Anthropic releases flagship language model Claude Opus 5.5

According to the developer, the model generates responses more than 30% faster than its predecessor Opus 5 and is on average 40% cheaper on standard tasks. Base API pricing stands at $4 per 1 million input tokens and $20 per 1 million output tokens compared to the previous $5 and $25 respectively, while cache reads have fallen from $0.50 to $0.20.

The developer is targeting the new model at long-running engineering and analytical tasks. According to company claims, during preliminary testing the model completed a code migration on a 680,000-line software project in less than 24 hours, and checked and fixed a 200,000-line database in less than three hours, whereas Opus 5 took more than 20 hours to do so. In the Terminal-Bench 4.0 benchmark, the model scored 66.4%.

Claude Opus 5.5 is already available to users of the Claude API, the Claude Platform, as well as via AWS, Google Cloud, and Microsoft Azure cloud services. For high-speed generation, a Fast Mode has been launched at an increased cost of $8 per million input tokens and $40 per million output tokens.