chore: import upstream snapshot with attribution

examples/integrations/langgraph-python/agent/main.py

@@ -0,0 +1,45 @@
+"""
+This is the main entry point for the agent.
+It defines the workflow graph, state, tools, nodes and edges.
+"""
+
+from copilotkit import CopilotKitMiddleware, StateStreamingMiddleware, StateItem
+from langchain.agents import create_agent
+
+# Data & state tools
+from src.query import query_data
+from src.todos import AgentState, todo_tools
+
+# A2UI tools
+from src.a2ui_dynamic_schema import generate_a2ui
+from src.a2ui_fixed_schema import search_flights
+
+from langchain_openai import ChatOpenAI
+
+model = ChatOpenAI(model="gpt-5.4-mini", model_kwargs={"parallel_tool_calls": False})
+
+agent = create_agent(
+    model=model,
+    tools=[query_data, *todo_tools, generate_a2ui, search_flights],
+    middleware=[
+        CopilotKitMiddleware(),
+        StateStreamingMiddleware(
+            StateItem(state_key="todos", tool="manage_todos", tool_argument="todos")
+        ),
+    ],
+    state_schema=AgentState,
+    system_prompt="""
+        You are a polished, professional demo assistant. Keep responses to 1-2 sentences.
+
+        Tool guidance:
+        - Flights: call search_flights to show flight cards with a pre-built schema.
+        - Dashboards & rich UI: call generate_a2ui to create dashboard UIs with metrics,
+          charts, tables, and cards. It handles rendering automatically.
+        - Charts: call query_data first, then render with the chart component.
+        - Todos: enable app mode first, then manage todos.
+        - A2UI actions: when you see a log_a2ui_event result (e.g. "view_details"),
+          respond with a brief confirmation. The UI already updated on the frontend.
+    """,
+)
+
+graph = agent