Anthropic Blocks xAI From Accessing Claude Models Over Competitive Use Violation

Summary

Anthropic restricted Elon Musk's xAI from accessing Claude models after discovering that xAI developers had been using Claude through the Cursor coding tool to accelerate internal AI development, violating Anthropic's commercial terms of service. xAI co-founder Tony Wu notified staff that "Anthropic models are not responding on Cursor." Section D.4 (Use Restrictions) of Anthropic's commercial terms expressly prohibits using its services to build competing products or train competing AI models.