Claude Opus 4.6

Claude Opus 4.6 is a large language model by Anthropic. It was released on Feb 5, 2026 along with several developer API updates including adaptive thinking support, effort levels, 1M token context (in beta),1 and the removal of assistant prefill.2

Technical details

Further reading

Footnotes

  1. Claude Opus 4.6 (Anthropic, Feb 5, 2026) 2

  2. Migration guide (Claude Platform Docs, retrieved July 3, 2026)