A US judge has ruled that Anthropic must face key claims that it misled customers about how much use they get from its Claude Max plans. Magistrate Judge Alex Tse dismissed several other claims on Friday, Courthouse News reported.

The proposed class action, Kahn v. Anthropic, is in the federal court for northern California. TNW has not read the ruling.

Anthropic told buyers that its $100 and $200 Max plans give five or 20 times more usage than its Pro plan. However, the lawsuit, filed in June, says the plans give far less over a full week.

The plaintiffs, Karl Kahn and Solomon Smith, calculated that for one Claude model, the $200 plan gives six times Pro’s weekly usage. The $100 plan gives 3.5 times, they said.

The gap comes from how limits work. Max users get five or 20 times more use in each five-hour session, but their weekly limits are not five or 20 times higher.

Anthropic argued that customers should understand the extra usage as applying per session, and pointed to a help page. Tse was not persuaded, according to Courthouse News.

“Anthropic’s per session disclosure is located two hyperlinks away from the primary sales pages on claude.com,” Tse wrote.

Because customers pay monthly, they could reasonably read the promise as applying each month, the judge found. The plaintiffs can go ahead with claims of negligent misrepresentation and breach of contract.

Meanwhile, Tse dismissed claims under two California laws on unfair business practices and false advertising. He also dismissed Kahn’s claim under a state consumer law, but gave him the chance to add detail. Smith’s claim under that law survived.

Tse also rejected a claim that Anthropic acted unfairly by tightening usage limits during billing periods. Anthropic and the plaintiffs did not immediately respond to Courthouse News. Separately, Anthropic renamed the Max plans last week.