add mcp use method

2025-09-01 11:59:17 +08:00
parent 9435767fb1
commit 87a7f3f9df
7 changed files with 559 additions and 0 deletions
--- a/examples/mcp_modes/plan_and_execute.py
+++ b/examples/mcp_modes/plan_and_execute.py
@@ -0,0 +1,61 @@
+# examples/mcp_modes/plan_and_execute.py
+import os, asyncio
+from typing import List
+from langchain_core.messages import HumanMessage, ToolMessage
+from langgraph_qwen.chat_model import ChatQwenOpenAICompat
+from langgraph_qwen.mcp import load_mcp_tools
+
+async def plan(task: str) -> List[str]:
+    planner = ChatQwenOpenAICompat(temperature=0)
+    ai = await planner.ainvoke([HumanMessage(content=f"把任务拆成可执行步骤（每行一步）：\n{task}")])
+    steps = [s.strip() for s in str(ai.content).splitlines() if s.strip()]
+    return steps[:8]
+
+async def tools_for_step(step_idx: int):
+    # ★ 示例：偶数步用 weather，奇数步用 play/test 工具；也可来自文件
+    if step_idx % 2 == 0:
+        return await load_mcp_tools(servers={
+            "weather": {"url":"http://127.0.0.1:8000/mcp/","transport":"streamable_http"}
+        })
+    else:
+        cfg = os.getenv("MCP_CONFIG_PATH")  # 比如 ./mcp_servers.yaml
+        return await load_mcp_tools(config_path=cfg)
+
+async def execute(steps: List[str], max_tool_steps_per_step: int = 4):
+    msgs = []
+    for i, step in enumerate(steps, 1):
+        tools = await tools_for_step(i)
+        tool_map = {t.name: t for t in tools}
+        model = ChatQwenOpenAICompat(temperature=0).bind_tools(tools).bind(tool_choice="auto")
+
+        msgs.append(HumanMessage(content=f"执行第{i}步：{step}"))
+        for _ in range(max_tool_steps_per_step):
+            ai = await model.ainvoke(msgs)
+            msgs.append(ai)
+            calls = getattr(ai, "tool_calls", []) or ai.additional_kwargs.get("tool_calls", [])
+            if not calls:
+                break
+            for call in calls:
+                name, args, call_id = call.get("name"), call.get("args", {}), call.get("id") or ""
+                tool = tool_map.get(name)
+                if not tool:
+                    msgs.append(ToolMessage(tool_call_id=call_id, content=f"Unknown tool: {name}"))
+                    continue
+                try:
+                    out = await tool.ainvoke(args) if hasattr(tool, "ainvoke") else tool.invoke(args)
+                    msgs.append(ToolMessage(tool_call_id=call_id, content=str(out)))
+                except Exception as e:
+                    msgs.append(ToolMessage(tool_call_id=call_id, content=f"Error: {e}"))
+
+    final = await ChatQwenOpenAICompat(temperature=0).ainvoke(
+        msgs + [HumanMessage(content="请汇总执行结果，简洁给出结论。")]
+    )
+    print("=== Final ===")
+    print(final.content)
+
+async def main():
+    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")
+    await execute(steps, max_tool_steps_per_step=4)
+
+if __name__ == "__main__":
+    asyncio.run(main())