A couple of years back, Chris Chinn created the The Same Page Tool . I recently discovered this and am quite excited about it – it seems like a really concise way to agree how you will play an rpg game or campaign.
In essence, it’s a form that you complete as a group, agreeing things like GM authority, expectation of linear story versus sandbox or some other structure, whether PCs should always work together. Crucially, it’s not intended as a survey: you fill in one form, with one tick per category, for one group playing one run or campaign.
I’ve taken Chris’s original version, combined it with some stuff from the Milton Keynes RPG club version, and put it up here.