62 lines
2.7 KiB
Python
62 lines
2.7 KiB
Python
# examples/mcp_modes/plan_and_execute.py
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import os, asyncio
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from typing import List
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from langchain_core.messages import HumanMessage, ToolMessage
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from langgraph_qwen.chat_model import ChatQwenOpenAICompat
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from langgraph_qwen.mcp import load_mcp_tools
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async def plan(task: str) -> List[str]:
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planner = ChatQwenOpenAICompat(temperature=0)
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ai = await planner.ainvoke([HumanMessage(content=f"把任务拆成可执行步骤（每行一步）：\n{task}")])
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steps = [s.strip() for s in str(ai.content).splitlines() if s.strip()]
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return steps[:8]
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async def tools_for_step(step_idx: int):
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# ★ 示例：偶数步用 weather，奇数步用 play/test 工具；也可来自文件
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if step_idx % 2 == 0:
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return await load_mcp_tools(servers={
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"weather": {"url":"http://127.0.0.1:8000/mcp/","transport":"streamable_http"}
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})
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else:
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cfg = os.getenv("MCP_CONFIG_PATH") # 比如 ./mcp_servers.yaml
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return await load_mcp_tools(config_path=cfg)
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async def execute(steps: List[str], max_tool_steps_per_step: int = 4):
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msgs = []
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for i, step in enumerate(steps, 1):
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tools = await tools_for_step(i)
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tool_map = {t.name: t for t in tools}
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model = ChatQwenOpenAICompat(temperature=0).bind_tools(tools).bind(tool_choice="auto")
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msgs.append(HumanMessage(content=f"执行第{i}步：{step}"))
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for _ in range(max_tool_steps_per_step):
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ai = await model.ainvoke(msgs)
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msgs.append(ai)
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calls = getattr(ai, "tool_calls", []) or ai.additional_kwargs.get("tool_calls", [])
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if not calls:
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break
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for call in calls:
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name, args, call_id = call.get("name"), call.get("args", {}), call.get("id") or ""
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tool = tool_map.get(name)
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if not tool:
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msgs.append(ToolMessage(tool_call_id=call_id, content=f"Unknown tool: {name}"))
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continue
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try:
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out = await tool.ainvoke(args) if hasattr(tool, "ainvoke") else tool.invoke(args)
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msgs.append(ToolMessage(tool_call_id=call_id, content=str(out)))
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except Exception as e:
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msgs.append(ToolMessage(tool_call_id=call_id, content=f"Error: {e}"))
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final = await ChatQwenOpenAICompat(temperature=0).ainvoke(
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msgs + [HumanMessage(content="请汇总执行结果，简洁给出结论。")]
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)
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print("=== Final ===")
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print(final.content)
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async def main():
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steps = await plan("在巴塞罗那找一个带游泳池的民宿，然后搜索附近的餐厅和景点")
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await execute(steps, max_tool_steps_per_step=4)
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if __name__ == "__main__":
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asyncio.run(main())
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