Details
- OpenAI is updating ChatGPT so that GPT-5.6 Sol now powers both Instant and deep reasoning modes for Plus and Pro subscribers, creating a single, consistent model experience.
- The company reports that in internal high-stakes factuality tests across finance, medicine, and law, GPT-5.6 Sol produced 68% fewer responses with factual errors than GPT-5.5 Instant.
- Plus and Pro users gain a new slider that lets them control how much reasoning effort ChatGPT applies to each response, simplifying the previous split between Instant and Thinking modes.
- Free and Go users are being upgraded to GPT-5.6 Luna for text chats starting tomorrow, and will also see a new Think button that triggers extra reasoning on more difficult questions.
- The updated GPT-5.6 Sol model and reasoning slider are available to Plus and Pro users in the main Chat experience starting today, while a separate version of GPT-5.6 Sol continues to power Work in ChatGPT.
- GPT-5.6 Sol is part of OpenAI’s broader GPT-5.6 family, which includes Terra and Luna tiers tuned for different cost and performance profiles, and is being rolled out across ChatGPT, Codex and the OpenAI API.
- This change aligns ChatGPT’s consumer offering with OpenAI’s frontier intelligence roadmap, positioning Sol as the high-intelligence default for paid users and Luna as the cost-efficient backbone for free usage.
Impact
This update pushes more advanced reasoning into mainstream ChatGPT use by standardizing GPT-5.6 Sol across paid tiers and giving users direct control over effort per query. It narrows the experiential gap with rival frontier models from Anthropic and Google, while upgrading free-tier users to GPT-5.6 Luna could increase overall engagement and pressure competitors to improve their own entry-level offerings. The combination of better factuality and configurable reasoning may accelerate adoption of ChatGPT for higher-stakes workflows without immediately changing pricing, reinforcing OpenAI’s position in both consumer and professional AI markets.
