Pacification Array — ruling 1

Players may respond to Pacification Array’s ability by activating an ability of the target permanent if that ability’s timing permissions allow it. Players may also respond by activating abilities or casting spells whose costs include tapping the target permanent.

Pacification Array — ruling 2

Once a player has activated an ability with {T} in its cost, Pacification Array can’t be used to undo or counter that ability.

Pacification Array — ruling 3

If you want to stop someone from attacking with a creature by using Pacification Array’s ability, you must do so before attackers are declared. You can’t wait until after attackers are declared and then try to use it to make a creature stop attacking. Note that your opponent can’t start declaring attackers without letting you use your Pacification Array.

Pacification Array : règles, fonctionnement et interactions (MTG)

Pacification Array is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

, : Tap target artifact or creature.

How it works : Pacification Array

Original English text — Wizards of the Coast / Scryfall

#1February 9, 2017· Wizards of the Coast
Players may respond to Pacification Array’s ability by activating an ability of the target permanent if that ability’s timing permissions allow it. Players may also respond by activating abilities or casting spells whose costs include tapping the target permanent.
No other card is named in this ruling.
#2February 9, 2017· Wizards of the Coast
Once a player has activated an ability with in its cost, Pacification Array can’t be used to undo or counter that ability.
No other card is named in this ruling.
#3February 9, 2017· Wizards of the Coast
If you want to stop someone from attacking with a creature by using Pacification Array’s ability, you must do so before attackers are declared. You can’t wait until after attackers are declared and then try to use it to make a creature stop attacking. Note that your opponent can’t start declaring attackers without letting you use your Pacification Array.
No other card is named in this ruling.