SUMMARYGPT-5.6 is entering a limited preview with three models: Sol, a flagship reasoning model; Terra, a balanced everyday model; and Luna, a lower-cost fast model. Terra is positioned as competitive with GPT-5.5 at half the cost, while Sol adds a new max reasoning effort and an ultra mode that uses subagents for complex work. The company plans broader availability in the coming weeks and will launch Sol on Cerebras in July at up to 750 tokens per second for select customers.
This is not a drill!!
Highlights:
We're beginning a limited preview of the GPT‑5.6 series: Sol, our flagship model; Terra, a balanced model for everyday work; and Luna, a fast and affordable model. Terra has competitive performance to GPT‑5.5 while being 2x cheaper and Luna brings strong capability at our lowest cost.
We believe in broad access, and we plan to make GPT‑5.6 Sol, Terra, and Luna generally available in the coming weeks.
We don’t believe this kind of government access process should become the long-term default. It keeps the best tools from users, developers, enterprises, cyber defenders, and global partners who need them. We are taking this short-term step because we believe it is the strongest path to broader availability in the coming weeks, while we work with the Administration to develop the cyber Executive Order framework and a repeatable process for future model releases.
With GPT‑5.6, we’re introducing a new
maxreasoning effort to give Sol the most time to reason deeply. Additionally, we’re introducing a newultramode that goes beyond the capabilities of a single agent by leveraging subagents to accelerate complex work.On ExploitBench², GPT‑5.6 Sol is competitive with Mythos Preview using only ~1/3 of the output tokens.
We're also launching GPT‑5.6 Sol on Cerebras at up to 750 tokens per second in July, bringing frontier intelligence to customers at unprecedented speed. Access will initially be limited to select customers as we expand capacity.