I suffered this same problem with Anthropic, ironically. Mainly with reverse engineering things. That would usually end up requiring a ton of context it had to remember, and then compaction would kick in and it would just forget half of it (that half being really important too), and even switching to Claude Code and having it document everything wouldn't really fix the problem. It was honestly quite sad because I've usually gotten better results with it, but it falls a part the moment you try doing something like that that's really complicated and requires a ton of different attempts to get it right.