆Playwright MCP仓库

git clone https://github.com/your-repo/playwright-mcp.git
cd playwright-mcp
基础配置

config.py

import os
from mcp import ClientSession, StdioServerParameters
from mcp.client.stdio import stdio_client

class PlaywrightMCPConfig:
def init(self):
self.browser_type = "chromium"# chromium, firefox, webkit
self.headless = False
self.timeout = 30000
self.llm_api_key = os.getenv("LLM_API_KEY")

def get_server_params(self):
    return StdioServerParameters(
        command="node",
        args=["path/to/playwright-mcp-server.js"]
    )

构建基础工作流

1. 初始化连接
   import asyncio
   from mcp.client.stdio import stdio_client
   from mcp import ClientSession
   from config import PlaywrightMCPConfig

class PlaywrightMCPClient:
def init(self, config: PlaywrightMCPConfig):
self.config = config
self.session = None

asyncdef connect(self):
    server_params = self.config.get_server_params()
    asyncwith stdio_client(server_params) as (read, write):
        asyncwith ClientSession(read, write) as session:
            self.session = session
            # 初始化会话
            await session.initialize()
            return self

2. 基本网页操作
   class WebAutomationWorkflow:
   def init(self, mcp_client):
   self.client = mcp_client

   asyncdef navigate_to_page(self, url: str):
   """导航到指定页面"""
   result = await self.client.session.call_tool(
   "navigate",
   {"url": url}
   )
   return result

   asyncdef fill_form(self, selector: str, value: str):
   """填写表单"""
   result = await self.client.session.call_tool(
   "fill",
   {"selector": selector, "value": value}
   )
   return result

   asyncdef click_element(self, selector: str):
   """点击元素"""
   result = await self.client.session.call_tool(
   "click",
   {"selector": selector}
   )
   return result

   asyncdef extract_text(self, selector: str):
   """提取文本内容"""
   result = await self.client.session.call_tool(
   "get_text",
   {"selector": selector}
   )
   return result
   集成LLM创建智能工作流

3. LLM任务规划器
   import openai
   from typing import List, Dict, Any

class LLMTaskPlanner:
def init(self, api_key: str):
self.client = openai.OpenAI(api_key=api_key)

def plan_workflow(self, user_request: str) -> List[Dict[str, Any]]:
    """使用LLM解析用户请求并生成工作流步骤"""
    
    prompt = f"""
    根据以下用户请求，生成一个详细的Playwright自动化工作流。
    用户请求: {user_request}
    
    请以JSON格式返回步骤列表，每个步骤包含:
    - action: 操作类型 (navigate, click, fill, extract, wait, etc.)
    - parameters: 操作参数
    - description: 步骤描述
    
    只返回JSON格式的结果。
    """
    
    response = self.client.chat.completions.create(
        model="gpt-4",
        messages=[{"role": "user", "content": prompt}],
        temperature=0.1
    )
    
    return self._parse_response(response.choices[0].message.content)

def _parse_response(self, response: str) -> List[Dict[str, Any]]:
    """解析LLM响应为结构化工作流"""
    import json
    try:
        # 清理响应并提取JSON
        cleaned_response = response.strip()
        if"```json"in cleaned_response:
            cleaned_response = cleaned_response.split("```json")[1].split("```")[0]
        elif"```"in cleaned_response:
            cleaned_response = cleaned_response.split("```")[1]
            
        return json.loads(cleaned_response)
    except Exception as e:
        print(f"解析LLM响应失败: {e}")
        return []

2. 智能工作流执行器
   class IntelligentWorkflowExecutor:
   def init(self, mcp_client, llm_planner):
   self.mcp_client = mcp_client
   self.planner = llm_planner
   self.automation = WebAutomationWorkflow(mcp_client)

   asyncdef execute_user_request(self, user_request: str):
   """执行用户自然语言请求的完整工作流"""

    print(f"处理用户请求: {user_request}")
    
    # 1. 使用LLM规划工作流
    workflow_steps = self.planner.plan_workflow(user_request)
    print(f"生成的工作流步骤: {len(workflow_steps)}步")
    
