“GPT-5.6: The System Card” by Zvi

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 OpenAI 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 OpenAI 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.

OpenAI 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. [...]

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Outline:

(03:49) What's In A Name?

(04:26) Fix This Code

(07:08) Crossover Event Requested

(07:43) Disallowed Content (3)

(09:03) Avoiding Accidental Data-Destructive Actions (3.3)

(09:29) Are You Sure? (3.4)

(09:58) Jailbreaks (4.1)

(10:14) Prompt Injection (4.2)

(10:40) HealthBench (5.1)

(11:00) Dynamic Mental Health Adversarial User Simulations (5.2)

(12:21) Hallucinations (6)

(12:50) Isolated Misaligned Actions (7.1)

(13:10) Going Overboard (7.2)

(18:11) Chain of Thought Evaluations (7.3)

(19:18) Bias (8)

(19:27) Preparedness (9)

(20:15) Biological Risks (9.1.1)

(22:15) Cybersecurity (9.1.2)

(28:40) External Cyber Evaluation FrontierCyber from Irregular (9.1.2.5)

(30:32) Cyber Conclusions

(31:07) Recursive Self-Improvement (9.1.3)

(32:22) METR Warns Us (9.1.3.6)

(35:04) Everything Is Under Control

(37:44) Metagaming (7.4)

(40:17) Apollo Research and Sandbagging

(43:09) Safeguards (9.3)

(50:01) Better Not Call Sol Yet

The original text contained 2 footnotes which were omitted from this narration.

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First published:
June 28th, 2026

Source:
https://www.lesswrong.com/posts/JFjNmPTbH8kL6xtp6/gpt-5-6-the-system-card

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Narrated by TYPE III AUDIO.

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