I am a Dungeon Master.
As a D&D Dungeon Master, I have certain expectations. I consider these to be reasonable and applicable to everyone who sits at my table.
As the DM, I have control over my world. I am the final authority on everything that happens in the world. I decide what rules we use; I populate the world with places, characters and creatures; I set the tone and genre for the game. When my players ask a question about the world, I will know the answer. If I do not know the answer, I will find it or make an answer, as appropriate.
As the DM, I do not control the players’ characters. They are free agents in my world. I will not tell them what their characters do, only what their characters can experience about the world around them. This does not relieve the players of any sort of responsibility; the world will react to their presence and their actions in a manner that logical and consistent, given the circumstances.
I will know the rules.
I will apply the rules consistently and fairly. I will not roll the dice (or call for a roll from the players) without a full understanding of the implications of that roll. I will accept the results of any roll as-is. I will not cheat or roll my dice behind a screen, but out in the open where the players may see them. If asked, I will tell the players why I (or they) are rolling, insofar as their characters are able to perceive the answer.
In the absence of clear rules for a given situation, I will make a ruling and keep the game moving forward. I will revisit that ruling in-between sessions with the intent to write a clear and concise rule that can be used in future sessions.
When writing new rules, I will consider the following factors: existing rules; real-world comparisons; practical implications (game theory); and the willingness of my players to apply or follow the rule. I will be responsive to feedback from my players concerning new rules.
I will get to know my players. The game’s action is driven by their choices. They set the agenda; they determine their own goals. While the world is independent of the players’ characters, I will nonetheless present them with opportunities that align with their goals (and make sense given their place in the world).
I will learn about the real world. I will apply as much of my knowledge about the real world to the game world. In this way, I will use real-world information to create a better understanding of our shared fantasy world.
I will study game theory. I will learn how people play games and how they react to various choices. I will apply this knowledge to create good rules for my game, that suit my players’ behaviors and tastes in the game.
I am the players’ eyes and ears. They cannot know anything about the world except what I tell them. If the players ask a question, I will give them an answer, insofar as they are able to conceivably know it. When in doubt, I will err on the side of caution and give the players more information.
I will provide my players with opportunities to adventure in my world. I will not hold their hands. I will not force them to follow a path. I will offer choices and I will present the world in a manner that encourages behavior, but does not force it.
I will tell the players what their characters know and think and feel, but only insofar as the moment is happening or as the rules apply to their character. I will not force a player to play a character according to a fleeting emotion. I will not insist the players avoid bringing information to the table from outside their character’s limits.
I seek to create tension and drama in the game. I want my players to succeed but it is my job to put obstacles and challenges in front of them. If I do not do my job well, they will have a less-than-satisfactory experience at my table. To accomplish this goal, I will not pull punches; I will not hide my dice rolls; I will not cheat or fudge or change stats in the middle of a game. I will give the players as much information as they need (and sometimes more) so that they can make good decisions about the course of their game.
I will moderate the social interaction at my table. The players are members of a team and this is a team game; their success or failure depends on their ability to work together. If they struggle with this, I will step in to provide guidance and advice. If a particular player is behaving poorly, is out-of-line, displays toxic attitudes or is generally being a bad person, I will address that player in the moment. I will not seek to embarrass or make any player uncomfortable as a person. Tension in regard to the characters is one of my goals for the game. Tension in regard to the players is not.
As a DM, I expect that my players hold similar views and play in a manner consistent with these expectations.