Designing Traps for World of Darkness

World of Darkness doesn't have much in the way of traps for you to steal and make use of in your games so you'll need to create your own.  This is a bit unfortunate as there's even a whole Traps merit in the Hunter: the Vigil series of books but what can you do?  It is what it is.  Luckily you can generally live with just a few different different mechanics so long as you change the aesthetics.  This is one of the benfits of the World of Darkness' more limited skill set.
 

Mundane Traps

Trigger

Tripwire, pressure plate, concealed hole.

Generally the trigger for a mundane trap can be seen with a simple Wits + Composure check with modifiers equal to successes on the trap maker's Stealth check to hide it after she has Crafted it.

Effect

Swinging scythe, spikes (erupting), spikes (landing), poisoned edge, explosion,

tripping, poisonous gas, slamming, entangling and hauling up.

Any mundane trap seen in a videogame, movie or book and can be recreated here.  You could use alchemy and advanced processes to create a mine or explosive gases to justify an explosion when a door is opened.  Any number of sharp objects could be hurled or thrust at the characters.  Hidden needles loaded with poison could lurk on key holes.  Logs could be positioned to slam into characters and looped rope could tighten when tread on and tug them into the air.  You just need to figure out the attacking dice pool as well as it deals bashing, lethal or (argh!) aggravated damage.  Traps can also poison a person, forcing Stamina checks, or grapple them.

Disarming the Trap

Tripwire

Oftentimes the best method of disarming a trap is to avoid it.  Some can be disarmed by placing an equally heavy object on the pressure plate when removing another one (using larceny), playing around with the mechanism (using crafts), or simply cutting the rope and moving to one side so that the trap is used and exhausted.  With traps like pitfalls so long as you don't step on the thin layer of plant matter that obscures it then you should be fine.  Really good jumps, gliding, or simply using planks of wood should suffice if the pit stretches from wall to wall.

Magical Traps

Trigger

Tripwire, pressure plate, concealed hole.

Generally the trigger for a mundane trap can be seen with a simple Wits + Composure check with modifiers equal to successes on the trap maker's Stealth check to hide it after she has Crafted it.

Effect

Once the trap has sprung, what will happen?

There are plenty of effects for a magical trap that you can choose from which includes any offensive or enchanting spell or power.  One can imagine a Forgetful Mind effect that clouds the memories of anyone who lifts a chest lid and gazes inside - causing them to immediately forget what they saw once they drop the lid.  Or an Entrance spell that causes a person to love and adore a mundane trap - mistaking an about to swing scythe for something worth holding.  Then there's the various damaging Mage Rotes involving Forces or Death, certain psychic abilities just as Pyrokinesis, or Changeling Contracts such as the Touch of Paralysing Shudders from the Contracts of Darkness.  The trap will have its own dice pool.  As PCs can't create magical traps without completing a quest of your design to gather up the components, you might as well create the trap's dice pool.

Diagnosing the Effect

Strangely warm, ambient lighting in the room, odd glow, strange plant growths,

bizarre insectile behaviours, mysterious etchings, odd shadow play,

cold draught, static charge in the air, oddly echoing chamber.

Magical traps should have mystical and occult signifiers that can be determined through a mixture of the Occult skill and the Crafts (indoors) or Survival (outdoors) skill.  The same character must make a success on both skill rolls as they must not only notice what is weird but be able to tell that it is weird.  A cold draught might be the sign of something more or could simply be cause by a crack in the wall.  Only rogues with the right merit or those with certain relics can diagnose or identify a magical trap.  The Storyteller is free to make exceptions to this rule for certain traps when a character possesses a particular merit or has been exposed to this sort of trap before.

Disarming the Trap

The hard part....

Some magical traps only act once for a certain period time before falling inert so it can be easier to simply get someone else to trigger it.  If this isn't an option or the characters just aren't that cruel then a rogue with the right merit can clash their will against the trap (Resolve + Composure versus the trap's dice).  If you don't have a rogue, then someone with at least one psychic or ritual merit can attempt a clash of wills but they take a -3 penalty.  Alternatively some magical traps can be destroyed but doing so often unleashes an explosion of magical energy (damage is generally a number of dice equal to the trap's activation dice and deals bashing damage).