GPT-5.6: The System Card

While we wait for a general release, the system card is the best hint as to what is going on with the new candidate for America’s Next Top Model, GPT-5.6. This is only an Open AI model card, so by my standards it’s a light read. There’s a lot of things that you get in an Anthropic card, that are missing in an Open AI card. Overall, the card gives a clear and consistent impression that GPT-5.6-Sol is a substantial improvement over GPT-5.5, but still short of Mythos. Open AI calls it a ‘step function better’ than GPT-5.5. That seems accurate. OpenAI: Sol is our new flagship and a step function better than GPT-5.5. Terra delivers performance competitive to GPT-5.5 at 2x lower cost. Luna is our most cost-efficient model, delivering strong capability at our lowest cost. Together, the GPT-5.6 family gives people and developers more choice in how they balance intelligence, speed, and cost. Once available, pricing for GPT-5.6-Sol will be $5/$30, the same as GPT-5.5. Terra is $2.5/$15, Luna is $1/$6. They claim it will be on Cerebras at 750 TPS, which is insanely fast. Capacity will be limited, at least at first. They did not specify the price for that. There is a new higher thinking setting: Max. There is a new setting beyond Max called Ultra that lets GPT-5.6 spawn sub-agents. The intended strategy against bio and cyber misuse is defense-in-depth. My guess is that in practice this strategy is robust for now, but that the White House’s misunderstandings around Fable and what is and isn’t worrisome extend to Sol. No single safeguard is sufficient against determined or adaptive misuse. Across the GPT‑5.6 preview, we use layered safeguards, with exact configurations varying across models, and pressure-test them for real-world attacks. These include protections trained into the model, real-time checks during generation, account-level signals, differentiated access, monitoring, enforcement, and continued testing.​ … That is part of what the preview is designed to test. We want to u