KKenechukwuindataintelligence.hashnode.dev·16h ago · 8 min readGPT-6 Astra vs Claude Fable 5.1Forty-eight hours. That's how long OpenAI waited after Anthropic shipped Claude Fable 5.1 and Claude Mythos 5.1 on September 1, 2026, before answering with GPT-6 Astra on September 3. Same list price:11B