Editing Unwritten: System Reference Document/Game Basics (section)

===Compels===
Sometimes (in fact, probably often), you’ll find yourself in a situation where an aspect complicates your character’s life and creates unexpected drama. When that happens, the GM will suggest a potential complication that might arise. This is called a compel.

Sometimes, a compel means your character automatically fails at some goal, your character’s choices are restricted, or simply that unintended consequences cloud whatever your character does. You might negotiate back and forth on the details a little to arrive at what would be most appropriate in the moment. In our hunter example, if the character was challenged to a bet, the GM could compel Hotshot Big Game Hunter to decide that the bet ends up being more risky than the character expected, and the results stir up all sorts of trouble.

Once you’ve agreed to accept the complication, you get a fate point for your troubles. Alternatively, you can pay a fate point to prevent the complication from affecting your character, but we don’t recommend you do that very often—you’ll probably need that fate point later, and getting compelled brings drama (and hence, fun) into your game’s story.

Players, you may also call for a compel when you want there to be a complication in a decision you’ve just made, if it’s related to one of your aspects. GMs, you call for a compel when you make the world respond to the characters in a complicated or dramatic way.

Anyone at the table is free to suggest when a compel might be appropriate for any character (including their own). GMs, you have the final word on whether or not a compel is valid. Speak up if you see that a compel happened naturally as a result of play, but no fate points were awarded.