Meet GPT-5.6 Sol, Terra, and Luna, OpenAI's new flagship lineup, and they launched under direct coordination with the US government before anyone outside ~20 partner orgs could touch them. - Sol is the flagship. Built for deep research, complex coding, and agentic work that runs for hours unsupervised. - Sol also has "Ultra Mode," which spins up multiple sub-agents working in parallel on the same task. - On cybersecurity benchmarks, Sol matches Anthropic's Mythos Preview using roughly a third of the output tokens. That's a real efficiency jump. - Terra is the mid tier. Performance close to GPT-5.5, at about half the price. - Luna is the speed and volume layer. Fast, cheap, built for high frequency lightweight tasks. - Here's the catch. None of this is publicly available yet. No waitlist, invite only, roughly 20 partner organizations. - This is reportedly the first US frontier model to launch under a government managed access list, which is a new thing in AI releases. - Broad access is "coming weeks" with no confirmed date. If you're building with AI right now, this is worth watching closely. Not just because of what these models can do, but because it might be a preview of how frontier AI gets released going forward, government checkpoint first, public access second. So I'm curious, if you had to pick your tier today, are you a Sol person running long agent workflows, a Terra person who just wants solid performance without burning budget, or a Luna person doing high volume lightweight stuff? As for me, I'll be with Terra. Link: https://openai.com/index/previewing-gpt-5-6-sol/