Anthropic has launched Claude Opus 5.5, the first model in its new Claude 5.5 family, as the AI company continues to push toward models capable of handling longer and more complex tasks with greater efficiency.
Released on September 22, the model is designed particularly for agentic coding, computer use and knowledge work. Anthropic says Opus 5.5 performs at the level of its top-tier Claude Fable 5.1 on most work, while costing 40% less to run than the previous-generation Opus 5.
Cost efficiency is one of the key changes accompanying the launch.
Anthropic has priced Claude Opus 5.5 at $4 per million input tokens and $20 per million output tokens, compared with $5 and $25 respectively for Opus 5. The company says the model costs about 40% less to run on typical workloads, while generating output more than 30% faster.
Cache reads, which Anthropic says account for a significant share of costs in agentic and coding workloads, are priced at $0.20 per million tokens, compared with $0.50 for Opus 5.
The model has a 1-million-token context window and supports up to 128,000 output tokens, with adaptive thinking enabled by default.
Anthropic is positioning Opus 5.5 around tasks that require models to work through multiple steps rather than simply generate individual responses.
According to the company, an early tester used Opus 5.5 to complete a 680,000-line code migration in less than a day, work Anthropic says would previously have taken an engineering team weeks. Another tester used the model to audit and fix a 200,000-line codebase in under three hours.
The company also says Opus 5.5 delivered improvements on agentic coding benchmarks, including Terminal-Bench 4.0, FrontierCode and CursorBench. On Anthropic’s reported tests, the model outperformed Opus 5 across these evaluations.
Anthropic has also highlighted the model’s performance on broader knowledge-work tasks, while cautioning that benchmark differences at the current frontier may not always translate directly into equivalent differences in real-world use.
Anthropic has also said that Claude Sonnet 5.5 and Claude Haiku 5.5 are expected to follow in the coming weeks, extending the new 5.5 generation beyond its flagship Opus model.
