Python: Agents - Chat throwing "A conversation must alternate between user and assistant roles. Make sure the conversation alternates between user and assistant roles and try again."

[sophialagerkranspandey]

Discussed in #10271

^{Originally posted by yarns123 January 23, 2025}
Hi,

im trying to use this example https://github.com/microsoft/semantic-kernel/blob/main/python/samples/getting_started_with_agents/step3_chat.py with AWS Bedrock Claude Sonnet 3.5. Unfortunately I get this error:
botocore.errorfactory.ValidationException: An error occurred (ValidationException) when calling the Converse operation: A conversation must alternate between user and assistant roles. Make sure the conversation alternates between user and assistant roles and try again.

It seems that ChatHistory for this model cannot have two consecutive responses from the assistant. I would be grateful for any ideas on how to solve this problem

[TaoChenOSU]

Although AWS didn't provide the details on their docs, I was able to find this on Anthropic's API doc: https://docs.anthropic.com/en/api/messages#body-messages

Looks like the Anthropic models do require alternating user and assistant messages.

Could you please try another model that is available on AWS Bedrock?