Maybe somebody can enlighten me... this page for ctx says the program saves all "decisions, constraints, intent, rejected approaches, bug investigations, refactors, file paths, commands, patches, and notes from previous agents."

What am I missing if I instead just instruct the agent to create a handful of files called something like HISTORY.md and tell it to log summarized versions of all of these things inside the project repo whenever something is changed or evaluated? (Which is very close to what I currently do.)

It deterministically pulls the full session log so you don't need to tell an LLM to do it, plus it doesn't pollute your repo with such files.