What Happened
On 2026-09-22, Anthropic released Claude Opus 5.5 as the first model in the Claude 5.5 family.
Why It Matters
The release pursued frontier-level professional capability at lower serving cost while strengthening behavioral evaluations and safeguards. The significance is not a standalone benchmark margin. More economical long-running work and stronger handling of task boundaries affect whether organizations can delegate multi-application jobs to agents and review useful results at practical cost.
Technical Details
Standard prices were $4 per million input tokens, $20 output, and $0.20 cache reads. Anthropic estimated typical workload costs 40% below Opus 5. Preserved thinking restricted editing of prior reasoning context for relevant newer API accounts; sensitive research had separate verification programs.