effort-levels

2 questions

AI

How do I control how much Claude thinks before it answers?

Effort levels and extended thinking are two separate controls on top of model selection. Opus 4.7 adds xhigh and adaptive reasoning; /effort sets the default for a session; Option+T shows thinking in real time. The ultrathink keyword triggers one-off max thinking.
AI

Which Claude model and effort level should I use in Claude Code?

Default to Opus 4.7 at xhigh effort. Drop to Sonnet for routine work, raise to max only when xhigh hits a wall, and never switch mid-session unless you mean to pay for it.