For every prompt and response, I extract each semantic statement. Map its reasons in a Whybase proposition tree -- a recursive proposition tree where each atomic statement is proposition with one or more premises (atomic statements, which also stand alone as propositions). Then I map each statement to the relevant code, hinted at by tool calls and git commits. Every time an agent touches that file or directory, a hook triggers in Claude Code that queries the codegraph db for the mapped statements. This helps the agent remember something I said in June when it revisits the code in July.

What if the June conversation is outdated and is no longer applicable by July? Do you have a mechanism for dropping older, subsumed propositions in your database?

Github Copilot had the idea of attaching memory to files, and if the file hash changes the memory is automatically dropped (not sure if they still do it). This means they are overly eager to drop stuff (even if the file change is just cosmetic), but at least they don't accumulate outdated cruft too much. (a memory can still be outdated if it was invalidated by a change in another file though)