> * there is LangChain and LangGraph - used a lot, but framework bloat is hated as well

I've used them a fair bit, and I'm not a huge fan. Only self-hosted, I can't comment on their cloud-SaaS agent runner thing. The observability looks neat, though.

LangChain is nice enough, I appreciate having a unified API across providers. LangGraph is... just not all that much? As in the DAG is too much for a simple agent, but when I start thinking about a large agent and dealing with that flow in their their DAG DSL my head starts to hurt. "Go To Definition" isn't going to help navigate that very well, the state is going to be a lot of Optional's with not a lot of info on when they have a real value at which stages in the DAG.

I had substantial issues with branches in my DAG because the state has to include all possible fields for every step. It gets hard to mentally track all the combinations of fields that will be present or missing depending on the path taken upstream of this node. Do I have RAG results? Not sure, it depends on whether the query includes X, but then later it also depends on whether a tool returns a particular result, in which case it can either be missing, have a single value or have 2 values. Yada yada, in a sufficiently large DAG it gets hard to track those. Things are much cleaner in function world where you can declare "this functions require X and Y, and can optionally provide Z".

I mostly go directly to the API these days, but I'm fairly settled on Ollama. I might use LangChain if I think I'll want another backend, but I also might use OpenRouter. I haven't yet, but it seems cool.