OpenAI said Thursday it is cutting prices for two GPT-5.6 models after improving the efficiency of the systems that serve them. OpenAI is reducing prices just three weeks after introducing GPT-5.6. OpenAI claims it can now deliver substantially more intelligence per dollar through efficiency improvements. Cheaper Chinese open-weight models have also increased pressure on OpenAI and Anthropic to prove that their models justify their higher costs. OpenAI will lower the price of GPT-5.6 Luna — the fastest and lowest cost version of the new model — by roughly 80%. Luna will now cost 20 cents per million input tokens and $1.20 per million output tokens. OpenAI says it will reduce the price of GPT-5.6 Terra — the mid-range version — by 20%. Use of that version will now cost $2 per million input tokens and $12 per million output tokens. The most powerful version — GPT-5.6 Sol — won't see a price cut. OpenAI is in a heated battle with Anthropic and others for who can provide the best models, but lately customers seem much more interested in price. OpenAI and Anthropic have both adjusted pricing, rate limits and other usage policies as newer reasoning models consume far more tokens during longer-running agentic tasks.