Configure `failure_error_function` in FunctionTool class

[panilya]

Describe the feature

In the @function_tool is it possible to provide custom failure_error_function: ToolErrorFunction | None = default_tool_error_function.

However, when trying to init FunctionTool via class FunctionTool it is not possible to configure failure_error_function and the default one is used.

Please, add support of ToolErrorFunction configuration in class FunctionTool

Expected result:

    function_tool = FunctionTool(
      name=action.name,
      description=action.description,
      params_json_schema=schema,
      on_invoke_tool=handle_tool_call_invoke,
      failure_error_function=tool_error_function <---- new field
    )

[seratch]

Thanks for asking the question. You can pass the error function to the decorator like these examples in unit tests do: https://github.com/openai/openai-agents-python/blob/main/tests/test_function_tool_decorator.py

This document page slightly mentions this, but having code snippets as well might be more developer-friendly.