OpenAI cut GPT-5.6 Luna pricing by 80% and Terra pricing by 20% while launching a Fast mode that makes Sol up to 2.5× faster. Starting July 30, GPT-5.6 Luna will cost 80% less while GPT-5.6 Terra will cost 20% less, according to an announcement from OpenAI. Pricing for GPT-5.6 Sol remains unchanged. OpenAI attributed part of the efficiency gains to work performed by GPT-5.6 Sol itself. Free and Go subscribers can access Terra in ChatGPT Work and Codex, while Plus, Pro, Business, and Enterprise subscribers can select Terra or Luna.