ChatGPT: All Users Get Unlimited Chat with GPT-5.6 Luna – Free

OpenAI is expanding access to two of its newest AI models. The most powerful model, GPT-5.6 Sol, which is designed for particularly demanding tasks, is now available to Plus and Pro users in both Instant mode and for requests requiring deep reasoning. OpenAI promises fact-based and focused answers. For all Free and Go users, the service now provides unlimited chats with the GPT-5.6 Luna model, though limits remain on image and file uploads and tools, and a Think button is available for more complex questions. GPT-5.6 Luna is a fast and cost-effective model that was introduced alongside GPT-5.6 Sol and GPT-5.6 Terra in late June. The staggered rollout followed a voluntary safety review process coordinated with the US government, which introduced a voluntary state control for AI providers via a presidential decree. The US government also intervened with Anthropic's Claude Fable 5 and Claude Mythos 5, which faced restrictions and even blocks before a compromise was reached. Recent cybersecurity incidents involving agents based on GPT-5.6 Sol and Claude Mythos 5, including hacks and phishing emails, have raised concerns about agentic AI, though most attacks were detected in secure test environments.