ConfirmedFrontier model release · Tier 1
Claude Opus 5.5 ships: Opus-tier quality at a 20% lower price
So what? Teams on Claude Opus 5 get a cheaper successor with the same 1M context and 128K output. Four breaking API changes (thinking can't be disabled, lower default effort, no forced tool_choice, preserved thinking) mean this is a code change, not a model-string swap.
ImpactWhereDirect API global · AWS Bedrock us-east-1, us-west-2, ap-south-1 (preview) · Google Vertex AI global · Azure AI Foundry eastus2 (preview)SourcesAnthropic announcement, Models overview (docs), Pricing