idk man

https://js.langchain.com/docs/introduction/

https://www.vellum.ai/products/workflows-sdk

https://github.com/transitive-bullshit/agentic

which is not to say any of them got it right or wrong, but it is by no means "missing". the big question w all of them is do they deliver enough value to last. kudos to those who at least try, of course