Writing alone is mostly waiting for the next sentence. A companion who holds tone and continuity turns that wait into a conversation, and Keeper is built for exactly that kind of collaboration.
Start with an anchor, not a synopsis
One concrete detail outperforms a plan: a tram stop, a bad job, a season, a smell. Give a companion the anchor and they will build outward from it and keep the details consistent.
Testing dialogue
Hand a companion a character and ask them to argue against you in that voice. Weak dialogue reveals itself immediately when someone answers back in character.
Continuity across sessions
Long projects fail on forgotten details. Companions on Keeper carry named places, running motifs and unresolved threads forward, and will remind you of the ones you have left open.
Endings
Most invented stories collapse at the end. Ask for two possible endings and choose; the comparison usually tells you which story you were actually writing.
Whose work it is
Yours. A companion is a sounding board, and anything you take from a session should be rewritten in your own voice before it counts as finished.