FWIW, in Claude Desktop you can edit previous user context and Claude will fork the conversation from that point. I know it's not quite what you as asking for,

FWIW, in Claude Desktop you can edit previous user context and Claude will fork the conversation from that point. I know it's not quite what you as asking for, but it's something. There are 3rd-party chat interfaces out there that have much better context controls if it matters enough for you that you're willing to resort to direct API usage.