I just want to verify I'm looking at "as foretold" properly.

As foretold has 3 counters on it. I got to play monastery mentor. My opponent has:

1. trinishphere in play - I have to pay 3 mana
2. sphere of resistance in play - I have to pay 1 mana

I go to play paradoxical outcome with 4 counters on AF. My opponent has

1. trinisphere in play - I pay 3 mana
2. sphere of resistance in play - 1 pay 1 mana
3. thorn/thalia - I pay 1 mana

I have 1 more counters on AF and want to play gitaxian probe but my opponent has

1. trinisphere in play - can I pay 2 life for 1 of the 3 mana I have to pay if I announce I am using AF to play probe? (I'm pretty sure no)
2. sphere of resistance in play - I just pay 1 mana and like the last question, can I pay life for it?

I have 5 counters on as foretold. I play snapcaster mage targeting force of will in my graveyard. I can use AF for the FoW and pay no mana, correct?

Thanks for the clarifications.

@Khahan

A1: Yes, you have to pay 3 for Trinisphere.
A2: Yes, you have to pay 1 for Sphere of Resistance.

B1: Yes, you have to pay 3 for Trinisphere.
B2: Yes, you have to pay 1 for Sphere of Resistance.
B3: Yes, you have to pay 1 for Thalia or Thorn of Amethyst.

C1: You must spend at least 3 mana no matter what. You cannot pay 2 life because you are casting the spell for a cost other than it's casting cost and so can't also pay it;s casting cost in addition to that alternative cost. Incidentally if you were just casting Gitaxian Probe from your hand you may also pay 2 life if you want but you cannot pay less than 3 mana even in that case. If you wanted to pay 2 life you will still pay 3 mana on top of the two life when casting it from your hand without using As Foretold.
C2: You must spend at least 1 mana. You may spend only one mana and two life or you may spend two mana, one of which is blue. Your choice.

No, you cannot replace the flashback cost for a card using As Foretold. You may only replace the casting cost of a card using As Foretold. Flashing back a card is an ability that allows you to cast an enabled instant or sorcery from your graveyard whereas casting a spell is a special action. If you were targeting the Force of Will using a Jace, Vryn's Prodigy activation you would be able to cast it for free because that ability allows you to cast the card using any available means rather than giving the card flashback.

I think MTGO does not handle phrexian mana correctly with Trinisphere, so if you are going to play online, it might not work as intended.

The other night I could swear I saw Soly cast Dismember under Trini for just 1 colorless and 4 life.

C1: Are you 100% positive? I thought they changed this a while back to count paying 2 life for probe counted as paying mana so you'd only need 2 more trinisphere. You are paying 1 phyrexian mana by paying 2 life but its still 1 mana.

From gitaxian probe rulings I found this:
"As you cast a spell or activate an activated ability with one or more Phyrexian mana symbols in its cost, you choose how to pay for each Phyrexian mana symbol at the same time you would choose modes or choose a value for X."

At EE6 in Baltimore I was discussing this with one of the floor judges and he explained that they consider the 2 life cost like a mode of payment, but whether you pay mana or life you are still paying 1 with regard to trinisphere. So even paying the life trinisphere sees you paying 1 and only taxes 2 more on.

good catch on the flashback. As I was trying to parse these scenarios out in my head I thought of flashback being an alternate cost so it wouldn't apply then completely missed that SCM gives a card flashback. But thanks for the catching the spirit of the question too and a full answer on it.

@Khahan they changed how Convoke works to line it up with how Delve works, in that both count as "aternate ways to pay mana" but Phyrexian mana doesn't actually count as "mana payed" as far as Trinisphere is concerned. I hate the ruling but that is how it is.

@H. said in As Foretold rules clarification:

@Khahan they changed how Convoke works to line it up with how Delve works, in that both count as "aternate ways to pay mana" but Phyrexian mana doesn't actually count as "mana payed" as far as Trinisphere is concerned. I hate the ruling but that is how it is.

So convoke and delve both help meet trinisphere's requirement but phyrexian mana doesn't? No wonder I wasn't following what the judge was trying to tell me that day.

