It would be great to have a space for narrator "house rules" or conventions. You can have a boilerplate on how you do things and send it to people in your game when you start. You could also have multiple contracts, where you have different ones for different games or style of games. Another way to think of the contract is sort of like a "style guide" for the game.

"I want to make this story very hardboiled and low magic", etc.