> One of the most annoying things I've seen AI do is accidentally pull in old requirements and start building off of them.

This is actually the reason for me wanting to create what I call "Brain checkpoints". After chatting with the agent and letting it do its thing for discovery, I needed an easy way to understand what it knows at any given point. What files it has read, what tool calls were made and so forth.

Checkpoints work extremely well in Pi since you can create a branch, and have the agent generate a checkpoint based on what has changed since the last checkpoint and this information will not pollute the main conversation but you benefit from the token caching.