my biggest code smell is debugging. Trying to step through the code is slow because of how much the debugger has to keep track off and it's a lot of step into / jumps until you get to the piece you actually care about. Then you also see stuff like "if langchain_v2: <branch> elif langchain_v3: <branch> else ...." ... breaking changes are ok! I feel like at this point they're hopelessly spaghettied and need a more opinionated approach to clean up a lot of the mess.

Since others are asking: My current goto is pydantic ai and it's been doing pretty well for my use cases.

It (and most other systems) abstract the wrong concepts when you want to create an agent. They promote what was likely never a great strategy but even parsimoniously what are strategies that were good ideas months or a year back.

For example how langchain or whatever else handles subagents and deep research is laughable even today.

So whats the recommendation? Just use pydantic and code everything up yourself. Maybe strands I dont know.