OpenAI launched its flagship model GPT-5. It was designed as a unified system combining a fast model, a deeper reasoning model (GPT-5 thinking), and a real-time router that chooses between them per query. OpenAI claimed state-of-the-art performance in coding, math, and health, along with reduced hallucinations. GPT-5 rolled out to all ChatGPT users including the free tier, marking the first major generational upgrade in roughly two and a half years since GPT-4.