Let's say someone creates the Aspect Out of ammo by running everywhere, making the other character fire all his bullets.
Can this character still fire until someone compels Out of ammo?
Is it the GM responsibility to compel here? Or should we simply provide him a FATE point directly (when he receive the aspect) as it limits his action anyway?
Will he get a Fate point every turn ?
How do you handle such cases?
The specifics are going to depend on your implementation of Fate, but in Standard Fate (and Fate Core), when you Create an Advantage (or create a temporary aspect), you get a free invocation. I'm going to quote the rule from Fate Core:
Free invocations work like normal ones except in two ways: no fate points are exchanged, and you can stack them with a normal invocation for a better bonus. With a free invocation and paying a fate point on the same aspect, a +2 bonus can become a +4, one reroll could become two rerolls, or you can add +4 to another character’s roll or passive opposition instead of +2. You can also stack multiple free invocations together.
After you’ve used your free invocation, if the aspect in question is still around, you can keep invoking it by spending fate points.
Via Jadasc, I checked Rob Donoghue's excellent post on Hard vs. Soft Tags. There's also a tangential reference to Out of Ammo on the Fate SRD. With this info, and a discussion on G+ to frame it, the following example comes to light.
When you put Out of Ammo on the target using the Create an Advantage move, the target is now out of ammo. There's no need for invocation, the aspect existing makes that a fact. (Nor, IMO, is there a need for a compel... you could compel the implicit Using a Gun aspect for a fate point to make it run dry instead of using Create Advantage to make the Out of Ammo aspect. But you specifically proposed using Create Advantage here.)
The target now needs to remove Out of Ammo and, if he's reasonably equipped with a spare clip, that would be an automatic action. Reloading, after all, is easy. It looks like your Create Advantage didn't do you any good...
It's THEN that the Out of Ammo could be free-invoked, to create a Fair (+2) difficulty where otherwise no difficulty would have existed. Now to reload, the target must do an Overcome.
Alternately, if reloading would already be difficult for some reason (say the gun in question is a revolver or we've already established that the target has no spare clips just loose rounds), so an Overcome against a difficulty was already going to be necessary. The free invocation could be used to make it 2 points more difficult.
You could use the free invocation as a bonus to your next defense claiming that the effort to reload cost him time.
There is also another alternative for creating the aspect that is overlooked. If a roll is missed, that doesn't necessarily mean failure. A failed roll can mean success with a cost, so you can also suggest the temporary aspect as a cost of success.
If a character has an aspect that relates to the limited ammunition in his weapon, then that could be tagged in order to make the character run out of ammunition. In that case, the exchange of fate points would occur as normal.
TL;DR - for your particular case, no invocation is required, the target is Out of Ammo. No Fate points are exchanged. He also doesn't get a fate point each turn he is Out of Ammo, though if anyone does compel the aspect while it exists for another effect that is not a Free Invocation, the Fate point exchange occurs as normal.
The summary:
Using the most recent version of the FATE Core Rules, this falls under the "create aspect" version of the Create Advantage action (p.136, the 3/18/13 draft). Once the Aspect is applied, it's true until it goes away.
How long that takes depends on the success of your roll: on a tie, the aspect goes away after the first invocation. On a success, it lasts until it's removed, and you get one free invocation of it. On a success with style, you get two free invocations. On a failure, either the aspect doesn't go on, or it goes on but you don't get to take advantage of it.
And, as if by magic, Evil Hat has posted an article at FateRPG.com that addresses this very issue. The opening premise, which is cited as a fundamental building block of FATE CORE, is that aspects remain true whether invoked or not.
Can this character still fire until someone compels Out of ammo?
No. The aspect became true the minute it was created.
Is it the GM responsibility to compel here? Or should we simply provide him a FATE point directly (when he receive the aspect) as it limits his action anyway?
No. A compel means that a new interesting thing happened because of an existing aspect. Out of ammo is actually a hard one to compel because usually nothing new will happen as a result of running out of bullets (you're out of bullets, the fact that you can't shoot now is mundane), but here is an admittedly bad example:
You're now out of ammo so it makes sense that this is when your opponent would finally get the backup he's been holding out for (and just for completeness sake) d*** your luck.
Will he get a Fate point every turn ?
Not unless you're adding a new element each turn that occurs as a result of him being out of ammo and makes his life harder
How do you handle such cases?
Player B announces "my character is going to shoot Player A's Character The relevant rolls happen and he succeeds. Player A takes the stress from the attack.
Player A announces "My character is going to hop around like a frog on crack while he's being shot at in an attempt to make Player B's character run out of bullets." This is a contested roll Player B uses his gun skill to defend because of his ability to conserve ammo and his self discipline in shooting. The relevant rolls happen and Player A succeeds. Player B's Character now has the aspect out of ammo.
GM announces to Player B "You're out of ammunition and can't use your gun anymore until you fix that.
Note that no Fate Points exchanged hands
