Ajani, Valiant Protector — ruling 1

If you don’t have a creature card in your library while resolving Ajani’s second ability, you’ll reveal your library and then randomize it.

Ajani, Valiant Protector — ruling 2

The value of X for Ajani’s third ability is determined only as it resolves. The number of +1/+1 counters on the creature won’t change later if your life total changes.

Ajani, Valiant Protector : règles, fonctionnement et interactions (MTG)

Ajani, Valiant Protector 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

+2: Put two +1/+1 counters on up to one target creature. +1: Reveal cards from the top of your library until you reveal a creature card. Put that card into your hand and the rest on the bottom of your library in a random order. −11: Put X +1/+1 counters on target creature, where X is your life total. That creature gains trample until end of turn.

How it works : Ajani, Valiant Protector

Original English text — Wizards of the Coast / Scryfall

#1February 9, 2017· Wizards of the Coast
If you don’t have a creature card in your library while resolving Ajani’s second ability, you’ll reveal your library and then randomize it.
No other card is named in this ruling.
#2February 9, 2017· Wizards of the Coast
The value of X for Ajani’s third ability is determined only as it resolves. The number of +1/+1 counters on the creature won’t change later if your life total changes.
No other card is named in this ruling.

Interactions with other cards

These cards' text mentions Ajani, Valiant Protector.

Ajani's Aid

When this enchantment enters, you may search your library and/or graveyard for a card named Ajani, Valiant Protector, reveal it, and put it into your hand. If you search your library this way, shuffle. Sacrifice this enchantment: Prevent all combat damage a creature of your choice would deal this turn.