OpenAI drops GPT-6 Sol at half Opus 5.5's price, 90 min later

OpenAI released GPT-6 Sol and GPT-6 Luna just 90 minutes after Anthropic shipped Claude Opus 5.5. Sol costs $2/$10 per million input/output tokens, half the price of Opus 5.5 ($4/$20). Luna costs $0.10/$0.50. Both are 50% cheaper than their GPT-5.6 versions, and OpenAI told VentureBeat these are permanent prices, not a launch promo.

Both sit below GPT-6 Astra, the flagship OpenAI released on Sept 3. Sol is built for complex coding and agent work. Luna is the cheap, fast option for high-volume tasks. OpenAI says Sol makes about half as many factual mistakes as its predecessor. On the AutomationBench business-workflow test, Sol scored 33.2% at $0.27 per task, against 26.9% for Claude Opus 5 at max effort, which cost 11x as much per task. The catch is that Opus 5 was replaced hours earlier, and nobody has run Sol against Opus 5.5 in the same test setup yet.

Anthropic's own launch cut prices too: Opus 5.5 is 20% cheaper than Opus 5, and Anthropic says it matches Fable 5.1 on most tasks. Sol and Luna are rolling out now in ChatGPT Work, Codex and the API. Luna also reaches Free and Go users.

Why it matters: frontier labs are now competing on price per task as much as benchmark scores, and developers get cheaper models from both sides.