Anytime players wish to take a non-magical action that has some consequence for failure, they're performing a skill check. The difficulty (sometimes called DC or target) should always be set (openly) by the Storyteller before players roll. If there's no penalty for failure, players shouldn't need to make a roll. It just slows down the important parts of the game.
Skill Checks are super simple : The Storyteller rolls 1d6. The player rolls 1d6. If the player's number is equal or higher, they succeed. If the player's number is lower or a 1, they fail.
For every condition, tag, or word against the player : The Storyteller rolls an additional 1d6.
For every condition, tag, or word in favor of the player : They roll an additional 1d6.
Words may be played individually, as they're being used in a non-magical capacity. Words used for skillchecks are still consumed as normal.
If a tag or word is exactly what the player is doing ("Steal" and you're stealing), any one of their dice gets +1 to its result.
Before difficulty dice are rolled :
The Storyteller should tell the player how many dice will be rolled for difficulty.
The player declares any tags that would reasonably apply for or against them. The Storyteller will affirm or negate each.
The player declares any words they will play to increase their dice.
Players may cancel anytime before the challenge dice are actually rolled.
Each die needs to be defeated individually, the numbers are not totalled. If a task is especially difficult (very rare), the number of challenge dice may be higher. Examples : breaking down a door, decoding the mcguffin, or dodging lightning.
The system is based around the concept of partial success. Wherever possible, the narrative should proceed in a way that describes the full outcome of the dice.
Example : The player wants to lie to someone that already hates them. The difficulty becomes 2d6 (+1d6 for unfavorable condition). The player plays the word [Convince] and their attempt becomes 2d6. Only one of the player's dice succeed. The person they lied to goes around saying "Well this is what the player said. I can't prove it but I don't trust 'im". The player has partially succeeded in that they are not being directly refuted on any specific ground. They suffer partial consequence in that the person doesn't 100% believe what they were told. They're half-convinced.
Example : The player wants to try to spot a hidden Orc. The Orc is wearing a ghillie suit that provides the word [Hide] and has used it while hiding. The difficulty to spot him is increased to 3d6+1. 1d6 base, 1d6 unfavorable condition (wearing camo), 1d6 opposing word ([Hide]) and +1 to one of those dice because he used [Hide] and is literally hiding. We'll assume the Orc rolled 1(+1), 3, and 4. Without a bonus, the best the player can hope for is to beat one of those dice. Assuming their 1d6 does overcome one of the challenge dice (at least a 2), they should get some level of success but not all. Perhaps they "see evidence someone was here" or "sense they're being watched".
Skill checks should only be used when there's a real penalty for failure or some force opposes the attempt. Our adventurers are assumed to be competent in their fields. Rangers can track things (that aren't actively hiding their tracks), bards can play songs (that they know), and everyone can move barrels across the room. The goal is to keep the narrative progressing and use these rules to resolve conflicts.
Storytellers may make secret rolls for passive checks. They should apply any relevant tags in favor of the player. Words should not be considered, as there's no opportunity to intentionally weave fates in their favor.