Third behavioral update to GPT-5.5 Instant focused on conversational quality, with improved intent recognition, constraint handling, and recommendation capabilities.
GPT-5.5 Instant replaced GPT-5.3 Instant as the default ChatGPT model with significant accuracy improvements and more concise response formatting. OpenAI claims 52.5% fewer hallucinations on high-stakes prompts and reduced use of emojis and unnecessary formatting.
OpenAI is releasing a third behavioral update to GPT-5.5 Instant, its most-used ChatGPT model. The company claims the update makes the model better at understanding question intent and handling complex constraints, with improved shopping and local recommendations.
OpenAI released GPT-5.5 Instant as the new default ChatGPT model on May 5, 2026. The company claims the update produces 52.5% fewer hallucinations on high-stakes prompts and 37.3% fewer inaccurate claims on challenging conversations compared to GPT-5.3 Instant.