Thank you both for the answers on these questions.

@Khahan that is correct. Intuition would probably lead most to assume that Phyrexian Mana works the same as Convoke and Delve, but it doesn't actually. Indeed, I think even MTGO "thinks" this way, which I'm sure leads to even more confusion from players (and probably even some Judges).

@Aaron-Patten nailed it.

@H This is an MTGO bug. As a reminder to @MSolymossy and others, intentionally exploiting bugs in tournaments can result in a ban - it happened to the player who decided to submit a deck with Gleemox in a Vintage Daily. I'm not trying to say there was intent by anyone, just educating people on what can happen on MTGO.

@ChubbyRain I honestly don't think he knew the correct ruling and when the program let him do it he just did. I was about to respond in chat, but was cooking dinner and not in position to type.

Apparently the bug has been around for over 2 years, from a quick Google search. You'd think they'd correct it already...but what I am talking about...

@H. I agree with you that it's not intuitive or even counterintuitive which is why players and judges have had issues with this ruling for as long as I've played Vintage. It's just to caution anyone who finds out about this bug and thinks it's ok to exploit it. As for MTGO...yeah...right?...sigh

@ChubbyRain frankly it would probably be easier to change the game rules to match MTGO than the reverse, which is absurd but true...

@ChubbyRain I actually did NOT know that was a bug. I tried it because I saw it, and it made some sense to me that maybe Phyrexian Mana covered the mana cost.

Rest assure I will never do that again, as I don't ever want to play MTGO in a way I could NOT play in Paper.

@H. This is interesting. I thought that Convoke and Delve costs were "alternate costs" and thus didn't fulfill the Trinisphere requirement of having to "pay at least 3" for everything. I'm sure not saying you're wrong, but I'd really appreciate a pointer to an official ruling considering the Trinisphere is notoriously one of the strangest cards ever. If you don't have a pointer handy, I understand. my google-fu is generally not too bad once I know that I should be looking for something. Still, if you do have a pointer, it could save me some flailing around.
Thanks,
Paul

@prn "702.65b The delve ability isn’t an additional or alternative cost and applies only after the total cost of the spell with delve is determined."

"702.50b The convoke ability isn’t an additional or alternative cost and applies only after the total cost of the spell with convoke is determined."

The key here is that both apply after total cost is determined. Trinisphere usually functions to essentially be the final arbiter on what total cost can be at a minimum, but since both Delve and Convoke apply after total cost is determined, Trini has no power there.

Phyrixian mana, however, is a choice made before total cost and therefor is in the demesnes of Trinisphere.

@prn Well, Dang! I have found some sources that refer to Convoke and Delve as cost reduction, but that seems to be clearly incorrect so I won't even link to those. I find other sources like http://mtg.gamepedia.com/Convoke or http://www.mtgthesource.com/forums/showthread.php?28957-trinisphere-and-omniscience that refer to Convoke of Delve as a "method of payment." Even magicjudges.org says "We can pay using Improvise, Convoke, or Delve after activating mana abilities as part of paying costs."

OTOH, the actual text in the comprehensive rules says:
702.50 Convoke
702.50a Convoke is a static ability that functions while the spell with convoke is on the stack.
"Convoke" means "For each colored mana in this spell’s total cost, you may tap an untapped creature of that color you control rather than pay that mana. For each generic mana in this spell’s total cost, you may tap an untapped creature you control rather than pay that mana." The convoke ability isn’t an additional or alternative cost and applies only after the total cost of the spell with convoke is determined.

The corresponding definition of Delve at 702.65 also refers to exiling cards from the graveyard rather than paying mana.

So I still don't see that I have an actual official ruling to the effect that Convoke (or Delve or Improvise) is a way of paying the costs so much as something you do "rather than" paying costs.

Even though the Comp rules say that Convoke (and same for Delve or Improvise) "isn’t an additional or alternative cost" the wording of "rather than" still makes it some kind of "alternative" according to the normal meaning of the word "alternative". That's just what "alternative" means -- something that is "rather than" something else.

