Python: [Bug]: HostedWebSearchTool failed with AzureOpenAIChatClient

[TaoChenOSU]

Description

Bug: HostedWebSearchTool failed with AzureOpenAIChatClient
Error message:

agent_framework.exceptions.ServiceResponseException: <class 'agent_framework.azure._chat_client.AzureOpenAIChatClient'> service failed to complete the prompt: Error code: 400 - {'error': {'message': "Unknown parameter: 'web_search_options'.", 'type': 'invalid_request_error', 'param': 'web_search_options', 'code': 'unknown_parameter'}}

Repro: Run this sample with an AzureOpenAIChatClient: https://github.com/microsoft/agent-framework/blob/main/python/samples/getting_started/agents/openai/openai_chat_client_with_web_search.py

Package Versions

agent-framework-core

Python Version

No response

Additional Context

Model: gpt-5-mini

If I removed the web_search_options, it fixed the issue.