For what it's worth, most people already are doing this! Some of the subagents in Claude Code (Explore, I think even compaction) default to Haiku and then you have to manually overwrite it with an env variable if you want to change it.

Imagine the quality of life upgrade of getting compaction down to a few second blip, or the "Explore" going 20 times faster! As these models get better, it will be super exciting!

> Imagine the quality of life upgrade of getting compaction down to a few second blip, or the "Explore" going 20 times faster! As these models get better, it will be super exciting!

I'm awaiting the day the small and fast models come anywhere close to acceptable quality, as of today, neither GPT5.3-codex-spark nor Haiku are very suitable for either compaction or similar tasks, as they'll miss so much considering they're quite a lot dumber.

Personally I do it the other way, the compaction done by the biggest model I can run, the planning as well, but then actually following the step-by-step "implement it" is done by a small model. It seemed to me like letting a smaller model do the compaction or writing overviews just makes things worse, even if they get a lot faster.