Opus 5.5 Prompting Guide

Start at medium effort, not high. It already beats Opus 5's high effort at lower cost. Stop telling it to "think carefully." Thinking is always on now, it decides that on its own. Don't treat a text reply as "task done." On long runs it gives progress updates mid-task, tell it to keep going. Mark pasted content separately (emails, docs, web text) so it knows what's your instruction and what's not. Skip the image tools you built earlier. It reads charts, screenshots, and diagrams accurately on its own now. Ban specific patterns for frontend work instead of saying "make it unique." It follows exact bans, not vague direction.