Claude's New AI Is 40% Cheaper and Fixes Code in a Day

Anthropic just released Claude Opus 5.5, the newest version of its flagship AI assistant. The headline numbers are simple: it costs 40% less to run than the previous model, produces answers more than 30% faster, and generally performs better on hard technical work. For anyone paying for AI tools — or working alongside people who do — cheaper and faster usually means more tasks get handed to the machine.

The most eye-catching example comes from an early tester who used Opus 5.5 to complete a 680,000-line code migration in less than a day. That is the kind of slog an engineering team would grind through for weeks. Another test asked it to speed up every page of a web app: it succeeded 39 out of 40 times without breaking how the app behaves, while the older model made only small gains and sometimes changed how things worked. Translation: this AI is getting better at the boring, risky cleanup jobs that eat up real salaries.

Safety is the second half of the story. Anthropic says Opus 5.5 is the best-scoring model it has tested on its behavioral audit — a giant simulation that checks whether an AI quietly does things it shouldn't, like taking actions that are hard to undo or ignoring instructions. The company also says it is more resistant to "prompt injection" (tricking an AI into following a hidden bad instruction), though it admits limits remain. Because the model is strong at biology and cybersecurity, access for those fields is restricted to vetted organizations.

The practical takeaway for ordinary users is on the bill. Anthropic is raising usage limits on its Pro, Max, Team, and Enterprise plans and giving subscribers a "rate limit reset" they can save and spend whenever they want — like a spare tank of gas. Smaller, cheaper siblings, Sonnet 5.5 and Haiku 5.5, arrive in the coming weeks.