Actions are anything a player can imagine their Actor doing in an RPG. Action Cards group all possible actions into broad categories called Action Tags, or just Tags. Each Action Card lists a number of these ActionTags, and each Action Card is associated with one of the 9 Trine Attributes.
Action Tags are paired with the Attribute that is most important to successfully accomplishing an Action. For example, you would play the Strength Action Card when attacking an opponent with a heavy melee weapon, but would play the Agility Action Card if attacking with a fast light weapon. Similarly, the Knowledge Action Card would be played when trying to successfully research a topic in a library, or the Presence Action Card to successfully talk your way past the guards.
While playing the game, it is expected that a player will role play some statement that they intend their Actor to attempt while playing a Trine Aspect Card. This is called the Statement of Intent. The TA card limits the Action Card that may be played next to one of the 3 Attributes associated with that Aspect (see The Trine). After the Action Card is revealed during a Hand, a player is allowed a brief justification of why that Action made sense given their earlier Statement of Intent. This is known as the Bluff Space rule, and is intended to prevent what a player says while role playing from allowing opposing players to automatically guess what TA & Action cards they are about to play.
The Action Tags printed on the cards are not intended to be an all-inclusive list of all possible actions. Instead, they are broad categories of actions intended to give you the idea, and what kinds of other actions might also go with that Attribute, even if not explicitly printed on the card.
Choosing the right Action Card to play along with a stated action while role playing should feel intuitive once you have memorized what the 9 Attributes represent. If you aren't sure which Attribute governs success of an Action you intend your Actor to take, ask the GM (in a way that won't reveal your cards during a Hand).
Below are a list of Action Tags printed on the Action Cards from the Core Rules, as well as an extended list of other possible Tags for each Attribute. These are provided to help familiarize players with the types of Actions that go with each Attribute, so you can guess them intuitively during the game without asking the GM.
When making a physical attack during a Conflict, the Actor may bid any Attribute from the Body Aspect (STR, AGI, or FIT). For example, a Longsword may be designed to Slash(FIT), but can also be used to Pierce(AGI) with a thrust, or Crush(STR) as with a pommel strike. This variability is built into the Core Rules to allow Bluff Space.
The Weapons Extension introduces Primary Attributes and tradeoffs when bidding different Attributes if that level of detail is desired.
Mind and Spirit attacks work in the same way: the Action Tag is a guideline as to what Attribute must be bid, but the way a Player chooses to describe their Action while role playing is intentionally allowed to be able to be misleading so as to create Bluff Space at the table.
Player @ Conflict Step 2.3 (State Intent) – “As quickly as I can I try and convince him [opponent] of the error of his ways.” This signals other players that he will probably bid Mind or Spirit Aspect. Mind would encompass bidding Reason, using his Knowledge of the opponent's history to convince him, or Quickness to fast-talk him. But perhaps he is instead trying to dominate him (Willpower), or persuade him (Presence), or just guess what words he could say that might move his opponent (Intuition).
Player @ Conflict Step 2.5 (Aspect Reveal)– reveals the Spirit Aspect card
Player @ Conflict Step 3.3 (Attribute Reveal) – turns the Presence Attribute card face up.
Player @ Conflict Step 3.4 (Justification) – “I appeal to his sense of right and wrong to persuade him that there is a non-violent way to resolve this.”