On 26 June 2026, OpenAI announced three new models—GPT-5.6 Sol, Terra and Luna—in a limited preview for a small group of trusted partners and organisations, with access confined to approved use through the API, Codex or both, and ChatGPT excluded. Thirteen days later, on 9 July, OpenAI declared the GPT-5.6 family generally available across ChatGPT, Codex and the OpenAI API, and began a global rollout. The preview set standard API prices per million tokens: Sol at $5 input and $30 output, Terra at $2.50 and $15, and Luna at $1 and $6, which remained the same at general availability. Cached input is charged at one tenth of the normal input rate, and GPT-5.6 introduced paid cache writes at 1.25 times the uncached input rate, with explicit cache breakpoints and a 30-minute minimum cache life. For longer prompts, once input exceeds 272,000 tokens, the request is charged at twice the input rate and one and a half times the output rate for the whole request. The family supports a 1,050,000-token context window in the API, with up to 922,000 input tokens and 128,000 output tokens.