The move
On August 11, 2026, Anthropic announced that Claude Sonnet 5's introductory pricing of $2 per million input tokens and $10 per million output tokens is now permanent, canceling the increase to standard Sonnet rates that had been scheduled for September 1, 2026.
The SPP read
Anthropic made Claude Sonnet 5's introductory rate of $2 per million input tokens and $10 per million output permanent on August 10, withdrawing the standard $3/$15 pricing scheduled for September 1. No existing invoice moves; what moved is the effective date: a planned 50% step-up canceled three weeks before it took effect. Holding the introductory price protects the displacement math Sonnet 5 was priced for.