[quantadev]

The first chatbot I wrote back in early 2023, had exactly this (branching and history editing), and I was highly active on the OpenAI discord showing them it, and trying to influence them, to go in this direction. Tree-based editors can be hard to implement, and can be confusing to users, so that's one reason GUIs tend to not attempt it, and just go with linear (although often nowadays "editable") chats.

Related to this I've learned that a lot of the time it's best to just use a "Context File" which is a big file of instructions explaining goals, architecture, and constraints so I can just tell the AI to read it and then say "Do Step 21 Now" for example, if step 21 is laid out in the file. This way I sort of can micromanage the context, rather than trying to reuse old discussions which are usually 90% throw away content, no longer appliable.