Most AI-agent browser demos stop at the easy part: open a page, search for something, click a link, extract a result.

That proves the model can drive a browser. It does not prove the workflow is production-ready.

The failures usually show up one step later, when the agent has to operate like a real user inside a real account.

Failure 1: login is treated as a one-time setup

A lot of agent workflows assume login is already solved. In practice, it is where the real product work starts.