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AnthropicClaude API
We've raised the max_tokens cap to 300k on the Message Batches API for Claude Opus 4.6 and Sonnet 4.6
AI summary
Written by AI from the official notes. Check them for exact details.The max_tokens cap for the Message Batches API has been increased to 300k for Claude Opus 4.6 and Sonnet 4.6.
- Max_tokens cap raised to 300k for Claude Opus 4.6 and Sonnet 4.6.
- Use
output-300k-2026-03-24beta header for longer outputs. - 1M token context window beta for older models will be retired on April 30, 2026.
- Migrate to Claude Sonnet 4.6 or Claude Opus 4.6 for 1M context window without beta header.
Why it matters: Users of Claude models should be aware of the new token limits and migration requirements for long-form tasks.
Full release notes2 changes
- We've raised the
max_tokenscap to 300k on the Message Batches API for Claude Opus 4.6 and Sonnet 4.6. Include theoutput-300k-2026-03-24beta header to generate longer single-turn outputs for long-form content, structured data, and large code generation tasks. - We're retiring the 1M token context window beta for Claude Sonnet 4.5 and Claude Sonnet 4 on April 30, 2026. After that date, the
context-1m-2025-08-07beta header will have no effect on these models, and requests that exceed the standard 200k-token context window will return an error. To continue using 1M context windows, migrate to Claude Sonnet 4.6 or Claude Opus 4.6, which support the full 1M token context window at standard pricing with no beta header required.