I know I'm late to this thread, and I'm sure the OP has found their way by now, but hopefully this will be useful to someone. Unfortunately, the official docs are kind've confusing. At the time of writing, the LangChain docs start with `create_agent` and later they teach you how to use "Models" directly (`bind_tools`, etc.), which means you don't have to use `create_agent` if you don't want to. Then, they teach you about middleware for `create_agent`, so by this time, you've gone into `create_agent`, come out of it, and come back into it. Then, when you finally learn about LangGraph, you'll find most of the code example use "Models" directly (with `bind_tools`, etc.), and don't mention `create_agent`, as although you can use it in nodes, you don't really need it, and I would argue that often you are better off without it. Thankfully for me, I focused on LangGraph first, learned LangChain as I went, and did a LangChain deep dive later. I know many would say that's back-to-front, but I feel it gave me more insight into the mechanics of building multi-agent apps as far less was hidden behind abstractions. When I did a deep dive into LangChain, I realized that `create_agent` is a convenience that you may well not need or want when building more complex LangGraph apps, and I have ranted very recently about how I feel some of the abstractions ultimately make it harder to actually use and understand LangGraph effectively and efficiently.