GPT 5.6: OpenAI Tests Next AI Model in ChatGPT

OpenAI's next AI model, GPT 5.6, is reportedly being tested inside ChatGPT for select Pro subscribers. There's a rumored launch between June 22nd and 28th, 2026. Prediction market Polymarket shows a 90% probability for a late June release, with nearly a million dollars in bets placed on this timeline. Rumored features for GPT 5.6 include a 1.5 million token context window, improved agentic coding, and stronger UI generation. OpenAI's chief scientist has described it as a meaningful improvement over GPT-5.5. Users are reporting sharper responses and longer processing times in ChatGPT, fueling speculation about this quiet testing. This model arrives as OpenAI prepares for a potential one trillion dollar IPO and faces increased competition. This development could significantly impact how we interact with AI.