Update app.py

app.py

@@ -9,10 +9,12 @@ os.environ["LANGCHAIN_PROJECT"] = "langgraph-multi-agent"
 def invoke(openai_api_key, prompt):
     if (openai_api_key == ""):
         raise gr.Error("OpenAI API Key is required.")
+    if (prompt == ""):
+        raise gr.Error("Prompt is required.")
         
     os.environ["OPENAI_API_KEY"] = openai_api_key
    
-    return "TODO"
+    return run_multi_agent(prompt)
 
 gr.close_all()