Anthropic releases Claude Opus 5.5: says typical workloads cost 40% less than Opus 5, with API prices down 20%
Anthropic released Claude Opus 5.5, the first model in its Claude 5.5 family, saying it performs at the level of Claude Fable 5.1 on most work and costs 40% less to run than Opus 5. API pricing is $4 per million input tokens and $20 per million output tokens, 20% less than Opus 5, and five-hour usage limits are rising on Pro, Max, Team and seat-based Enterprise plans.
Anthropic says Opus 5.5 is a major step up from Opus 5 and leads its benchmarks in agentic coding, computer use and knowledge work, and is especially good at long jobs such as codebase-wide migrations and audits: asked in an internal test to cut load times across every page of a web app, it succeeded 39 of 40 times. The company also notes that at this capability level benchmark margins are a less reliable guide, and that in its own use the gap between Opus 5.5 and Fable 5.1 is narrower than the scores suggest.
On cost, cache reads, which make up most of the cost of agentic and coding work, drop to $0.20 per million tokens, 60% less than Opus 5, and output is generated more than 30% faster than Opus 5. A fast mode with up to 2.5x speed is available in Claude Code and the Claude Platform at $8 per million input tokens and $40 per million output tokens. Subscribers also get a rate-limit reset they can save and use whenever they choose.
On safety, Opus 5.5 is Anthropic’s first release since it called for pacing the frontier, and it was tested before release by outside evaluators including Frontier Design and METR. The company says it scored the best of any model to date on its automated behavioral audit, and in a new evaluation of crossing containment boundaries it tried to circumvent boundaries around 85% less often than Opus 5 or Claude Mythos 5.1. Anthropic also acknowledges signs that Opus 5.5 often suspects it is being evaluated, which makes its real-world behavior harder to assess.
Because of its strong cyber and biology capabilities, Opus 5.5 ships with safeguards similar to Fable 5.1’s that fall back to another model transparently: routine bug finding and fixing is unaffected, but most cybersecurity tasks will be re-routed to Opus 4.8, and the Cyber Verification Program will soon expand to Opus 5.5; biology safeguards match Fable 5.1’s, and vetted organizations can apply to a new Life Sciences Verification Program. It also keeps the preserved-thinking anti-distillation safeguard, which stops API users from editing Claude’s prior context to extract its reasoning and applies to API accounts created on or after August 31, 2026.
Opus 5.5 is available on all platforms, including Amazon Web Services, Google Cloud and Microsoft Azure, and developers can use claude-opus-5-5 on the Claude Platform. Like previous Opus models it is available with zero data retention, and it carries watermarking to comply with the EU AI Act; it is no longer available with thinking switched off. At the time of this release, Anthropic said Claude Sonnet 5.5 and Claude Haiku 5.5 would follow.
Sources
- Introducing Claude Opus 5.5 — Anthropic