OpenAI launches GPT-5.6, brings Codex into ChatGPT

GPT-5.6 Sol costs half the price and is twice as token efficient as its predecessor 'fable', and tops the DeepSWE leaderboard at 73%. Codex is now integrated into ChatGPT with new features including inline edits, PR reviews, and site publishing. Variants Sol, Terra, and Luna are available across platforms.