Zed strikes a good balance I think with their non-agentic text threads feature. You use slash commands to add whatever you need to the context (single files, directories, highlighted selections, etc) and interact with a conventional chat interface from there. The prompt library also lets you store convenient system prompts if you have a diverse task domain.

You can of course use their new agentic features which can automate a lot of the context management via tool use, but I find that to be a waste of time and resources for the majority of tasks I care about.

I currently manage my own fork to use a custom FIM completion provider I built, that tends to do most of the heavy lifting for me in terms of anything AI-generated.