OpenAI launches GPT-5.5 Instant as ChatGPT's new default model, cutting hallucinations by 52.5%
OpenAI rolled out GPT-5.5 Instant as ChatGPT's new default model, claiming it reduces hallucinations by 52.5% on high-stakes prompts in medicine, law, and finance. The update delivers shorter, clearer responses while introducing a memory sources feature that shows users exactly what context informed their answers. Enhanced personalization pulls from past chats and connected services.