1M context is now generally available for Opus 4.6 and Sonnet 4.6 (https://claude.com/blog/1m-context-ga)

Here’s what surprised me:

Standard pricing now applies across the full 1M window for both models, with no long-context premium.

OpenAI and Gemini both charge more (https://www.llm-prices.com/#sel=gemini-3-1-pro-preview-200k%2Cgpt-5.4-272k%2Cgemini-3-1-pro-preview%2Cgpt-5.4) for prompts where the token count goes above a certain point - 200,000 for Gemini 3.1 Pro and 272,000 for GPT-5.4.

Tags: ai (https://simonwillison.net/tags/ai), generative-ai (https://simonwillison.net/tags/generative-ai), llms (https://simonwillison.net/tags/llms), anthropic (https://simonwillison.net/tags/anthropic), claude (https://simonwillison.net/tags/claude), llm-pricing (https://simonwillison.net/tags/llm-pricing), long-context (https://simonwillison.net/tags/long-context)