[BUG] 0.1.7 Pydantic @tool parameter regression

[JoshuaToth]

Checks

• I have updated to the lastest minor and patch version of Strands
• I have checked the documentation and this is not expected behavior
• I have searched ./issues and there are no duplicates of my issue

Strands Version

0.1.7

Python Version

3.13.2

Operating System

macOS (Also Lambda)

Installation Method

pip

Steps to Reproduce

1. Install strands-agents version 0.1.7

2. run the below in an index.py

from pydantic import BaseModel
from strands import Agent, tool, models


class StoryboardEntry(BaseModel):
    sceneIndex: int
    sceneDescription: str
    sceneType: str


@tool
def save_full_storyboard(storyboard_data: StoryboardEntry):
    print(storyboard_data)
    return "done"


bedrock_model = models.BedrockModel(
    model="anthropic.claude-3-5-sonnet-20241022-v2:0",
    max_tokens=40000,
    region_name="us-west-2"
)

agent = Agent(
        model=bedrock_model,
        tools=[save_full_storyboard]
    )

agent("Your task is to generate a children's novel storyboard scene")

Expected Behavior

Pydantic types can be used as method parameter.

Actual Behavior

Tool error:

botocore.exceptions.EventStreamError: An error occurred (validationException) when calling the ConverseStream operation: The model returned the following errors: tools.0.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://docs.anthropic.com/en/docs/tool-use.

Full stacktrace

Traceback (most recent call last):
  File "/Users/joshtoth/dev/strands-test/index.py", line 29, in <module>
    agent("Your task is to generate a childrens novel storyboard")
    ~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/agent/agent.py", line 358, in __call__
    result = self._run_loop(prompt, kwargs)
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/agent/agent.py", line 462, in _run_loop
    return self._execute_event_loop_cycle(invocation_callback_handler, kwargs)
           ~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/agent/agent.py", line 490, in _execute_event_loop_cycle
    stop_reason, message, metrics, state = event_loop_cycle(
                                           ~~~~~~~~~~~~~~~~^
        model=model,
        ^^^^^^^^^^^^
    ...<9 lines>...
        **kwargs,
        ^^^^^^^^^
    )
    ^
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/event_loop/event_loop.py", line 190, in event_loop_cycle
    raise e
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/event_loop/event_loop.py", line 148, in event_loop_cycle
    stop_reason, message, usage, metrics, kwargs["request_state"] = stream_messages(
                                                                    ~~~~~~~~~~~~~~~^
        model,
        ^^^^^^
    ...<4 lines>...
        **kwargs,
        ^^^^^^^^^
    )
    ^
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/event_loop/streaming.py", line 340, in stream_messages
    return process_stream(chunks, callback_handler, messages, **kwargs)
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/event_loop/streaming.py", line 290, in process_stream
    for chunk in chunks:
                 ^^^^^^
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/types/models/model.py", line 115, in converse
    for event in response:
                 ^^^^^^^^
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/models/bedrock.py", line 369, in stream
    raise e
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/strands/models/bedrock.py", line 331, in stream
    for chunk in response["stream"]:
                 ~~~~~~~~^^^^^^^^^^
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/botocore/eventstream.py", line 592, in __iter__
    parsed_event = self._parse_event(event)
  File "/Users/joshtoth/dev/strands-test/.venv/lib/python3.13/site-packages/botocore/eventstream.py", line 608, in _parse_event
    raise EventStreamError(parsed_response, self._operation_name)
botocore.exceptions.EventStreamError: An error occurred (validationException) when calling the ConverseStream operation: The model returned the following errors: tools.0.custom.input_schema: JSON schema is invalid. It must match JSON Schema draft 2020-12 (https://json-schema.org/draft/2020-12). Learn more about tool use at https://docs.anthropic.com/en/docs/tool-use.

Additional Context

3. Either change the method to just use a 'str' or change back to version 0.1.6 and it works again.

Possible Solution

No response

Related Issues

No response