RTK which I guess is a close equivalent.
Headroom which is complementary.
https://github.com/chopratejas/headroom
I have tried both of these and I have to say, I didn't notice any difference. That's not to say there wasn't a difference (rtk logs were telling me enthusiastically how many tokens I'd saved), it's just that pretty much all context is coming from reading data from files and neither of these tools can do anything about that.
As I switched from Claude Code to Pi recently, and tweaked my workflow, I've seen a much bigger/more obvious reduction in context use from that and I don't use either of these tools right now.
I'm open to trying them again though, has anyone had a different experience than mine?