Souvenir T-Shirt — ruling 1

A "Magic-branded item" is an article of clothing or wearable accessory (jewelry, etc.) that includes a Magic logo, symbols, artwork, or other brand-identifying markings. Anything that's usually paired (socks, earrings, and so on) count as one item.

Souvenir T-Shirt — ruling 2

You choose which result applies to power and which applies to toughness.

Souvenir T-Shirt — ruling 3

Each die is identified by the number of faces it has. A six-sided die is a die with six equally likely outcomes: 1, 2, 3, 4, 5, and 6. The roll must be fair. Although physical dice are recommended, digital substitutes are allowed except in cases where the physical die is required for the effect.

Souvenir T-Shirt — ruling 4

If an ability triggers "whenever you roll a die," it will trigger whenever you roll any die, including the planar die. This is a change from previous Un- rules. Some abilities use the result to determine part of the effect. If you get a non-numerical result (currently just the planar die, but the future is long), that part of the effect won't do anything.

Souvenir T-Shirt — ruling 5

Something in the game must tell you to roll a die. If you roll a die for any other reason (to simulate a coin flip, to choose pizza toppings, to create alternate timelines), that roll doesn't count.

Souvenir T-Shirt — ruling 6

Some effects may modify the result of a die roll. This may be part of the instruction to roll a die, or it may come from other cards. Anything that references the "result" of a die roll is looking for the result after these modifications.

Souvenir T-Shirt — ruling 7

If a die is rerolled, the original roll essentially never happened: it doesn't cause any abilities to trigger, and no effect that cares about die rolls will consider it.

Souvenir T-Shirt — ruling 8

Results can be numbers not ordinarily possible on a six-sided die. Spells like Scooch can change the result to 0 or 7, for example.

Souvenir T-Shirt : règles, fonctionnement et interactions (MTG)

Souvenir T-Shirt 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

Gear Up, sponsored by Wizards of the Coast — As this Equipment enters, roll two six-sided dice. For each Magic-branded item you're wearing, roll an additional six-sided die. Choose two of those results. Equipped creature gets +X/+Y, where X is the first chosen result and Y is the second. Equip

How it works : Souvenir T-Shirt

Original English text — Wizards of the Coast / Scryfall

#1October 7, 2022· Wizards of the Coast
A "Magic-branded item" is an article of clothing or wearable accessory (jewelry, etc.) that includes a Magic logo, symbols, artwork, or other brand-identifying markings. Anything that's usually paired (socks, earrings, and so on) count as one item.
No other card is named in this ruling.
#2October 7, 2022· Wizards of the Coast
You choose which result applies to power and which applies to toughness.
No other card is named in this ruling.
#3October 7, 2022· Wizards of the Coast
Each die is identified by the number of faces it has. A six-sided die is a die with six equally likely outcomes: 1, 2, 3, 4, 5, and 6. The roll must be fair. Although physical dice are recommended, digital substitutes are allowed except in cases where the physical die is required for the effect.
No other card is named in this ruling.
#4October 7, 2022· Wizards of the Coast
If an ability triggers "whenever you roll a die," it will trigger whenever you roll any die, including the planar die. This is a change from previous Un- rules. Some abilities use the result to determine part of the effect. If you get a non-numerical result (currently just the planar die, but the future is long), that part of the effect won't do anything.
No other card is named in this ruling.
#5October 7, 2022· Wizards of the Coast
Something in the game must tell you to roll a die. If you roll a die for any other reason (to simulate a coin flip, to choose pizza toppings, to create alternate timelines), that roll doesn't count.
No other card is named in this ruling.
#6October 7, 2022· Wizards of the Coast
Some effects may modify the result of a die roll. This may be part of the instruction to roll a die, or it may come from other cards. Anything that references the "result" of a die roll is looking for the result after these modifications.
No other card is named in this ruling.
#7October 7, 2022· Wizards of the Coast
If a die is rerolled, the original roll essentially never happened: it doesn't cause any abilities to trigger, and no effect that cares about die rolls will consider it.
No other card is named in this ruling.
#8October 7, 2022· Wizards of the Coast
Results can be numbers not ordinarily possible on a six-sided die. Spells like Scooch can change the result to 0 or 7, for example.
No other card is named in this ruling.