    # 2. 执行工作流
    results = []
    for i, step in enumerate(workflow_steps, 1):
        print(f"执行步骤 {i}: {step['description']}")
        
        try:
            result = await self._execute_step(step)
            results.append({
                "step": i,
                "description": step["description"],
                "result": result,
                "status": "success"
            })
        except Exception as e:
            results.append({
                "step": i,
                "description": step["description"],
                "error": str(e),
                "status": "failed"
            })
            print(f"步骤 {i} 执行失败: {e}")
            break
            
    return results
   

   asyncdef _execute_step(self, step: Dict[str, Any]):
   """执行单个工作流步骤"""
   action = step["action"]
   params = step["parameters"]

    if action == "navigate":
        returnawait self.automation.navigate_to_page(params["url"])
    elif action == "click":
        returnawait self.automation.click_element(params["selector"])
    elif action == "fill":
        returnawait self.automation.fill_form(params["selector"], params["value"])
    elif action == "extract":
        returnawait self.automation.extract_text(params["selector"])
    elif action == "wait":
        await asyncio.sleep(params.get("seconds", 2))
        return"等待完成"
    else:
        raise ValueError(f"未知操作: {action}")
   

高级应用：构建AI智能体

1. 自适应智能体
   class AdaptiveAIAgent:
   def init(self, mcp_client, llm_planner, executor):
   self.mcp_client = mcp_client
   self.planner = llm_planner
   self.executor = executor
   self.conversation_history = []

   asyncdef process_request(self, user_input: str, context: Dict = None):
   """处理用户输入并执行相应操作"""

    # 添加上下文到对话历史
    self.conversation_history.append({"role": "user", "content": user_input})
    
    # 分析用户意图
    intent = await self._analyze_intent(user_input, context)
    
    if intent["type"] == "automation":
        # 执行自动化工作流
        results = await self.executor.execute_user_request(user_input)
        
        # 生成自然语言总结
        summary = await self._generate_summary(user_input, results)
        
        self.conversation_history.append({
            "role": "assistant", 
            "content": summary
        })
        
        return {
            "type": "automation",
            "results": results,
            "summary": summary
        }
        
    elif intent["type"] == "query":
        # 处理查询请求
        response = await self._handle_query(user_input)
        return {
            "type": "query",
            "response": response
        }
   

   asyncdef _analyze_intent(self, user_input: str, context: Dict) -> Dict:
   """使用LLM分析用户意图"""
   # 简化的意图分析实现
   automation_keywords = ["打开", "点击", "填写", "导航", "提取", "自动化"]

    if any(keyword in user_input for keyword in automation_keywords):
        return {"type": "automation", "confidence": 0.9}
    else:
        return {"type": "query", "confidence": 0.7}
   

   asyncdef _generate_summary(self, request: str, results: List) -> str:
   """生成工作流执行总结"""
   success_steps = [r for r in results if r["status"] == "success"]

    returnf"""
    已完成您的要求: {request}
    
    执行统计:
    - 总步骤数: {len(results)}
    - 成功步骤: {len(success_steps)}
    - 失败步骤: {len(results) - len(success_steps)}
    
    {'所有步骤均成功完成!' if len(success_steps) == len(results) else '部分步骤执行失败，请检查错误信息。'}
    """
   

2. 复杂工作流示例：电商数据采集
   class EcommerceDataAgent:
   def init(self, base_agent):
   self.agent = base_agent

   asyncdef collect_product_data(self, product_url: str, data_points: List[str]):
   """采集电商产品数据"""

    workflow_request = f"""
    请执行以下电商数据采集任务:
    1. 导航到产品页面: {product_url}
    2. 提取产品标题
    3. 提取产品价格
    4. 提取产品评分
    5. 提取产品描述
    6. 提取客户评论数量
    """
    
    # 执行数据采集
    results = await self.agent.process_request(workflow_request)
    
    # 数据清洗和结构化
    structured_data = await self._structure_product_data(results)
    
    return structured_data
   

   asyncdef _structure_product_data(self, raw_results: Dict) -> Dict:
   """将采集的数据结构化"""
   # 实现数据解析和结构化逻辑
   structured = {}

    for result in raw_results.get("results", []):
        if"result"in result and result["result"]:
            # 解析提取的数据
            text_content = result["result"].get("content", "")
            # 根据步骤描述识别数据类型
            if"标题"in result["description"]:
                structured["title"] = self._clean_text(text_content)
            elif"价格"in result["description"]:
                structured["price"] = self._extract_price(text_content)
            elif"评分"in result["description"]:
                structured["rating"] = self._extract_rating(text_content)
                
    return structured
   

   def _clean_text(self, text: str) -> str:
   """清理文本数据"""
   return text.strip() if text else""

   def _extract_price(self, text: str) -> float:
   """提取价格信息"""
   import re
   matches = re.findall(r'[\d.,]+', text)
   return float(matches[0].replace(',', '')) if matches else0.0
   错误处理与优化

