Anthropic Launches Claude Opus 5.5 With Lower Prices and Faster Output

Claude Opus 5.5 is now available as the first model in a new 5.5 family that performs at the level of Claude Fable 5.1 on most work while costing 40% less to run than Opus 5 at default settings on typical workloads, according to Anthropic.

Opus 5.5 leads in agentic coding at 66.4% on Terminal-Bench 4.0, compared with 55.8% for Fable 5.1, alongside gains in computer use and knowledge work. In early testing, one user completed a 680,000-line code migration in less than a day, work the company says would have taken an engineering team weeks. In an internal test translating HAProxy from C to Rust, both rewrites passed nearly all regression tests, with Opus 5.5 finishing in 9.5 hours versus 12 for Fable 5.1 at 51% lower cost. Benchmark margins have become a less reliable guide at these levels, the company notes, with the gap narrower than scores suggest in its own use.

Input and output tokens are priced at $4 and $20 per million. Cache reads, which account for most agentic coding costs, fall to $0.20 per million, while output arrives more than 30% faster than Opus 5. Five-hour usage limits on Pro, Max and Team plans increase as well, with subscribers getting a rate-limit reset they can save for later.

On safety, the model posts the company's best scores to date on its automated behavioral audit across nearly 2,000 scenarios, with fewer hard-to-reverse actions and stronger resistance to prompt injection. Because capabilities in biology and cybersecurity are comparable to Mythos 5.1, it ships with Fable 5.1-class safeguards that reroute most cyber tasks to Opus 4.8, while vetted organizations can apply for Life Sciences access now with expanded Cyber Verification access to follow. External checks before release included Frontier Design and METR.

The update follows the Opus 5 launch in July 2026, which positioned the model near Fable-level intelligence at half the price. It also follows the Fable 5.1 release in September 2026, which cut effective costs for agentic work through cheaper cache reads.

Developers can access the model now on all platforms, including Amazon Web Services, Google Cloud and Microsoft Azure, using the claude-opus-5-5 identifier. Fast mode runs at up to 2.5x speed for $8 and $40 per million input and output tokens. Sonnet 5.5 and Haiku 5.5 are expected in the coming weeks with many of the same efficiency, performance and safety improvements.