Personalities and viewports
Vary who the simulated user is and what screen they use.
Personalities
A personality shapes how the agent behaves while it works through your steps: how patient it is, how carefully it reads, how it reacts when the interface surprises it. Running the same suite with different personalities is a cheap way to find issues a single idealised user never hits, such as an impatient user double-clicking a slow button.
Personalities are managed per project, and a test picks the personality it runs with.
Viewports
Each test also chooses a viewport, so the agent sees your site the way a desktop or mobile visitor would. A checkout flow that passes on desktop and fails on a phone-sized viewport is one of the most common real-world regressions; running the same journey at both sizes catches it before your users do.