I'm still looking, but so far, none of the places I'm finding explanations of how these abilities work with Trinisphere, for example, are "official", or at least not actually WOTC sites. When it comes down to it, I'm uncomfortable relying on anything other than WOTC for an "official" ruling. (Regardless of whether "alternative" as used in the official rules does or does not correspond to "normal" English.)

@H. I guess I was composing my later post with references an all while you posted your response. I sort of see the point of what you say. It does make sense. My problem is that a whole lot of other things that I thought made sense have turned out not to be the way things work according to the official rulings. I'll live with your explanation, but I'd just feel more comfortable if WOTC actually included a concrete example like that in their specific ruling, e.g., on gatherer.
Oh well, I rarely get everything I want.
Thanks,
Paul

@prn the issue with some of the "rulings" (which usually are not rulings at all, but rather are just examples) is that they can mislead people in some cases, since they don't explain why something is as it is.

I think a key to your understanding is to check out the comprehensive rules section that details the actual steps to "cast a spell." (601.2a-i)

When we consider that Trinisphere's effect will take place in 601.2f, that is, the step in which we are determining the spell's total cost, but Delve and Convoke apply in step 601.2g, because they are not "alternative costs" they are an alternative way to pay mana for a spell with that ability.

So, Delve and Convoke function in step 601.2g which, being after Trinisphere's effect is checked in step 601.2f, the key final sentence of that rule comes into play, "Then the resulting total cost becomes “locked in.” If effects would change the total cost after this time, they have no effect." There is no recursive check, once in step g, we never go back.

Is it intuitive? Not really, but it's just how it is.

EDIT: Here is a link to the current and correct rules document (third party ones are often outdated and wrong): http://media.wizards.com/2017/downloads/MagicCompRules_20170605.txt

The reason Convoke and Delve pay for Trinisphere and other things do not is simply because Convoke and Delve are specifically written as exceptions to Trinisphere. Your confusion is well-founded.

@prn Delve used to function as cost reduction but it was changed around Khans. The current rules are below.

From Dig through Time:

Delve (Each card you exile from your graveyard while casting this spell pays for 1.)

From Gitaxian Probe

(Phyrexian Blue can be paid with either Blue or 2 life.)

Trinisphere cares about how much mana is paid for a spell, and the way Delve and Convoke are worded, removing a card or tapping a creature counts as paying mana. Phyrexian mana contains "or" so you are given the option of paying mana, which obviously satisfies 3Ball, or paying life, which does not. Alternate costs are paid instead of the spell's mana cost. You chose at the beginning whether or not you are going to pay 3UU of Remove a Blue Card and pay 1 life for your Force of Will. Delve, Convoke, and Phyrexian mana are not alternate costs, which is why with Snapcaster Mage , which grants Flashback equal to the spell's mana cost, you can use Delve, Convoke, and Phyrexian mana to pay for the Flashback.

Thanks, guys. Especially H. for the link to the current comp rules. The set of rules I linked to was from WOTC, but a year plus old.

Cutlex says "Convoke and Delve are specifically written as exceptions to Trinisphere." Huh? The word "specifically", I guess, could have either the meaning that the definitions of Convoke and Delve actually reference Trinisphere by name, which they manifestly do not, or possibly that the writers had Trinisphere in mind when they wrote those definitions. I'm not sure how we would know the latter.

Also thanks to ChubbyRain for the further explanations. The Dig Through Time reminder text, though, just goes to illustrate why I continue to feel uneasy. That says, "(Each card you exile from your graveyard while casting this spell pays for 1.)" (Aside: How do you do blockquotes on this forum software? ) But the CR says:"you may exile a card from your graveyard rather than pay that mana.”

I know I'm just quibbling now. I agree we've established the correct answer to the interaction of Delve and Convoke with Trinisphere, but in a game where the comprehensive rules run to a couple of hundred pages, you'd think they would try to get their wording consistent. I guess I'm just feeling grumpy. I'll try to behave.

Anyway, thanks to everyone for your efforts to educate me.