litellm-gemini3.py

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:
    print("called echo_tool")
    return input

@function_tool
def speak_tool(input: str) -> str:
    print("called speak_tool")
    return input

@function_tool
def final_tool(input: str) -> str:
    print("called final_tool")
    return input

model = LitellmModel(
    model="gemini/gemini-3-pro-preview"
)

agent = Agent(
    name="Assistant",
    instructions="You are a helpful assistant",
    model=model,
    tools=[echo_tool, speak_tool, final_tool],
    model_settings=ModelSettings(reasoning=Reasoning(effort="low"))
)
print("================================================ Turn 1")
result = Runner.run_sync(
    agent, "think about life, then use echo_tool and speak_tool"
)
print(result.final_output)
print("----------")
messages = result.to_input_list()
print(messages)

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

messages.append( { "role": "user", "content": "summarize the above content, then use final_tool"})

result = Runner.run_sync(
    agent, messages
)

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