Improving GPT‑5.6 Sol in ChatGPT—and expanding access to GPT-5.6 Luna for free users
OpenAI updates ChatGPT with improved GPT‑5.6 Sol for Plus/Pro users and expands free access to GPT‑5.6 Luna, introducing a Think button and reasoning slider.
OpenAI announced updates to ChatGPT, enhancing GPT‑5.6 Sol for Plus and Pro users to deliver more reliable, focused answers with tighter formatting and fewer errors. The model now adapts its detail level based on the question, avoiding unnecessary information while maintaining accuracy. A new slider allows users to adjust the reasoning effort for each response, balancing speed and depth as needed.
Free users will now default to GPT‑5.6 Luna with unlimited text chats, while a new Think button enables deeper reasoning for complex questions. The updates aim to provide consistent experiences across Instant and Thinking modes, ensuring smoother transitions between quick answers and detailed responses without tonal shifts.
GPT‑5.6 Sol was tested on financial, medical, and legal prompts, reducing factual errors by 62% with Luna and 68% with Sol compared to GPT‑5.5 Instant. The model improves handling of dates, numbers, and sources, minimizing mistakes in factual-dependent answers. Users can now rely on more precise responses for planning, research, or decision-making tasks.
The changes take effect today for Plus and Pro users, who can access the updated GPT‑5.6 Sol and reasoning slider across web, mobile, and desktop platforms. Free users gain unlimited text chats with GPT‑5.6 Luna and the option to engage deeper reasoning via the Think button for more demanding queries.