Claude: Speed up responses with fast mode. New "research preview" from Anthropic today: you can now access a faster version of their frontier model Claude Opus 4.6 by typing /fast in Claude Code... but at a cost that's 6x the normal price. Opus is usually $5/million input and $25/million output. The new fast mode is $30/million input and $150/million output! There's a 50% discount until the end of February 16th, so only a 3x multiple (!) before then. How much faster is it? The linked documentati...