ultrathink is back in the CC CLI.
We turned this off for a while because it's weird and maybe confusing.
But I like weird, and I don't think it's that confusing.
I mostly run Opus 5.5 on medium. Some turns, though, I want to put a little extra mustard on it. ultrathink!
It seems like a century ago in AI time, but last fall I gave a talk about some of the early design decisions and mistakes I made in Claude Code. Some of the points here are already a little dated (like opening your editor!) but hopefully still entertaining.