The news: The Ninth Circuit Court of Appeals vacated a preliminary injunction that had barred Perplexity's Comet agentic AI browser from shopping on Amazon on users’ behalf. The panel found Amazon was unlikely to succeed on its Computer Fraud and Abuse Act claim, ruling that when a user directs Perplexity’s AI assistant to complete a task on Amazon.com, it's the user—not Perplexity—accessing Amazon’s computers with the assistant’s help. The court reached the same conclusion on Amazon’s parallel California state law claim and remanded the case for further proceedings.

Zooming out: Amazon sued Perplexity in November 2025, alleging Comet violated its terms of service, degraded the shopping experience, and created privacy vulnerabilities. The retailer argued that AI-generated traffic forces it to filter fraudulent impressions before charging advertisers.

A district court granted Amazon a temporary injunction in March 2026 blocking Comet while the case proceeded, and Perplexity appealed, arguing Amazon suffered no real harm from the agent's activity. The Ninth Circuit agreed, ruling that the harms Amazon cited, the balance of the equities, and the public interest all favored Perplexity rather than an injunction.

Why it matters: Amazon is fighting to keep agents off its site because it wants to control the shopping experience, including the ads shoppers see. That’s a massive business: Amazon generated $19.8 billion in ad revenues in Q2 alone, and we expect it to generate $83.34 billion in ad revenues this year.

Implications for retailers and advertisers: The ruling is a clear setback for Amazon and its effort to wall off its site from agents. But Amazon’s position may not mirror smaller ecommerce players that may still welcome the traffic if it converts into sales—even if that also invites a race to the bottom on price. Amazon’s dominant share of the marketplace and retail media landscape gives it both more to lose and more resources to keep fighting.

That said, the case is far from over. Amazon can seek rehearing or ask the US Supreme Court to take it up, and the underlying lawsuit continues in federal court in San Francisco. That keeps open the broader question of whether platforms can use terms of service to block AI agents.

For now, retailers and advertisers should brace for more shopping agents. And even though the number of consumers using agents to shop remains small, brands should optimize product data, reviews, and metadata so agentic tools can find, rank, and recommend them.

Go further: Read our report, The State of AI Shopping Assistants.