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We've retired the 1M token context window beta for Claude Sonnet 4.5 and Claude Sonnet 4
AI summary
Written by AI from the official notes. Check them for exact details.The 1M token context window beta for Claude Sonnet 4.5 and Claude Sonnet 4 has been retired.
- 1M token context window beta retired for Claude Sonnet 4.5 and 4.
- Requests over 200k tokens now return an error.
- Migrate to Claude Sonnet 4.6 or Claude Opus 4.6 for 1M context window.
Why it matters: Users of Claude Sonnet 4.5 and 4 should upgrade to access larger context windows.
Full release notes
- We've retired the 1M token context window beta (
context-1m-2025-08-07) for Claude Sonnet 4.5 and Claude Sonnet 4. The beta header now has no effect on these models, and requests exceeding the standard 200k-token context window return an error. To use the 1M context window, migrate to Claude Sonnet 4.6 or Claude Opus 4.6, where it's included at standard pricing with no beta header required.