1M context is now generally available for Opus 4.6 and Sonnet 4.6

Simon Willison’s Weblog Subscribe Sponsored by: CodeRabbit — Planner helps 10x your coding agents while minimizing rework and AI slop. Try Now. 1M context is now generally available for Opus 4.6 and Sonnet 4.6. 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 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. Posted 13th March 2026 at 6:29 pm Recent articles My fireside chat about agentic engineering at the Pragmatic Summit - 14th March 2026 Perhaps not Boring Technology after all - 9th March 2026 Can coding agents relicense open source through a “clean room” implementation of code? - 5th March 2026 This is a link post by Simon Willison, posted on 13th March 2026. ai 1913 generative-ai 1696 llms 1662 anthropic 265 claude 261 llm-pricing 66 long-context 20 Monthly briefing Sponsor me for $10/month and get a curated email digest of the month's most important LLM developments. Pay me to send you less! Sponsor & subscribe Disclosures Colophon © 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014 2015 2016 2017 2018 2019 2020 2021 2022 2023 2024 2025 2026