feat: update langgraph stdio demo output format

Author: LishuaiJing3

.DS_Store

@@ -3,11 +3,14 @@
 import asyncio
 import os
 from dotenv import load_dotenv
+from collections import namedtuple
 
 from langchain_mcp_adapters.client import MultiServerMCPClient
 from langgraph.prebuilt import create_react_agent
 import openai
 
+from .utils import render_utility_result
+
 load_dotenv()
 openai.api_key = os.getenv("OPENAI_API_KEY")
 
@@ -27,7 +30,7 @@ async def main():
     for t in tools:
         print(f" • {t.name}")
 
-    agent = create_react_agent("openai:gpt-4o", tools)
+    agent = create_react_agent("openai:gpt-4.1", tools)
 
     tests = [
         ("about_info",    "Call the 'about_info' tool."),
@@ -36,12 +39,35 @@ async def main():
         ("dependency_scan","Call 'dependency_scan' on path '../'."),
     ]
 
+    TextContent = namedtuple('TextContent', ['text'])
+    ToolResult = namedtuple('ToolResult', ['content', 'isError'])
+
     for name, prompt in tests:
         print(f"\n--- {name} → {prompt}")
-        resp = await agent.ainvoke({
-            "messages": [{"role": "user", "content": prompt}]
-        })
-        print(resp)
+        tool_outputs = []
+        agent_final_response = None
+
+        # Stream through the agent's steps
+        async for chunk in agent.astream({"messages": [{"role": "user", "content": prompt}]}
+            ):
+            if "tools" in chunk:
+                tool_outputs.extend(chunk["tools"]["messages"])
+            if "agent" in chunk:
+                # The agent's message is the latest one in the list
+                message = chunk["agent"]["messages"][-1]
+                # If it's a final response (no more tool calls), we save it.
+                if not message.tool_calls:
+                    agent_final_response = message
+
+        # Render the collected outputs. Prioritize tool output.
+        if tool_outputs:
+            # To make the output identical, we remove the "Tool output:" header
+            for msg in tool_outputs:
+                mock_result = ToolResult(content=[TextContent(text=msg.content)], isError=False)
+                render_utility_result(mock_result)
+        elif agent_final_response:
+            # Only if no tool was called, print the agent's response.
+            print(agent_final_response.content)
 
 if __name__ == "__main__":
-    asyncio.run(main())
+    asyncio.run(main())