How Claude Duet signs in for you without seeing your password
A video breaks down Claude Duet's credential design: passwords are encrypted in an in-app form and typed by a cloud browser so the model never sees them, tokens are swapped by a proxy, and purchases use one-time cards approved in Link.
CLAUDE DUET NEVER SEES YOUR PASSWORD, AND HERE IS HOW IT STILL SIGNS IN FOR YOU An agent that works while you are away needs your logins. Anthropic's answer: it never gets them. The password path → you type it into a form inside the app → the form encrypts it with a single-use key → the cloud browser machine opens it and types it into the site → the model never sees it and cannot save it Sign-in tokens → the agent's machine only holds a placeholder → a proxy outside it swaps in the real value as the request is made Buying things → a one-time card, limited to that shop and that amount → you see the item and the total, and approve in your Link app → the real card number is not shared with Duet or the shop Approvals → a separate check runs outside the model → hidden page text can't steer it → for sending, paying, deleting: you see the action and every recipient Off-limits even with your approval → trading securities → moving money between accounts → anyone else's account The form encrypts, the browser types, and you approve. It is still a research preview, and Anthropic says the checks will sometimes miss something. Next time an agent asks for your login, ask where the password goes.