3. 鲁棒性增强
   class RobustWorkflowExecutor(IntelligentWorkflowExecutor):
   asyncdef execute_with_retry(self, user_request: str, max_retries: int = 3):
   """带重试机制的工作流执行"""

    for attempt in range(max_retries):
        try:
            results = await self.execute_user_request(user_request)
            
            # 检查是否有失败步骤
            failed_steps = [r for r in results if r["status"] == "failed"]
            ifnot failed_steps:
                return results
                
            print(f"第 {attempt + 1} 次尝试，{len(failed_steps)} 个步骤失败")
            
            # 最后一次尝试仍然失败，抛出异常
            if attempt == max_retries - 1:
                raise Exception(f"工作流执行失败，{len(failed_steps)} 个步骤未完成")
                
        except Exception as e:
            print(f"第 {attempt + 1} 次尝试失败: {e}")
            if attempt == max_retries - 1:
                raise
                
        await asyncio.sleep(2)  # 重试前等待
        
    return []
   

   asyncdef _execute_step_with_fallback(self, step: Dict):
   """带备用方案的步骤执行"""
   try:
   returnawait self._execute_step(step)
   except Exception as e:
   print(f"步骤执行失败: {e}，尝试备用方案")

        # 实现备用执行逻辑
        if step["action"] == "click":
            # 尝试不同的选择器
            returnawait self._try_alternative_selectors(step)
        elif step["action"] == "extract":
            # 尝试不同的数据提取方法
            returnawait self._try_alternative_extraction(step)
        else:
            raise
   

4. 性能监控
   import time
   from dataclasses import dataclass
   from typing import List

@dataclass
class PerformanceMetrics:
total_steps: int
successful_steps: int
failed_steps: int
total_time: float
average_step_time: float

class PerformanceMonitor:
def init(self):
self.metrics_history: List[PerformanceMetrics] = []

def start_execution(self):
    self.start_time = time.time()
    self.step_times = []
    
def record_step(self, success: bool, step_time: float):
    self.step_times.append(step_time)
    
def end_execution(self, total_steps: int, successful_steps: int):
    total_time = time.time() - self.start_time
    avg_time = sum(self.step_times) / len(self.step_times) if self.step_times else0
    
    metrics = PerformanceMetrics(
        total_steps=total_steps,
        successful_steps=successful_steps,
        failed_steps=total_steps - successful_steps,
        total_time=total_time,
        average_step_time=avg_time
    )
    
    self.metrics_history.append(metrics)
    return metrics

实际应用场景

1. 自动化测试智能体
   class TestingAutomationAgent:
   def init(self, base_agent):
   self.agent = base_agent

   async def run_e2e_test(self, test_scenario: str):
   """执行端到端测试"""
   test_request = f"""
   执行以下端到端测试场景:

    包括:
    1. 导航到测试页面
    2. 执行测试步骤
    3. 验证预期结果
    4. 生成测试报告
    """
    
    return await self.agent.process_request(test_request)
   

2. 数据监控智能体
   class MonitoringAgent:
   def init(self, base_agent, alert_thresholds: Dict):
   self.agent = base_agent
   self.thresholds = alert_thresholds

   asyncdef monitor_website(self, url: str, check_interval: int = 3600):
   """定期监控网站状态"""
   whileTrue:
   try:
   status = await self._check_website_status(url)

            ifnot status["is_healthy"]:
                await self._send_alert(f"网站异常: {status['issues']}")
                
        except Exception as e:
            await self._send_alert(f"监控检查失败: {e}")
            
        await asyncio.sleep(check_interval)
   

   asyncdef _check_website_status(self, url: str) -> Dict:
   """检查网站健康状态"""
   check_request = f"""
   检查网站健康状况:
   1. 访问 {url}
   2. 检查页面加载时间
   3. 验证关键功能是否正常
   4. 检查错误信息
   """

    results = await self.agent.process_request(check_request)
    return self._analyze_health_status(results)
   

结论
通过结合Playwright MCP和LLM，我们能够构建强大的AI智能体和工作流系统，这些系统能够：

理解自然语言指令并转化为具体操作
自动化复杂业务流程，减少人工干预
自适应处理异常情况，提高系统鲁棒性
持续学习和优化执行策略
这种技术组合为自动化测试、数据采集、监控警报等场景提供了全新的解决方案。随着AI技术的不断发展，这种模式将在更多领域展现其价值，推动企业数字化转型和智能化升级。

Playwright MCP与LLM的结合只是AI驱动自动化的开始，这个领域的发展潜力无限，值得我们持续关注和探索。

推荐学习
Playwright web 爬虫与AI智能体课程，限时免费，机会难得。扫码报名，参与直播，希望您在这场公开课中收获满满，开启智能自动化测试的新篇章！