When to pass priority using scroll rack?

[Offler]

Situation:
Opponent has Trickbind, I have Scroll rack and Magus of the Future in play.

I will activate Scroll Rack (*), paying its cost
Then i remove cards from my hand, draw cards from library and arrange the exiled cards onto the library(**)

When the opponent is able to cast the trickbind? at (*) or at (**) when it is certain which card will remain on top of library?

Do i have to announce which card will be placed onto top of the library?

[majikal]

Your opponent must cast the Trickbind before you do anything with the cards in your library. Scroll Rack's ability has to resolve first, and Trickbind is kinda sorta designed to stop that from happening.

You announce ability, pay costs, put it on the stack. You have to pass priority before anything happens. Your opponent now plays Trickbind.

[Offler]

Just to find the correct principle...

All it is required from me is to:
1. Pay the costs
2. Choose the mode of spell/ability if there is any
3. Select the targets.

When opponent asks what exactly I want to do upon resolution I am allowed to keep the secret, until the spell sucessfully resolves.

Just say that i am going to put on the top of library some very needed spell and play it from the top of library rather than from hand, and opponent says that he cannot make the decision with the trickbind until he has all the information. He is not allowed to know which spell will be on top of library until ability of the Scroll rack sucessfully resolves and after that playing trickbind is just useless.

But the coin has darker side..

One of my opponents was playing White command this way:
He revealed the card from his hand asking if I react. I asked him that what mode of card is he choosing, he answered that he can keep his secret because the card has "untargeted" mode - when all permanents of some type are affected.

He targeted the Senseis Divining top, then i tapped it to save it, he argued that i had a chance to react previously, not now.

(to cdr: as i was some time ago mentioning former DCI judge who likes to cheat - thats him)

However as long I know he did not chosen mode, even target at the time when he was trying to pass the priority to me. I believe that his act of passing priority was illegal. What do you think?

[Nessaja]

It's much simpler then you make it.

Everything after the ":" is the resolution of the spell. If your opponent did not react, everything that is part of the resolution will happen. If you or your opponent don't like the outcome of the resolution of a spell then that's too bad, it's too late to react at that time.

I'm not sure what you're talking about with White Command, I guess you're talking about Austerre Command. If that's the case, your opponent has to announce what modes he chooses and then you get a chance to react. Note that Austere Command does not target.

[cdr]

One of my opponents was playing White command this way:
He revealed the card from his hand asking if I react. I asked him that what mode of card is he choosing, he answered that he can keep his secret because the card has "untargeted" mode - when all permanents of some type are affected.

He targeted the Senseis Divining top, then i tapped it to save it, he argued that i had a chance to react previously, not now.

(to cdr: as i was some time ago mentioning former DCI judge who likes to cheat - thats him)

However as long I know he did not chosen mode, even target at the time when he was trying to pass the priority to me. I believe that his act of passing priority was illegal. What do you think?

"Mode" is very specific thing - it's indicated by the words "Choose [one/two] -". The Command cycle does indeed have modes.

Modes are chosen on announcement just like targets.

If this person is actually a judge and your incident happened recently, you should PM me this person's name.