OpenAI brings GPT-6 Sol and Luna to everyday AI work

OpenAI has introduced GPT-6 Sol and GPT-6 Luna as faster, lower-cost additions to the GPT-6 family. The company says the models bring improvements in coding, computer use, factuality, and professional work to tasks that do not need the full depth of Astra.

Both models are available through the API and Codex. OpenAI says their API prices are 50% lower than the promotional prices of their GPT-5.6 counterparts, while improved prompt caching can further reduce the cost of repeated context in long-running agents.

Two different jobs, one release

OpenAI positions Sol for complex coding and agent workflows and Luna for focused, high-volume work. The model pages list standard prices of $2 input and $10 output per million tokens for Sol, versus $0.10 input and $0.50 output for Luna. Both list a 1.05-million-token context window, but a larger window does not make a poorly scoped task cheaper or more reliable.

The launch article reports improvements on coding and agent evaluations and compares cost per task with rival models. Those benchmark comparisons come from OpenAI; they are useful directional evidence, not a substitute for testing your own prompts, tools, latency, and failure cases. The API changelog confirms the model IDs and availability in the Responses and Chat Completions APIs.

What I would benchmark

Run the same real task set through both models. Track finished-task quality, retries, tool calls, wall time, and total bill, not only token price. A cheap call that needs five retries can be the expensive choice. Sol may make sense for ambiguous, multi-step work; Luna may win when the task is narrow and repeated at scale. The right answer is in your workload, not in the model name.

Sources and further reading

• Original publication
• OpenAI API: GPT-6 Sol model details
• OpenAI API: GPT-6 Luna model details
• OpenAI API changelog