I thought it supported a few use cases:

* Testing prompt behavior across various LLMs * Sharing those prompts across multiple applications

We currently use a jupyter notebook to iterate, test, and validate prompts. Then move those prompts to our production app written in C#. If there were a C# SDK, I could use this tool to create a prompts config file and share it between the jupyter notebook and the C# app. The config file could also be added to version control.

Having said that, I don't understand why it saves the output of the LLM so maybe I'm missing something.

https://aiconfig.lastmileai.dev/docs/basics

If you enjoy the OpenAI's playground, this looks pretty much like that but you can use other LLMs.

It seems to be a config file format, library for loading it, interactive editor for it, and playground that uses it.

JSON and YAML, but it also supports connectivity to a bunch of LLMs (including image models like Dall-e 3) and some prompt chaining.

Using models from any provider or modality in a single playground

Looks like you can switch models and use the same prompts very quickly.