Notes on the xAI/Anthropic data center deal
Simon Willison · Simon Willison · 2026-05-07
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Topics: compute-infrastructureanthropicxai-spacexai-energy-usagesupply-chain-risk
Claims
- Anthropic is leasing all of Colossus 1's capacity from SpaceX/xAI while xAI retains the larger Colossus 2 for its own model training.
- Colossus 1 has a documented poor environmental record, having operated gas turbines without Clean Air Act permits or pollution controls by classifying them as 'temporary.'
- Elon Musk's stated right to reclaim compute if Anthropic's AI 'harms humanity' — with Musk as sole arbiter — creates a novel and potentially serious supply chain dependency risk for Anthropic.
- xAI gave only two weeks' notice before deprecating Grok 4.1 Fast and other models, frustrating developers who had recently migrated to that ecosystem.
Key quotes
I get that Anthropic are severely compute-constrained, but in a world where the very existence of 'AI data centers' is a red-hot political issue, signing up with this particular data center is a really bad look.
Presumably the criteria for 'harm humanity' are decided by Elon himself. Sounds like a new form of supply chain risk for Anthropic to me!