Claude Opus 4.1 Is Now Fully Retired — Requests to claude-opus-4-1-20250805 Return an Error
Anthropic Claude Platform release notes·medium signal
The August 5 platform release notes confirm the model is no longer served at all: all requests error out, with Anthropic recommending Opus 5 and pointing researchers to the External Researcher Access Program for continued access. Anyone with a pinned model ID in production config or eval harnesses breaks today rather than degrading gracefully. Worth auditing any repo that hardcoded the 2025-08-05 snapshot string.