Take over a creature, speak as it, and give it back exactly as it was - from a vanilla client or a modded one. Plus the lock that frees your aim, the buttons, the keys, and dressing a cast.
Possession
/st possess picks the best form your client can manage, without asking you which
client you are on - it asks the connection whether it negotiated StoryTeller's channel. Say it again
to let go.
You are the creature: your own controls, your own mouse, your own jump. It goes where you
go, hidden from your first-person view, and the room sees only it. Works on Cast NPCs too, human
bodies included. /st possess drive
You keep your own body and view, and the creature walks to wherever you walk - led rather than
driven, bound by its own legs, so a possessed cow will not scale a cliff the audience can see it
could not climb. /st possess steer
The camera binds to the creature and you see what it sees while it carries on being itself. You
can speak as it, but not steer or look around - sneak to step back out. That limit is vanilla's:
a client sends no movement while spectating an entity. /st possess eyes
Nothing is destroyed. A possessed creature keeps every goal it was born with; possession adds one on top that holds its movement, and releasing removes exactly that one. A Storyteller who logs out mid-possession lets the creature go, and a creature that dies hands the camera back rather than leaving you watching through a corpse.
It is not spectator mode. A spectator flies and passes through
walls, so the body it leads gets walked into the air or into the ground. Possession leaves you
grounded; /st drift keeps spectator for what it is good at, the godlike survey of
a scene.
You are hidden while you wear a body, if SableCraft Standards 1.6.0 or newer is installed, and given back to the world when you let go - unless you had vanished yourself first, in which case you stay hidden and are told why. Without it, possession still works; it just cannot hide you. A slime or magma cube cannot be led, since they move by jumping, and the mod says so - eyes and voice still work on them.
Targeting and voice
Every creature command aims at what is in your sights - no names, no ids, no selectors. That is the right default, but it wants your head still: a costume is several commands, two mobs a block apart trade places under the crosshair, and walking a possessed cow across a room means looking where it should go, which is not at it.
/st lock makes the creature in your sights the target until you say it
again, or /st unlock. Possess, say, dress, behave and save all mean that one
afterwards. It never fails quietly: if the creature dies,
unloads or leaves the world, the lock ends and says so, rather than pointing your next command at
whatever the crosshair happens to find.
/st say <words> speaks as the creature to anyone close enough to hear - possessed
or merely locked, so a shopkeeper can hold a whole conversation while keeping its own behaviour. It
does not fall back to the crosshair: words put in the mouth of a creature nobody chose cannot be unread
by the table.
Buttons
With SableCraft Standards installed, the most-used tools - possess, lock, drift, next and summon - appear on its action bar: drawn for anyone running the Standards client, and as a row of clickable chat buttons for anyone who is not.
A button sends /st possess exactly as if it had been typed, so buttons cannot
drift ahead of the commands, and permissions behave identically either way. Five buttons rather
than nine, because the commands toggle: there is no separate Release or Return.
They report state, not just availability. Possess lights up and names what you are wearing; lock names what it holds. A Storyteller who can see "you are wearing a cow" notices a possession that has quietly ended, instead of finding out three commands later.
Keys
With StoryTeller on the Storyteller's own client, five keybinds appear under
Options > Controls > StoryTeller: possess, lock, drift, next and summon. A
command wants your hands off the mouse and a button wants a screen open; neither works while you are
still tracking a creature across the room. A key does.
They arrive unbound. Exactly one player on a server is the Storyteller, and a mod that claims letters on install is how conflicts start - you are told once, on joining, that the keys exist. Each sends the same command a button would, and on a server that does not offer the command, a key does nothing at all.
Dressing the cast
With SableCraft Cast installed, /st cast equip <slot> <item> dresses the NPC in
your sights - or the one you have locked, which is what makes dressing bearable. Slots are
mainhand offhand head chest legs feet, and the item is written exactly as
/give takes it, components and all, so a named sword or a tipped arrow works.
Leave the item off to strip the slot.
/st cast worn lists what an NPC has on, in a fixed slot order. Cast NPCs only: a
wild creature's gear is its own, and this mod could neither undo nor remember putting a helmet on a
passing zombie.