SAN FRANCISCO, June 26 -- When Anthropic filed its complaint with the Senate Commerce Committee last week, it came with a specific request: pass legislation making it illegal for Chinese AI companies to train models on the outputs of American ones. The target was Alibaba's Qwen series. The underlying legal theory, that systematically querying a competitor's commercial API at scale to generate training data constitutes intellectual property theft, has never been tested in a federal court.

Congress, moving faster than the courts, appears inclined to act on it anyway.

The allegation Anthropic brought to the committee is detailed. The company told senators that Alibaba had systematically run carefully crafted prompts through Claude's API at...