I have experimented with telling Claude Code to keep a historical record of the work it is performing. It did work (though I didn't assess the accuracy of the record) but I decided it was a waste of tokens and now direct it to analyze the history in ~/.claude when necessary. The real problem I was solving was making sure it didn't leave work unfinished between autocompacts (eg crucial parts of the work weren't performed and instead there are only TODO comments). But I ended up solving that with better instructions about how to break down the plan into bite-sized units that are more friendly to the todo list tool.

I have prompting in AGENTS.md that instructs the agent to update the relevant parts of the project documentation for a given change. The project has a spec, and as features get added or reworked the spec gets updated. If you commit after each session then the git history of the spec captures how the design evolves. I do read the spec, and the errors I've seen so far are pretty minor.