I'm somewhat in agreement. I like building 1:1 code for that specific agent.

Where I'm starting to question this is maintainability. When I come up with a new technique or way of doing something in my new agent, how can I update an older agent. Do I want to update the older agent?

But, I get what you're talking about w.r.t. building for the exact problem at hand. For example, I'm guessing that Apache Burr has support for a plugin-able vector RAG system (or at least it will if it doesn't now). That's great, but I want my RAG system to add documents to the context and keep them as part of an updated system prompt with some very specific tweaks that happen as part of that process. This is a bespoke way of working with an existing concept (RAG) that doesn't lend itself to using any specific framework.

In my use-case, bespoke is the way to go. But then I'm still stuck with having to make engineering choices for updating older agents. So, I see your point.