Anthropic Releases Claude Opus 5.5

Claude Opus 5.5 is Anthropic’s best performing model, but it also costs 40 percent less to operate than its predecessor, Claude Opus 5.

“Claude Opus 5.5 is our first release since we called for pacing the frontier,” the Anthropic announcement explains. “It was tested before release by external evaluators, including Frontier Design and METR. On our automated behavioral audit, the most comprehensive alignment test we run, Opus 5.5 is the strongest-performing model we’ve tested to date. It also comes with the safeguards we’ve developed for our most capable models.”

According to Anthropic, Claude Opus 5.5 performs at a level similar to the mythical Claude Fable 5.1 “on most work,” and it’s particularly good at finding deficiencies in software. It’s also the safest model that the company has released based on the scores it obtained its automated behavioral audit. And it’s being deployed with safeguards similar to those on Claude Fable 5.1.

Claude Opus 5.5 also communicates more clearly than its predecessor, answering what Anthropic says was “common feedback” about Opus 5. Because it requires less compute to serve than Opus 5, it’s input and output token costs are 20 percent lower. And Anthropic is increasing the five-hour usage limits on Pro, Max, and Team plans and letting subscription users a rate limit reset whenever needed.

Claude Opus 5.5 is now available on all platforms, including Amazon Web Services, Google Cloud, and Microsoft Azure. And Anthropic says that this is just the first release in the 5.5 wave and that we can expect to see Claude Sonnet 5.5 and Claude Haiku 5.5 releases soon.