chore: import upstream snapshot with attribution

examples/agent_patterns/agents_as_tools_streaming.py

@@ -0,0 +1,59 @@
+import asyncio
+
+from agents import Agent, AgentToolStreamEvent, ModelSettings, Runner, function_tool, trace
+
+
+@function_tool(
+    name_override="billing_status_checker",
+    description_override="Answer questions about customer billing status.",
+)
+def billing_status_checker(customer_id: str | None = None, question: str = "") -> str:
+    """Return a canned billing answer or a fallback when the question is unrelated."""
+    normalized = question.lower()
+    if "bill" in normalized or "billing" in normalized:
+        return f"This customer (ID: {customer_id})'s bill is $100"
+    return "I can only answer questions about billing."
+
+
+def handle_stream(event: AgentToolStreamEvent) -> None:
+    """Print streaming events emitted by the nested billing agent."""
+    stream = event["event"]
+    tool_call = event.get("tool_call")
+    tool_call_info = tool_call.call_id if tool_call is not None else "unknown"
+    print(f"[stream] agent={event['agent'].name} call={tool_call_info} type={stream.type} {stream}")
+
+
+async def main() -> None:
+    with trace("Agents as tools streaming example"):
+        billing_agent = Agent(
+            name="Billing Agent",
+            instructions="You are a billing agent that answers billing questions.",
+            model_settings=ModelSettings(tool_choice="required"),
+            tools=[billing_status_checker],
+        )
+
+        billing_agent_tool = billing_agent.as_tool(
+            tool_name="billing_agent",
+            tool_description="You are a billing agent that answers billing questions.",
+            on_stream=handle_stream,
+        )
+
+        main_agent = Agent(
+            name="Customer Support Agent",
+            instructions=(
+                "You are a customer support agent. Always call the billing agent to answer billing "
+                "questions and return the billing agent response to the user."
+            ),
+            tools=[billing_agent_tool],
+        )
+
+        result = await Runner.run(
+            main_agent,
+            "Hello, my customer ID is ABC123. How much is my bill for this month?",
+        )
+
+    print(f"\nFinal response:\n{result.final_output}")
+
+
+if __name__ == "__main__":
+    asyncio.run(main())