This is copied from unearthed arcana
Action Points
Action points give character the means to affect game play in significant ways, by improving important rolls or unlocking special abilities. Each character has a limited number of action points, and once an action point is spent, it is gone for good.
Metagame Analysis: Action Points
Action points give players some control over poor die rolls. Although this has little effect in an average encounter, it makes it a little more likely that characters will survive extremely challenging encounters and less likely that a single character will fall to what would otherwise be a balanced foe because of bad luck. A reserve of action points lets even careful players expose their characters to more risks, heightening the game’s tension and opening the door to even more heroic action. This variant also makes it less likely that an entire adventuring group will fall victim to one powerful effect, such as circle of death or cloudkill.
Action points also make it more likely that the use of a character’s most potent abilities will be successful. For example, although its overall effect on an encounter might be minimal, few things frustrate a paladin more than missing with a smite attack—an event that becomes less likely when using action points.
That said, action points can also lead characters to routinely get in over their heads (relying on action points to save themselves), and for GMs to unconsciously increase the difficulty of encounters (since characters are more likely to succeed against foes of equal power). This is as fine as long as the characters have a reserve of such points to spend—but if they run out, encounters that would otherwise be merely challenging can become incredibly deadly. Keep the number of action points available to your characters in mind when designing encounters.
For GMs who are worried that action points increase the power level of characters without an offsetting cost, there’s an easy solution. Just think of each action point as a one-use magic item with a broad range of possible effects. With that analogy, it becomes easy to justify reducing the amount of treasure awarded to balance out the accrual of action points. Note that this is merely a tool for GMs interested in carefully monitoring character power levels; action points should never be for sale.
An action point is roughly equivalent to a magic item worth 100 gp per character level (since the higher a character’s level, the more potent the effect).
Acquiring Action Points
A beginning (1st-level) character starts the game with 5 action points. A character above 1st level starts the game with a number of action points equal to 5 + 1/2 his current character level.
Every time a character advances, he gains a number of action points equal to 5 + 1/2 his new character level. Some prestige classes might allow a faster rate of accrual, at the GM’s option.
Action Points and Existing Games
Adding action points to an existing campaign is easy, since characters don’t need to make any special changes. Each character simply gains a number of action points equal to 5 + 1/2 his character level.
NPCs and Action Points
Most NPCs probably shouldn’t have action points, due to the added complexity this would create. In the case of important villains or other significant characters, however, the GM may award them an appropriate number of action points to use against the player characters. A number of action points equal to 1/2 the NPC’s level is a good baseline.
Using Action Points
You can spend 1 action point either to add to a single d20 roll, to take a special action, or to improve the use of a feat.
You can spend 1 action point in a round. If you spend a point to use a special action (see below), you can’t spend another one in the same round to improve a die roll, and vice versa.
Add to a Roll
When you spend 1 action point to improve a d20 roll, you add the result of a 1d6 to your d20 roll (including
attack rolls, saves, checks, or any other roll of a d20) to help you meet or exceed the target number. You can declare the use of 1 action point to alter a d20 roll after the roll is made, but only before the GM reveals the result of that roll. You can’t use an action point to alter the result of a d20 roll when you are
taking 10 or
taking 20. Depending on character level (see table), a character might be able to roll more than one d6 when he spends 1 action point. If so, apply the highest result and disregard the other rolls. A 15th-level character, for instance, gets to roll 3d6 and take the best result of the three. So, if he rolled a 1, 2, and 4, he would apply the 4 to his d20 roll.
Special Actions
A character can perform certain tasks by spending an action point. In addition to the actions described below, some prestige classes or feats (see below) might allow the expenditure of action points in order to gain or activate specific abilities, at the GM’s option.
Activate Class Ability
A character can spend 1 action point to gain another use of a class ability that has a limited number of uses per day. For example, a monk might spend an action point to gain another use of her stunning fist ability, or a paladin might spend an action point to make an additional smite attack.
Boost Defense
A character can spend 1 action point as a
free action when fighting defensively. This gives him double the normal benefits for fighting defensively for the entire round (+4
dodge bonus to AC; +6 if he has 5 or more ranks in Tumble).
Emulate Feat
At the beginning of a character’s turn, he may spend 1 action point as a
free action to gain the benefit of a feat he doesn’t have. He must meet the prerequisites of the feat. He gains the benefit until the beginning of his next turn.
Extra attack
During any round in which a character takes a full attack action, he may spend 1 action point to make an extra attack at his highest base attack bonus. Action points may be used in this way with both melee and ranged attacks.
Spell Boost
A character can spend 1 action point as a
free action to increase the effective caster level of one of his spells by 2. He must decide whether or not to spend an action point in this manner before casting the spell.
Spell Recall
Spellcasters who prepare their spells in advance can spend 1 action point to recall any spell just cast. The spell can be cast again later with no effect on other prepared spells. This use of an action point is a
free action and can only be done in the same round that the spell is cast. Spontaneous spellcasters such as sorcerers and bards can spend 1 action point to cast a spell without using one of their daily spell slots. This use of an action point is a free action and can only be done as the spell is being cast.
Stable
Any time a character is dying, he can spend 1 action point to become stable at his current hit point total.
Improving Feats
The use of action points opens up a whole range of possible feats. However, it’s easier on characters simply to improve existing feats to take advantage of action points—that way, characters needn’t spend their precious feat slots simply to gain the ability to use their action points. Below are a few examples of how action points can be used with existing feats. Unless otherwise stated, each effect requires a
free action to activate and lasts 1 round.
Blind-Fight
You can spend 1 action point to negate your miss chance for a single attack.
Combat Expertise
You can spend 1 action point to double the bonus to Armor Class granted by the feat. For example, if you take a penalty of -3 on your
attack roll, you gain a +6
dodge bonus to AC.
Dodge
You can spend 1 action point to increase the
dodge bonus granted by the feat to +2. The effect lasts for the entire encounter.
Improved Critical
You can spend 1 action point to double your critical threat range. Since two doublings equals a tripling, this benefit increases your threat range from 19-20 to 18-20, from 17-20 to 15-20, or from 15-20 to 12-20, including the effect of your Improved Critical feat. This benefit stacks with the benefit from Improved Critical, but not with other effects that increase threat range.
Improved Initiative
You can spend 1 action point to double the bonus on initiative checks granted by the feat, from +4 to +8.
Metamagic Feats
You can spend 1 action point to add the effect of any one metamagic feat that you have to a spell you are casting. The spell is cast at its normal level (without any level adjustment because of the feat) and takes no extra time to cast.
Heighten Spell automatically raises a spell’s effective level to the highest level of spell you are capable of casting. For example, if a 7th-level wizard with the Heighten Spell feat casts burning hands and spends 1 action point to heighten the spell, the spell is treated as if it were a 4th-level spell in all respects even though the wizard prepared it normally (as a 1st-level spell).
Power Attack
You can spend 1 action point to double the bonus on damage rolls granted by the feat. For example, if you take a penalty of -3 on your
attack roll, you add +6 to your damage roll.
Spell Focus
You can spend 1 action point to double the increase to save DCs granted by the feat, from +1 to +2.
Spell Penetration
You can spend 1 action point to double the bonus on
caster level checks granted by the feat, from +2 to +4. The effect lasts for the entire encounter.
