> Such a shame that there's nothing to replace Langchain with other than writing it all from the ground up yourself.

Check out Microsoft Semantic Kernel: https://github.com/microsoft/semantic-kernel

Supports .NET, Java, and Python. Lots of sample code[0] and support for agents[1] including a detailed guide[2].

We use it at our startup (the .NET version). It was initially quite unstable in the early days because of frequent breaking changes, but it has stabilized (for the most part). Note: the official docs may still be trailing, but the code samples in the repo and unit tests are up to date.

Highly recommended.

[0] https://github.com/microsoft/semantic-kernel/tree/main/pytho...

[1] https://github.com/microsoft/semantic-kernel/tree/main/pytho...

[2] https://github.com/microsoft/semantic-kernel/tree/main/pytho...