Claude Opus 4.1
RetiredAnthropic retired this model on 5 August 2026, so you can't start new chats with it. Use Claude Opus 4.5 instead. Your previous conversations are still available.
The oldest Opus here. Handles chat, code and reasoning, with the shortest context and output of the family.
- Best for
- Coding and deep reasoning
- Superseded by
- Claude Opus 4.5
Context window
200,000 tokens
≈ 150,000 words · about 600 pages
Max output
32,000 tokens
≈ 24,000 words in a single answer
Knowledge cutoff
January 2025
its training cutoff
Modalities
- TextInput and output
- ImageInput only
- AudioNot supported
- VideoNot supported
Features
- StreamingSupported
- Function callingSupported
- Structured outputsSupported
- Fine-tuningNot supported
Tools
- Web searchSupported
- Code interpreterNot supported
Ready to try it?
Polymeti is currently invite-only.
Log inBring your own API key · Your chats stay in your browser