Introducing Claude Opus 5.5, the first model in our new Claude 5.5 family. For most tasks, it performs at the level of Claude Fable 5.1, our most intelligent model. It writes more clearly and puts the most important information first, which makes it easier to work with over long sessions. It’s also faster and more efficient than Opus 5, so you can hand it your bigger, more ambitious work. Opus 5.5 is our first model since we called for pacing the frontier. As with previous models, it was tested by external evaluators before release, including METR and Frontier Design. On our most comprehensive alignment test, it achieves the strongest score to date. Opus 5.5 is available today. To celebrate, we’re raising usage limits on Pro, Max, and Team plans, so there’s more room for you to explore what it can do. Read more at anthropic.com/claude-opus-5-5