File ".venv/lib/python3.12/site-packages/pydantic_ai/models/instrumented.py", line 381, in request_stream async with self.wrapped.request_stream( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File "/opt/homebrew/anaconda3/lib/python3.12/contextlib.py", line 210, in __aenter__ return await anext(self.gen) ^^^^^^^^^^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/pydantic_ai/models/bedrock.py", line 289, in request_stream response = await self._messages_create(messages, True, settings, model_request_parameters) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/pydantic_ai/models/bedrock.py", line 412, in _messages_create model_response = await anyio.to_thread.run_sync(functools.partial(self.client.converse_stream, **params)) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/anyio/to_thread.py", line 56, in run_sync return await get_async_backend().run_sync_in_worker_thread( ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/anyio/_backends/_asyncio.py", line 2470, in run_sync_in_worker_thread return await future ^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/anyio/_backends/_asyncio.py", line 967, in run result = context.run(func, *args) ^^^^^^^^^^^^^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/botocore/client.py", line 602, in _api_call return self._make_api_call(operation_name, kwargs) ^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/botocore/context.py", line 123, in wrapper return func(*args, **kwargs) ^^^^^^^^^^^^^^^^^^^^^ File ".venv/lib/python3.12/site-packages/botocore/client.py", line 1078, in _make_api_call raise error_class(parsed_response, operation_name) botocore.errorfactory.ValidationException: An error occurred (ValidationException) when calling the ConverseStream operation: The model returned the following errors: Thinking may not be enabled when tool_choice forces tool use.

import asyncio from pydantic import BaseModel from pydantic_ai import Agent from pydantic_ai.models.anthropic import AnthropicModelSettings from pydantic_ai.models.bedrock import BedrockConverseModel # Define a simple tool def get_current_time() -> str: """Get the current time.""" from datetime import datetime return datetime.now().isoformat() # Define a simple structured output type for this example class SimpleOutput(BaseModel): """Simple structured output.""" summary: str timestamp: str # Model settings that trigger the bug model_settings = { "max_tokens": 63000, "temperature": 1.0, "timeout": 300, "parallel_tool_calls": True, "bedrock_additional_model_requests_fields": { "anthropic_beta": [ "token-efficient-tools-2025-02-19", "interleaved-thinking-2025-05-14" ], "thinking": { "type": "enabled", "budget_tokens": 4096 } } } # Create the Bedrock model model = BedrockConverseModel( model_name="us.anthropic.claude-sonnet-4-5-20250929-v1:0", settings=AnthropicModelSettings(**model_settings) ) # Create agent with tool agent = Agent( model=model, tools=[get_current_time], system_prompt="You are a helpful assistant. Use the get_current_time tool to provide accurate timestamps." ) async def main(): """Run the agent and trigger the error.""" # This prompt should trigger tool usage prompt = "What is the current time?" nodes = [] # Using iter() with output_type triggers the bug when tools are needed async with agent.iter(prompt, output_type=SimpleOutput) as agent_run: async for node in agent_run: nodes.append(node) result = agent_run.result.output print("\n\nResult:", result) if __name__ == "__main__": asyncio.run(main())