Error when using MultiPromptOptimizer with MLX model

[tandetat]

Hi,

So when using langmem’s create_multi_prompt_optimizer from a MLXPipeline-loaded model, I get an error inside the GradientPromptOptimizer because it passes two tools and tool_choice=“any” to bind_tools in https://github.com/langchain-ai/langmem/blame/10448879b8815a7c5ee286556528d78bc721f32c/src/langmem/prompts/gradient.py#L150

This line returns an error when we pass more than one tool and set tool_choice:
https://github.com/langchain-ai/langchain-community/blame/bc87773064735e649cfd798185502e156d5e948a/libs/community/langchain_community/chat_models/mlx.py#L249

Am I using this wrong, or should this line also check if tool_choice == “any” or this limit on the length of tools outdated?