Anthropic introduces Claude Opus 5.5

Anthropic introduced Claude Opus 5.5, the first model in the Claude 5.5 family. It performs at the level of Claude Fable 5.1 on most work and costs 40% less to run than Opus 5, marking the first release since Anthropic’s call to pace the frontier.

What’s actually new

• Big performance jump. Early testers saw large gains on complex work: one completed a 680,000-line code migration in less than a day. On FrontierCode, Opus 5.5 at default effort beats GPT-6 Astra’s top score at about a fifth of the cost per task.
• Lower prices. Input and output tokens are $4 and $20 per million, 20% less than Opus 5, and cache reads drop to $0.20 per million, 60% less. Output also comes more than 30% faster.
• Safety ahead of the curve. Opus 5.5 is the strongest-performing model Anthropic has tested on its automated behavioral audit, with better resistance to prompt injection and to crossing containment boundaries. It launches with Fable 5.1-level safeguards on cybersecurity, biology, and distillation.

Why it matters

Opus 5.5 delivers frontier results in agentic coding, computer use, and knowledge work while sharply cutting token costs, especially for the cache-heavy workloads agents generate. Tested before release by external evaluators including Frontier Design and METR, it offers teams a more affordable path to autonomous, long-running work without giving up safety.

(Original source: Anthropic)