OpenAI cuts GPT-5.6 Luna price 80% after model optimizes itself

OpenAI cut GPT-5.6 Luna's price 80% to 20 cents per million input tokens and $1.20 per million output tokens, undercutting most open-source Chinese frontier models. GPT-5.6 Soul, running inside Codex, rewrote GPU kernels and improved speculative decoding, yielding 20% lower serving costs and 15% better token generation efficiency.