I can't speak for parent, but I use gptel, and it sounds like they do as well. It has a number of features, but primarily it just gives you a chat buffer you can freely edit at any time. That gives you 100% control over the context, you just quickly remove the parts of the conversation where the LLM went off the rails and keep it clean. You can replace or compress the context so far any way you like.

While I also use LLMs in other ways, this is my core workflow. I quickly get frustrated when I can't _quickly_ modify the context.

If you have some mastery over your editor, you can just run commands and post relevant output and make suggested changes to get an agent like experience, at a speed not too different from having the agent call tools. But you retain 100% control over the context, and use a tiny fraction of the tokens OpenCode and other agents systems would use.

It's not the only or best way to use LLMs, but I find it incredibly powerful, and it certainly has it's place.

A very nice positive effect I noticed personally is that as opposed to using agents, I actually retain an understanding of the code automatically, I don't have to go in and review the work, I review and adjust on the fly.