On: Why we no longer use LangChain for building our AI...

[pveierland]

Using Llama Index for this via the `llama_index.core.base.llms.base.BaseLLM` interface. Using config files to describe the args to different models makes swapping models literally as easy as:

  chat_model:
    cls: llama_index.llms.openai.OpenAI
    kwargs:
      model: gpt-4

  chat_model:
    cls: llama_index.llms.gemini.Gemini
    kwargs:
      model_name: models/gemini-pro