House Rule; A version of the Declarations rules for FATE are available as part of the Cypher system.
This is an expansion of the existing rules for spending XP to gain short/medium term benefits. Rather than gaining a skill or ability you declare a certain thing about the area, environment, or world to be true. This should have something to do with the nature of the character. For example, a character with the History skill might state that the decor of a palace dates is more than a hundred years old and that suggests a particular place where weapons would be displayed, and thus creates a place the characters can find arms in the heat of the moment, while a character who Employs Magnetism might determine that the table hidden under a tablecloth is made of a ferrous metal. Obviously, declarations cannot be made that relate to things already known to be false, such as trying to place such a weapons display in a location where the characters previously looked for them without success. While, generally, this will cost the player 2 experience points as a short/medium term benefit some declarations with more lasting significance may instead be 3 point long term benefits. Only rarely will a declaration will be instant, such as a fighter declaring that an opponent in the middle of an open ballroom has stepped directly below a chandelier.GMs have the right to veto any suggestions that seem out of scope (or ask the player to revise them), especially if the rest of the group isn’t buying into it, or they can veto with an offer for the character to make an appropriate skill check to get alternate similarly useful information instead. Finally, the GM can simply veto by giving the player an experience point, as a player refusing a GM intrusion.
The player can declare their character "notices" or "remembers" some piece of knowledge. Based on the obscurity of that knowledge the GM sets a DC and the player makes an Intelligence roll. Depending on the nature of the declared item, they may add their proficiency and other bonuses based on skills. For example, recognizing the god to which a now-defiled altar was once sanctified would be an Intelligence (Religion) roll or a warrior may use Intelligence(History) to know the background, and a particular weakness, of a fighting style an opponent uses.
If the DM has already determined a piece of information a player wants to declare, they treat the roll normally but provide the predetermined answer on a successful roll. Similarly, if a player attempts to determine information that the DM has not pre-decided after a successful roll the player may determine the answer as if they had made a declaration at the outset. As always, DMs have the right to veto any suggestions that seem out of scope, specifically asking the player to revise them, especially if the rest of the group isn’t buying into it.
Such pieces of information can be used to provide advantage or force disadvantage on a roll taken that they might influence. Only the character who made the discovery can use benefit unless they specifically share the information with another. After being used once it cannot be used again by any character with the party until after the character which used it takes a short rest.
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