The article provides guidance on prompting Claude Opus 5.5, a model that generates output tokens 30% faster than its predecessor, Claude Opus 5. Existing prompts for Claude Opus 5 should still work well, but the new model introduces some changes, including four breaking API changes that require migration. The key control for prompting Claude Opus 5.5 is "effort", which determines how much the model thinks, and users can adjust this setting to trade off between intelligence, latency, and cost. The article offers a guide for prompting patterns specific to Claude Opus 5.5, as well as links to additional resources for understanding the model's capabilities and best practices for prompting.