OpenAI improves GPT-5.6 Sol in ChatGPT and restricts free users to its weakest model
OpenAI tiers ChatGPT again: Sol gets smarter, Luna becomes the free ceiling.
Why it matters
OpenAI is reshaping ChatGPT's free tier around a weaker model (Luna) while advancing its flagship (Sol) with reasoning control. Practitioners need to recalibrate which tier suits their workflows; enthusiasts see the company doubling down on monetization via model quality gating.
The key facts
10 to knowGPT-5.6 Sol updated with 'more focused responses' and a reasoning slider for adjustable depth
Free users will access GPT-5.6 Luna (smaller model) with unlimited text chats starting next week
Luna users get a button to enable longer reasoning, but Luna still 'falls well short' of larger siblings
Tiering strategy: Sol (paid flagship) vs. Luna (free entry point)
Published Aug 6, 2026 on The Decoder
GPT-5.6 Sol updated with more focused responses and reasoning slider
Free users get unlimited text chats with GPT-5.6 Luna starting next week
Luna includes button for longer reasoning but remains weaker than larger siblings
Pricing/access story: free tier restricted to smaller model variant
Reasoning depth is now a user-adjustable parameter, not baked into the model
Go to the source
The Decoderthe-decoder.com
Publisher excerpt: OpenAI has updated GPT-5.6 Sol with more focused responses and a reasoning slider that lets users adjust how deeply the model thinks. Free users will get unlimited text chats with the smaller GPT-5.6 Luna starting next week, plus a button that lets Luna reason longer. But the smaller model still…