Appeals Court Agrees with EFF that Building a Web Browser Doesn’t Violate the CFAA

The Ninth Circuit Court of Appeals has endorsed a commonsense technical interpretation of the Computer Fraud and Abuse Act (CFAA), a law not usually given to such interpretation. Amazon had sued Perplexity AI to try to shut down its Comet browser, claiming the browser’s optional agentic AI “Assistant” that can browse websites like Amazon for comparison shopping purposes, violated the CFAA because Amazon did not “authorize” Perplexity to access Amazon users’ accounts. Rejecting that theory, the Ninth Circuit held that Perplexity was unlikely to be liable because users operate the tool, not Perplexity.

That’s the right conclusion, as both a legal and technical matter. As we explained to the court in our amicus brief, the CFAA requires unauthorized “access,” and Perplexity itself does not access Amazon’s servers—users of the Comet browser do. The court agreed, noting that EFF’s explanation “articulates the nature of the system most clearly.”

The court noted that agentic AI may present novel legal issues, and there is “little to no existing caselaw directly dealing with how to ascribe responsibility for AI agents like the Assistant, let alone caselaw specifically dealing with agentic AI in the CFAA context.” Ultimately, though, thorny questions of AI “intent” were irrelevant to this case, because the Assistant “is a tool, not a person for statutory purposes.” And, the court concluded, it is a tool operated by users, not Perplexity. Even…