Claude Opus 5.5 Tested: What’s New and How Good is it?

What happens when an AI model gets better at reasoning, faster at responding, and cheaper to run at the same time? That is the promise behind Claude Opus 5.5, Anthropic’s latest flagship model and the first release in the Claude 5.5 family. Opus 5.5 brings several notable changes. It now reasons on every request, generates responses more than 30% faster compared to Opus 5, costs less per token, and is designed to produce clearer, more focused writing. Anthropic also says it can complete many tasks using fewer tokens, bringing the total cost of typical workloads down by around 40%. For developers, these changes could mean faster coding and more efficient AI applications. For businesses, they could make it more practical to use advanced AI across everyday workflows without letting costs grow too quickly. But how much of an improvement is Opus 5.5 in practice? In this article, we’ll look at what’s new, break down the published benchmarks, unpack the important details behind the cost and performance claims, and walk through three simple tests you can run…