The template I use on my games, FWIW:
Golden Rule
Don't be a jerk. Don't cheat, harass, flame, stalk, etc. or you will be shown the door.
Don't Break the Game
Respect the theme when it comes to plots, characters and setting. Do not do things that will destroy or irrevocably disrupt the theme for others. Use common sense, and when in doubt - contact the staff.
Player-Run Plots
Every player is encouraged and empowered to run plots, large and small. Just remember the Don't Break the Game rule above. Staff will run plots, of course, but proactive players will get the most out of the game.
Staff Pledge
We will do our best to provide a sane, fair and friendly environment for you to tell your stories. Our goal is to respond to all apps and requests in under 24 hours. Staff alts are all public, and we do not spy on players.
Other blurbs include Rating, Alts, Consent, and Idle. They're just a few sentences each, so it's pretty short. Personally I prefer to read them all in one place, but that's a matter of preference.
I think lightweight policies are best. You don't need a lawbook to run a game. People won't read it anyway. Just outline your general expectations, and beyond that, use "dinner party rules". It's my dinner party. I don't need to provide each guest with a comprehensive list of unacceptable behaviors. If you're being a jerk, I will talk to you about it. If you persist in being a jerk, I will ask you to leave.