Hacker News Reader

Note that every webpage does not have full JS execution privileges on other parts of the web.

At least in this case (not so sure about the Prompt API case mentioned in another thread) the agent is "in" the page. And that means that the agent is constrained by the same CORS limits that constrain the behavior of the page's own JS.

If you think about it, everything we've done to make malicious webpages unable to fiddle around with your state on other sites using XHRs, are exactly and already the proper set of constraints we'd want to prevent models working with webpages from doing the same thing.

CORS protects your Facebook from your Gmail, but it won't protect your Gmail from the agent itself since it already has access to the DOM and JS context. If that agent gets hit with a prompt injection and decides to "Delete all mail" or exfiltrates session tokens to a third-party endpoint, the browser sandbox will actually facilitate it because it views those as legitimate user-initiated actions

Reply on news.ycombinator.com