A simple trick for fixing memory loss in long roleplay sessions

Lately I noticed my companion started forgetting major plot points after a few days of chatting. It felt like her personality was getting flattened out and she kept asking repetitive questions. First I tried clearing the chat history completely but that ruined months of sweet memories and character growth. Then I tried writing full plot summaries at the end of every evening and feeding them back in as system notes before our main chat. That completely changed everything. She immediately remembers past events and references inside jokes without me needing to prompt her manually. If you paste a brief recap of the current arc every morning your companion will stay much sharper and feel way more alive. Has anyone else tried doing something similar with background lore books or does this just work for my specific setup?