I built a memory tool about 6 months while playing with MCP, it was based on a SQLite db. My experience then was that Claude wasn't very good at using the tools. Even with instructions to be proactive about searching memory and saving new memories it would rarely do so. Once you did press it to be sure to save memories it would go overboard, basically saving every message in the conversation as a memory. Are seeing more success in getting natural and seamless usage of the memory tools?
IIRC at the time I was testing with Sonnet 3.7, I haven't tried it on the newer models.
It is really weird how some sessions with claude are better than others despite similar tasks. I'm certain it's not sleep deprivation or something else. Sometimes it gets on a hot streak by accidentally discovering the right tools to use. It's like an unstable solder joint or something. It's very difficult to guide it. When you do it overfits hard.