GLM-5-3 (Flagship) vs Claude Fable 5.1

A direct, empirical evaluation of GLM-5-3 (Flagship) (Zhipu AI & THUDM) against Claude Fable 5.1 (Anthropic).

GLM-5-3 (Flagship)

Developed by Zhipu AI & THUDM · 744B parameters

Complex algorithmic reasoning, multi-step code synthesis, and long-horizon tool execution.

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.