GPT-5.5 Instant Goes Live for All Users, Hallucination Rate Drops 52.5%; OpenAI Releases New Prompt Guide
OpenAI launches GPT-5.5 Instant to all users, cutting hallucinations by 52.5% in high-risk domains and boosting AIME math scores to 81.2. A new seven-section prompt structure guide emphasizes result-first logic and appropriate reasoning effort.








