GPT-5.5 Instant: smarter, clearer, and more personalized

OpenAI has introduced GPT-5.5 Instant as the new default model for ChatGPT, designed to deliver more accurate, concise, and personalized responses. The model demonstrates significant improvements in factuality, reducing hallucinated claims by 52.5% in high-stakes domains like medicine and law compared to its predecessor. Key enhancements include better visual reasoning, improved STEM task performance, and more efficient use of historical context from past chats, files, and Gmail. Additionally, OpenAI is introducing 'memory sources,' which provide users with greater visibility and control over the data used to personalize their AI interactions.

(Source：OpenAI)