Does this look okay? Should I try to get it done for 2.0?

I don't see the need for improvement. I consider it a fairly low-level API, so having bit masks is fine: users dealing with this settings should know what a bit mask is. As for the naming of the specific flags: So far, all of them are for debugging, as would be the proposed DEBUG_SAVEALL. You also have set/get_threshold, which clearly controls a different kind of setting. Unless you come up with ten or so additional settings that *must* be there, I don't see the need for generalizing the API. Why is gc.set_option(gc.THRESHOLD, 1000, 100, 10) so much better than gc.set_threshold(1000, 100, 10) ??? Even if you find the need for a better API, it should be possible to support the current one for a couple more years, no? Martin