[gehsty]

I think this was more of a thing on older models. Since I started using Opus 4.5 I have not felt the need to do this.

[bavell]

Anthropic got rid of controlling the thinking budget by parsing your prompt - now it's a setting in /config.

[energy123]

They never parsed your prompt. The magic word reduces the probability that the token corresponding to the end of chain-of-thought will be emitted, which increases test-time compute.