OpenAI slashes GPT-5.6 Luna price by 80%

OpenAI cut GPT-5.6 Luna API prices by 80% to $0.20 per million input tokens and $1.20 per million output, and GPT-5.6 Terra by 20% to $2/$12. GPT-5.6 Sol gets a Fast mode in the API, up to 2.5x speed for 2x price. The cuts follow Chinese AI competition and make Luna cheaper than Gemini 3.1 Flash-Lite.