Anthropic has locked Claude Sonnet 5.5 output pricing at $10 per million tokens after making the model's July 2026 introductory $2/$10 rate permanent instead of allowing a scheduled rise to $3/$15. This break from the prior $3/$15 Sonnet anchor across multiple generations reflects competitive pressure from OpenAI and others while delivering stronger agentic performance at lower effective cost. A further October 7 cache-read cut to $0.10 per million tokens reduced agentic workloads by roughly 20 percent without altering base output rates. Traders are watching for new model releases, additional caching or batch optimizations, and any response to rival pricing moves that could push the 2026 output token price lower or stabilize it near current levels through year-end.