This guide covers prompting patterns for Claude Opus 5.5, which generates output tokens 30% faster than Claude Opus 5 while using fewer tokens for the same tasks. The document provides specific guidance for different use cases—from calibrating effort levels and handling agentic workflows to improving visual input processing and multiagent coordination. Key capabilities include stronger performance on multistep coding tasks, knowledge work with fewer factual errors, clearer communication of work progress, and more accurate reading of visual material.