# Claude Code brings back the ultrathink keyword for extra reasoning

> Original title: 🌈 ultrathink 🌈

- Source: Ado Kukic
- Published: 2026-10-29T04:51:33.000Z
- Bad Influence: https://badinfluence.news/items/sexs540kwradya8tm8nf6dmfw
- Original: https://x.com/adocomplete/status/2115667836022772058

## Summary

Anthropic's Ado Kukic posts "ultrathink" with a rainbow emoji, and a quoted post from @dmwlff says ultrathink is back in the Claude Code CLI. The quoted author says the feature was turned off for a while because it might confuse users, and that they usually run Opus 5.5 on medium effort, using ultrathink on some turns for extra reasoning.

## Post

🌈 ultrathink 🌈

## Quoted post @dmwlff

> 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!

https://x.com/dmwlff/status/2115614417689944066