Sneak

You move up to half your Speed while trying to stay or become undetected (you can Sneak while burrowing, climbing, flying or swimming instead, at half that Speed). If you're undetected by a creature and it can't possibly see you (you're invisible, it's blinded, or you're in darkness it can't see in), any critical failure on your Sneak counts as a failure, and you stay undetected even without cover or concealment. At the end of your movement the GM rolls your Stealth check in secret against the Perception save of each creature you were hidden from or undetected by when you started. Cover or greater cover all the way gives +2 or +4 (Taking Cover doesn't add more while moving). You don't roll against a creature you're neither concealed from nor in cover from at the end; it observes you automatically.

Success: You stay undetected by the creature during and after your movement. You become observed as soon as you do anything but Hide, Sneak or Step; if you Strike, the creature is still Off-Guard against that attack and then observes you; anything else makes you observed just before you act unless the GM decides otherwise. Speaking or making a deliberate loud noise makes you hidden instead of undetected. If a creature Seeks and you become hidden to it, you must Sneak again to become undetected.

Failure: A telltale sign gives away your position, but you're still unseen: you're hidden from the creature during and after your movement.

Critical Failure: You're spotted: the creature observes you during and after your movement. If you're invisible and were hidden from it, you're hidden instead of observed.

Results

Success

You stay undetected by the creature during and after your movement. You become observed as soon as you do anything but Hide, Sneak or Step; if you Strike, the creature is still Off-Guard against that attack and then observes you; anything else makes you observed just before you act unless the GM decides otherwise. Speaking or making a deliberate loud noise makes you hidden instead of undetected. If a creature Seeks and you become hidden to it, you must Sneak again to become undetected.

Failure

A telltale sign gives away your position, but you're still unseen: you're hidden from the creature during and after your movement.

Critical Failure

You're spotted: the creature observes you during and after your movement. If you're invisible and were hidden from it, you're hidden instead of observed.