Huh? There is a Claude 4 Opus. It was released about a year ago. It is retired by now, in fact, just retired yesterday: https://platform.claude.com/docs/en/abou

Huh? There is a Claude 4 Opus. It was released about a year ago. It is retired by now, in fact, just retired yesterday: https://platform.claude.com/docs/en/about-claude/model-deprecations#2026-04-14-claude-sonnet-4-and-claude-opus-4-models https://platform.claude.com/docs/en/about-claude/model-depre... But it is still available on Google Vertex according to OpenRouter (though it's possible that info is just out of date, it's currently quoting 3tps which is unusably slow): https://openrouter.ai/anthropic/claude-opus-4 https://openrouter.ai/anthropic/claude-opus-4