OpenAI cuts GPT-5.6 Luna price by 80%, Terra by 20%

GPT-5.6 Luna drops 80% to $0.20 per million input tokens and $1.20 per million output; Terra drops 20% to $2/$12. GPT-5.6 Sol gets Fast mode in the API, up to 2.5x speed at 2x price. OpenAI says GPT-5.6 Sol self-optimized its own serving, cutting costs by 20%.