1M Context Window Claude Opus 4.6 and Sonnet 4.6 support 1M token context with the beta header. Use it well or burn money for nothing. When to Use - You have a codebase, book, log bundle, or document set that fits in 1M tokens - You need cross-document reasoning that chunked RAG can't deliver - You're deciding between 1M-context vs a RAG pipeline - You want to cache a giant system prompt / knowledge base across requests Enabling 1M Context Without the beta header, requests over 200K tokens will error. Pricing Tiers Long context is priced differently above 200K input tokens. Check your provide…