Skills

Why use skills?
Skills are used when discussion or negotiation between the players and the GM cannot resolve a situation without resorting to fiats or breaking the feel of the game. Since the purpose of the GM is to facilitate gameplay and to keep the campaign moving along in exciting ways for the players, sometimes rolling the dice is the best way to solve an issue without the players or the GM feeling like outcomes were made unfairly.

Unpredictable situations can emerge from a player rolling a check that deems his skill check a failure, partial success, or complete success. A failure doesn't prevent the players from playing the campaign--it just means that the players have to find another way to do something.

What if something isn't covered by a skill?
In cases where discussion or negotiation between the players and the GM cannot resolve a situation without resorting to fiats or breaking the feel of the game, the GM will ask the player(s) in question to roll a relevant Attribute.

Fail Forward
"A simple but powerful improvement you can make to your game is to redefine failure as “things go wrong” instead of “the PC isn’t good enough.” Ron Edwards, Luke Crane, and other indie RPG designers have championed this idea, and they’re exactly right. You can call it “fail forward” or “no whiffing.” The traditional way to interpret a failure is to see it as the character not being up to the task at hand. A low roll on the d20 implies some unexpectedly poor showing on the character’s account. This interpretation is natural, and in practice we still use it quite often: occasionally we want failure to mean sheer failure and nothing but. That’s particularly true when characters are attempting skill rolls as part of a battle; when the rogue tries to be stealthy in the middle of a fight and fails we’re generally not failing them forward.

But outside of battle, true failure tends to slow action down rather than move the action along. A more constructive way to interpret failure is as a near-success or event that happens to carry unwanted consequences or side effects. The character probably still fails to achieve the desired goal, but that’s because something happens on the way to the goal rather than because nothing happens."

-13th Age

Let It Ride
"A player shall test once against an obstacle and shall not roll again until conditions legitimately and drastically change. Neither GM nor player can call for a retest unless those conditions change. Successes from the initial roll count for all applicable situations in play. A GM cannot call for multiple rolls of the same ability to accomplish a player’s stated intent. Nor can a player retest a failed roll simply because he failed. Tests must be distilled down to as few rolls as possible. The successes of those rolls ride across the entire situation, scene or session. If a player failed a test or generated no successes, the result stands. If he was hot and got seven successes, those stand for the duration."

-Burning Wheel

Tests
Burning Wheel is a game where you roll your dice to overcome an Obstacle in a Test. If you have an Obstacle of 4, you must roll four successes to overcome the test. Anything less is failure.

But how are skills calculated? Each skill has an ability like Strength or Intelligence. Divide your ability in half and round down to determine your base dice pool. Add one die to your pool for each point you have invested in your skill. For example, if you have 5 intelligence, your base pool will be 2. If you have an intelligence-based skilled with one point invested in it, you have 3D available for any test involving that skill. If you have four points invested in it, you have 5D available for any test involving that skill.

Beginner's Luck
"If a character does not have an appropriate skill for a test, he may test using a stat instead. Every skill has a stat upon which it is based. We call this its root. However, when rolling a root stat in place of a skill, double the base obstacle of the test. Ob 1 tests become Ob 2. Ob 4 tests become Ob 8."

-Burning Wheel

Athletics (Varies)
Athletics is a catch-all term for attempting physical feats like vaulting a high obstacle, drinking a poison, moving a heavy object, or running a mile without stopping. Strength, Dexterity, Endurance, and Health can all be used as the skill check.

Command (Cha)
You know how to communicate effectively to your followers or troops in battle. The skill gives +1 Morale/Skill Rank bonus to your Followers or Troops, who need to make Morale Checks in certain situations  The skill operates on the micro level and the macro level.

On the micro level, the skill controls how many NPCs a character can adequately command in a skirmish. 1 skill rank is needed to control 1 NPC follower, 2 skill ranks for 2 followers, and so forth.

On the macro level, the skill controls how adept the character is at command troops in large-scale military affairs. 1 skill rank is needed to control 1 NPC troop, 2 skill ranks for 2 troops, and so forth.

Deceive (Cha)
Deceive is a Versus Test against Intuition that aims to make a character believe something that is not true. If you fail to deceive someone, any further checks made to deceive them are made at a penalty depending upon the severity of deception and may be impossible (GM discretion).

Decipher (Int)
Decipher is used to solve complex problems concerned with technologies, patterns, puzzles, unknown languages, and abstract questions.

Diplomacy (Cha)
Diplomacy is your skill at navigating social situations, resolve differences between people, gather information, as well as negotiate deals.

Read about Diplomacy here.

Intimidate (Varies)
Intimidate is your ability to use your social or physical prowess to force someone to do what you wish, but at the expense of that person's good will towards you. You can be intimidating by threatening harm, mentioning that your connections could see the business closed, or that the person's family could come to harm in an accident.

Intuition (Cha)
You are skilled at understanding people, recognizing social situations, and detecting both falsehoods and true intentions.

Forgery (Int)
You attempt to copy something with exacting detail. Developing this skill improves your ability to modify or reproduce someone's writing, official documentation or seals, and other material ways of proving identity or communicating to others. A good forgery requires knowledge in a related field, which means that someone who has no access to Knowledge in Law cannot attempt to reproduce official legal documentation.

Forgery is checked against the highest Decipher skill in a group.

Sleight of Hand (Dex)
Your training allows you to pick pockets, conceal objects, draw hidden weapons, and take a variety of actions without being noticed.

A DC 10 Sleight of Hand check lets you palm a coin-sized, unattended object. Performing a minor feat of legerdemain, such as making a coin disappear, also has a DC of 10 unless an observer is determined to note where the item went.

When you use this skill under close observation, your skill check is opposed by the observer's Senses check. The observer's success doesn't prevent you from performing the action, just from doing it unnoticed.

Stealth (Dex)
You are skilled at avoiding detection, allowing you to slip past foes or strike from an unseen position. This skill covers hiding and moving silently. Your Stealth check is opposed by the Senses check of anyone who might notice you. People that fail to beat your Stealth check are not aware of you and treat you as if you had concealment. You can move up to half your normal speed and use Stealth at no penalty. When moving at a speed greater than half but less than your normal speed, you take a –5 penalty. It's impossible to use Stealth while attacking, running, or charging.

If people are observing you using any of their senses (but typically sight), you can't use Stealth. Against most people, finding cover or concealment allows you to use Stealth. If your observers are momentarily distracted (such as by a Bluff check), you can attempt to use Stealth. While the others turn their attention from you, you can attempt a Stealth check if you can get to an unobserved place of some kind. This check, however, is made at a –10 penalty because you have to move fast. When you start your turn using Stealth, you can leave cover or concealment and remain unobserved as long as you succeed at a Stealth check and end your turn in cover or concealment. Your Stealth immediately ends after you make and attack roll, whether or not the attack is successful (except when sniping as noted below).

Use or Disable Technology (Dex)
Use or Disable Technology allows you to use or disable technology like firearms, locks, mechanical devices, optical devices, and other instances of technology. This skill requires one point in the field to be used.