crossmodel-gemini-to-claude.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

gemini_model = LitellmModel(
    model="gemini/gemini-3-pro-preview"
)
gemini_agent = Agent(
    name="GeminiAssistant",
    instructions="You are a helpful assistant",
    model=gemini_model,
    tools=[echo_tool, speak_tool, final_tool],
    model_settings=ModelSettings(reasoning=Reasoning(effort="low"))
)

claude_model = LitellmModel(
    model="anthropic/claude-sonnet-4-5-20250929"
)
claude_agent = Agent(
    name="Assistant",
    instructions="You are a helpful assistant",
    model=claude_model,
    tools=[echo_tool, speak_tool, final_tool],
    model_settings=ModelSettings(reasoning=Reasoning(effort="low"))
)


print("================================================ Turn 1: Gemini")
result = Runner.run_sync(
    gemini_agent, "think about life, then use echo_tool"
)
print(result.final_output)
print("---------------------------")
messages = result.to_input_list()
print(messages)


print("================================================ Turn 2: Claude")


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

result = Runner.run_sync(
    claude_agent, messages
)

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

print("================================================ Turn 3: Gemini")


messages.append( { "role": "user", "content": "call final_tool"})

result = Runner.run_sync(
    gemini_agent, messages
)

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

# 2025/12/6 error
# litellm.exceptions.BadRequestError: litellm.BadRequestError: AnthropicException - {"type":"error","error":{"type":"invalid_request_error","message":"messages.1.content.0: 
# Invalid `signature` in `thinking` block"},"request_id":"req_011CVqQo9rrz1hsJodYkeirG"}