Ninth Circuit Rules AI Agent Is a User Tool, Vacates Preliminary Injunction Against Perplexity

On August 4, 2026, a panel of the U.S. Court of Appeals for the Ninth Circuit issued a definitive ruling vacating the district court’s preliminary injunction against Perplexity AI and remanding the case for further proceedings. The core holding: it was the users of Perplexity’s Comet browser—not Perplexity itself—who accessed Amazon’s platform.

The case originated in November 2025, when Amazon sued Perplexity, alleging that the AI agent “Assistant” built into Comet browser had accessed Amazon’s password‑protected account systems without authorization, retrieved users’ private account data, and placed orders on their behalf—violating the federal Computer Fraud and Abuse Act (CFAA) and California’s Comprehensive Computer Data Access and Fraud Act (CDAFA).

On March 9, 2026, the U.S. District Court for the Northern District of California granted Amazon’s preliminary injunction in full, finding that Amazon had shown a substantial likelihood of success on the merits regarding the threshold issue of “access,” and that Perplexity had accessed password‑protected accounts through Comet with user permission but without Amazon’s authorization. Just one week later, however, the Ninth Circuit stayed the injunction. The appeal proceeded, culminating in the August 4 final ruling.

In its decision, the Ninth Circuit closely examined Comet’s technical architecture and determined that Assistant runs locally in the user’s browser, captures screenshots, sends them to Perplexity’s servers, receives operational instructions, and executes those instructions on the user’s machine. Critically, the court emphasized that Perplexity’s servers never directly accessed Amazon’s servers—a factual finding that proved decisive.

On the legal analysis, the panel invoked the U.S. Supreme Court’s definition of “access” in Van Buren v. United States (2021)—i.e., “to enter the computer system itself or a particular portion of it”—and made two key characterizations. First, it distinguished Facebook v. Power Ventures (2016), where Power’s servers actually sent messages to Facebook’s servers; here Perplexity’s servers did not directly interact with Amazon’s. Second, the court explicitly held that regardless of Assistant’s sophistication, it is a tool, not a legal person.

To illustrate, the panel used a “Safari analogy”: when a user visits Amazon.com in Safari and checks out, Safari automatically fills in stored address and payment information—yet no one would say Apple (Safari’s developer) accessed Amazon’s servers; common sense says the user did, and Safari was merely a tool. Similarly, Assistant’s screenshot‑and‑execute process is substantively the same—the tool carries out the user’s pre‑determined instructions, without independent intent.

The court further noted that because the CFAA is primarily a criminal statute, ambiguities must be construed in favor of the defendant. Adopting Amazon’s expansive reading could theoretically expose ordinary users who use AI agents for shopping to criminal conspiracy or aiding‑and‑abetting liability—a result Congress did not intend.

Importantly, the Ninth Circuit deliberately confined its holding to a narrow scope, to avoid being read as a general rule that “AI agents accessing websites are exempt from CFAA.” The court stated that its ruling does not establish a new legal framework for agentic AI, nor does it address whether Perplexity could be liable under other theories or in other contexts. The decision is limited to the concept of “access” under the CFAA and applies only to the specific interactions between Assistant and Amazon.com as documented in the record of this case.

Following the ruling, an Amazon spokesperson said the company respects but disagrees with the outcome, remains confident in its claims, and is evaluating next steps. The case is not yet concluded; the Ninth Circuit has remanded the case to the district court for further proceedings. China Intellectual Property Lawyer Network will continue to monitor developments.