Has OpenAI’s GPT-5.6 class beaten Anthropic’s Fable-class models?

Just over a week after Fable 5 came back online for all users, OpenAI unveiled its own next-generation family: GPT-5.6 Sol, Terra, and Luna. Rather than a single flagship, OpenAI split the release into three capability tiers priced separately with Sol at the top and Luna at the bottom, arguing this lets each tier advance on its own tempo.