Claude is Anthropic’s model family, served at claude.ai and, for software work, through Claude Code. It enters the corpus in the spiky-frontier comparison as the leader on creative writing, but its recurring role is as the model that builds models: Karpathy handed it his nanochat optimization loop, Anthropic’s chief product officer said it writes effectively 100% of the company’s product code, and by March it wrote 70–90% of the code behind future Anthropic models, the basis of the claim that recursive self-improvement is already happening.
AISystem
Claude
Anthropic's frontier model family, which the corpus follows from a creative-writing lead to writing effectively all of Anthropic's own product code.
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- Welcome to December 12, 2025 (theinnermostloop.substack.com)
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