Anthropic announced that the 1M token context window is now generally available at standard pricing for Claude Opus 4.6 and Sonnet 4.6 — no beta header, no surcharge, no special configuration. What was previously a premium feature requiring the context-1m-2025-08-07 beta header is now the default for the latest models.
The pricing change is significant. Previously, requests using the extended context window carried a surcharge that made long-context workloads substantially more expensive. By eliminating the premium entirely, Anthropic is signalling that million-token context is no longer an experimental feature — it is the standard operating mode for serious agentic development. For Claude Code users working with large codebases, this means full-repository analysis in a single session at no extra cost.
Developers using older models need to act before the deadline. The 1M token context beta for Claude Sonnet 4.5 and Claude Sonnet 4 will be retired on 30 April 2026. After that date, the beta header will have no effect on those models, and requests exceeding the standard 200K token window will return errors. Migration to Sonnet 4.6 or Opus 4.6 is straightforward — both models are drop-in replacements with improved performance across all benchmarks.
For context engineers building production workflows, this is a clear signal to standardise on the 4.6 model family. The combination of million-token context at standard pricing, improved agentic capabilities, and the recent GA of adaptive thinking makes Opus 4.6 and Sonnet 4.6 the obvious choices for any new Claude Code integration.
