from agents import Agent, ModelSettings, Runner, function_tool
from agents.extensions.models.litellm_model import LitellmModel
from openai.types.shared import Reasoning


@function_tool
def echo_tool(input: str) -> str:
    return input

model = LitellmModel(
    model="claude-opus-4-5-20251101",
)

agent = Agent(
    name="Assistant",
    instructions="You are a helpful assistant",
    model=model,
    tools=[echo_tool],
    model_settings=ModelSettings(reasoning=Reasoning(effort="low"))
)

print("================ Turn 1")

result = Runner.run_sync(
    agent, "Can you use the echo_tool to echo the message 'Hello, world!'?"
)
print(result.final_output)
print("------")
print(result.to_input_list())
print("------")

print("================ Turn 2")

messages = result.to_input_list()

messages.append( { "role": "user", "content": "Can you use the echo_tool to echo the message 'Hello, world!'?"})

result = Runner.run_sync(
     agent, messages
 )

print(result.final_output)
print("------")
print(result.to_input_list())