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

Luna drops to $0.20/M input and $1.20/M output tokens; Terra falls to $2/$12. GPT-5.6 Sol gains a Fast API mode at 2.5x speed for 2x price. OpenAI credits Sol's self-optimization — rewriting production kernels and improving speculative decoding — for cutting serving costs 20%.