We've retired the Claude Opus 4.1 model (claude-opus-4-1-20250805).
We've retired the Claude Opus 4.1 model (claude-opus-4-1-20250805). All requests to this model will now return an error. We recommend upgrading to Claude Opus 5. Researchers can request ongoing access through the External Researcher Access Program.
출처: Claude Platform 릴리스 노트 (원문 보기)