OpenAI launches GPT-5.6 with Codex inside ChatGPT and major updates

GPT-5.6 launches with variants including Sol, Luna, Terra, and Ultra, and Codex is now integrated into ChatGPT. The Luna variant outperforms GPT-5.5 at top reasoning while costing 25x less, and Computer Use gains faster performance with Live Picture-in-Picture. Over 150 updates shipped in two months, reaching 7M+ weekly Codex users.