Anthropic released Claude Opus 5.5 on September 22, 2026, with lower standard API prices and a focus on extended coding and knowledge-work tasks. The release is drawing attention for its cost claims as well as changes developers must account for when upgrading.
What changed in pricing
The launch announcement lists US$4 per million input tokens and US$20 per million output tokens, 20% below Opus 5. Cache reads cost US$0.20 per million tokens.
Anthropic also claims a 40% reduction in typical workload costs at default settings, reflecting more than the headline token-price reduction. That is a vendor test result; actual bills depend on usage, caching, task length and configuration.
An upgrade with compatibility changes
The model documentation lists a one-million-token context window and a standard maximum output of 128,000 tokens. Adaptive thinking is always enabled.
Developers should review the migration guidance before changing model identifiers. The documentation flags changes to forced tool use, thinking-block handling and support for an older computer-use tool. It also notes that applications displaying progress between tool calls may need to adjust how they request and render thinking content.
Cloud access
AWS confirms availability through Amazon Bedrock and Claude Platform on AWS. The former offers AWS-managed capabilities, while the latter exposes Anthropic’s native platform experience with AWS billing and authentication. Regional availability and the chosen service’s terms remain relevant to deployment decisions.
Featured image: AI-generated conceptual illustration.
