OpenAI launches GPT-5.6 Sol/Terra/Luna and merges Codex into ChatGPT superapp

[AINews] OpenAI launches GPT 5.6 Sol/Terra/Luna, Codex becomes ChatGPT superapp

OpenAI dropped GPT-5.6 in three sizes—Sol, Terra, Luna—on July 10. Sol hits 53.6 on Agents' Last Exam, beating Claude Fable 5 by 13.1 points at roughly one-quarter the cost. API pricing starts at $5/$30 per million input/output tokens for Sol, with cheaper tiers below. Codex desktop merges into ChatGPT alongside ChatGPT Work, Sites beta, and a multi-agent beta; the new 'ultra' effort level runs four agents in parallel by default. Meta launched Muse Spark 1.1 the same day but got overshadowed.

Why it matters: A mainline OpenAI version bump with a flagship model that leads Claude Fable 5 by 13+ points on a key agent benchmark at aggressive pricing, plus Codex folding into ChatGPT as a superapp. Cross-source cluster event, all three HKR axes hit. The post doesn't disclose Sol's param...