OpenAI ships GPT-5.5 Instant with 52.5% fewer hallucinations
openai released gpt-5.5 instant as the new default chatgpt model, claiming 52.5% fewer hallucinated claims on high-stakes medicine and law prompts versus gpt-5.3. it cuts inaccurate claims by 37.3% on flagged errors, offers tighter responses, and includes new memory source controls. gpt-5.3 instant remains available for three months.
OpenAI has designated GPT-5.5 Instant as the new default model for ChatGPT, succeeding GPT-5.3 Instant. The company reports that the new model reduces hallucinated claims by 52.5% on high-stakes prompts involving medicine, law, and finance, and decreases inaccurate claims by 37.3% in conversations users previously flagged for errors. The model also features tighter responses with fewer emojis and improved context awareness from sources like Gmail.
The rollout begins immediately for all ChatGPT users, though GPT-5.3 Instant will remain accessible for three months before retirement. Enhanced personalization features and a new 'memory sources' tool—which allows users to view, delete, or correct context used in responses—are launching first for Plus and Pro users on the web, with mobile and other tier support planned.