It boils down to the six primary abilities (str, dex, con, etc.), hp, and three types of defenses. The HP and defenses are generated directly from the primary stats. All your stats start between 0-3 and you add them directly to your rolls which are made with FATE dice (or "fudge" dice, as they are sometimes called). The dice are 6-sided with the faces being -1, -1, 0, 0, 1, 1, the average being 0. All rolls are made by throwing four dice, so the result ranges from -4 to 4.
https://fate-srd.com/fate-core...math-behind-the-dice
Every action will come down to rolling the dice, adding your stat and comparing it to a DC or AC. If you exceed the DC or def, you succeed. Higher rolls will yield better results.
To use the example of attacking, you can use any stat to attack as long as you can make a case for it (my goal is to not say 'no' so much that other players might step in and say, "I don't think that makes sense"). Hitpoints are a composite of physical, mental, and emotional health or fortitude, as well as luck. So, you can attack by swinging a sword or intimidating someone. Once their hp is depleted, they are defeated, the manner of which is defined by the 'killing' blow. So, you if you intimidated someone, they give up, or run away. If you persuade someone, they cooperate, if you hit them they may be killed or knocked out, etc.
Let's say you are fighting someone who has the following stats:
Str: 3
Dex: 0
Con: 1
Int: 0
Wis: 1
Cha: 2
HP: 6 (str+dex+con+int+wis+cha)
Physical AC: 3 (str+dex)
Magical AC: 1 (con+int)
Emotional AC: 3 (wis+cha)
You decide to attack with a punch, so you would roll and add your str and compare that to their Physical AC (PAC). If you roll a total of 4, you will damage the guy for 1 point of damage (roll - PAC). That's pretty much the end of the story.
Every level you can add +1 to one of your stats, with some limitations, namely no more that +1 to any stat every four levels. So, after 20 levels, the most you can add to any stat is +5 (once each between lvls 1-4, 5-8, 9-12, 13-16, 17-20).
"Classes" will not exist and will be defined more by play and items. If you want to be a fighter, wear armor and carry weapons. If you want to be a mage find wands and spellbooks. My conception of spells is that if you have a spellbook or wand that lets you cast something like Prestidigitation you can attempt anything with that basic flavor. Or with a wand of Fire, you can shoot firebolts, or cause something to erupt, or heat metal by poking it, or whatever. Just roll, add int and "poof". In the case of direct damage roll will be compared to Magical AC (MAC). In other cases, like causing something to ignite, a DC will have to be defined, something like 0 for a stack of dry papers and 5 for a stack of wet branches.
Items will provide a bonus to certain types of rolls or ACs and will look something like this:
Dagger
+1 str* or dex*
Magic Battle Axe [pre-req: Str 1]
+3 str*
Helmet
+1 PAC (Physical AC)
Breastplate [pre-req: Str 2]
+2 PAC
Wand of Fire [pre-req: Int 2]
+1 int fire spells
Allows user to cast a fire spell 1/day
Holy Symbol [pre-req Wis 2]
+1 Wis*
+2 Wis vs undead
Allows user to cast light spell 3/day
Lockpicks [pre-req: Dex 1]
+1 Dex to open locks
Allows user to attempt to open locks
*would only apply to rolls that make sense, so for weapons it would always apply to attacks, but an axe would provide this bonus for chopping a door, a dagger to prying something up or cutting a rope or something. A pickaxe might provide its bonus to climbing or digging, etc. Anything that you can reasonably justify. They do not modify your base stats which then roll into hp and defenses.
The idea is to make everything more simple. One roll and a few numbers.
Part of the FATE system also involves things like creating advantages, which boils down to changing the environment for later exploitation (setting fire to a room, creating difficult terrain, blinding someone or making them dizzy, etc). The general idea is that creating some favorable condition will allow you or someone else to apply a +2 to a roll that would reasonably benefit from that condition. Because the distribution of FATE dice at the extremes become very improbable, a +2 is a big deal in cases where rolling a 3 or 4 will just barely let you succeed, which incentivizes alternate actions.
For instance, if you are fighting something with defenses in the 5 range and you can only muster a +3 to your rolls, you only damage when rolling a 3 or higher (6.17% chance). If you can give yourself or someone else a +2, your odds improve by about 32%. The things you do to improve conditions can have any conceivable difficulty, so you look to the environment or situation to find things that are relatively easy to do.
I think a shortcut would be something like trying to trip an opponent rather than damage them directly, so, maybe I would use only their dex for a DC instead fo their PAC (str+dex). Being prone would give someone else a +2 to their roll. Generally speaking, such bonuses can only be exploited once or twice before going away. I would also say that opponents would get wise to certain maneuvers, so you couldn't spam the same actions without the DC rolling in their normal defense.
An analog to a mental/emotional attack would be instead of doing 'intimidation' damage you try to goad someone to distract them, thereby attack only cha and providing a subsequent +2 for someone else.
Instead of generating or picking scores we can also do something like Race/class/background, each of which provides a set bonus (like con for dwarves or dex for elves) and a free stat that you can put anywhere.
Or roll 1d4-1 and re-roll the set if it doesn't add up to at least 8 (which is a little less than just picking). Otherwise, something like an array of 3,2,2,1,1,0.
If we do this we can introduce 'stunts' which would be a bonus you can use on a specific type of action a limited number of times. In the FATE system these are based on character aspects which might be described as, "smashing is always an option". So if you do something with that basic sentiment, which I would extend to "smashing a dialogue, or smashing a polite dinner party" in the sense that you do something unexpected and confrontational or destructive in the generic sense, then you can apply that bonus. The idea is to live out your character traits.
There is a little more nuance with fate points, but I don't think we need to incorporate that.
