OpenAI launches GPT-5.6 with three tiers and Codex in ChatGPT

GPT-5.6 Sol sets a new SOTA on ARC-AGI-3 (7.8%) and on cybersecurity benchmarks. The model family includes three tiers (Sol, Terra, Luna) and Codex is now integrated into ChatGPT, enabling computer use and multi-step agentic tasks.