OpenAI Launches GPT-6 Sol and Luna Minutes After Anthropic Drops Claude Opus 5.5

In brief

• OpenAI released GPT-6 Sol and GPT-6 Luna on Tuesday, cutting their API prices in half versus GPT-5.6's promotional rates.
• The release happened minutes after Anthropic launched Claude Opus 5.5.
• OpenAI says its internal coding-deception rate fell to 1.3% for Sol and 2.8% for Luna, both far below GPT-5.6 Sol's 10.4%.

OpenAI released two new models, GPT-6 Sol and GPT-6 Luna, on Tuesday. It happened minutes after Anthropic launched Claude Opus 5.5, its own new flagship.

Sol and Luna sit below GPT-6 Astra, the model OpenAI called "the most intelligent and aligned model in the world" when it launched on September 3. Astra is still OpenAI's top pick for the hardest jobs; Sol and Luna are the cheaper, faster options built for everyday work.

So it’s very similar to the same strategy Anthropic has applied. Astra being the equivalent to Fable, Sol being the equivalent to Opus, Terra being the equivalent to Sonnet, and Luna being the equivalent to Haiku (when it’s upgraded).

OpenAI also tweaked the price to remain competitive. The API costs for both models was reduced by 50% compared to GPT-5.6's promotional rates per token. Tokens are the chunks of text a model reads and writes, usually a bit less than a full word, and companies pay by the million because that's how AI bills add up at scale.