Claude Fable 5.1 vs GPT-6 Astra
A direct, empirical evaluation of Claude Fable 5.1 (Anthropic) against GPT-6 Astra (OpenAI).
Claude Fable 5.1
Developed by Anthropic · Proprietary Frontier parameters
Full-repository software refactoring, agentic tool workflows, formal verification, and 1.5M-token needle retrieval.
GPT-6 Astra
Developed by OpenAI · Proprietary Frontier parameters
Complex multi-step engineering, formal math proofs, autonomous computer/browser navigation, and CAD synthesis.