Decaying Time Loop — ruling 1

Casting a card by using its retrace ability works just like casting any other spell, with two exceptions: You're casting it from your graveyard rather than your hand, and you must discard a land card in addition to any other costs.

Decaying Time Loop — ruling 2

A retrace card cast from your graveyard follows the normal timing rules for its card type.

Decaying Time Loop — ruling 3

When a retrace spell you cast from your graveyard resolves, fails to resolve, or is countered, it's put back into your graveyard. You may use the retrace ability to cast it again.

Decaying Time Loop — ruling 4

If the active player casts a spell that has retrace, that player may cast that card again after it resolves, before another player can remove the card from the graveyard. The active player has priority after the spell resolves, so they can immediately cast a new spell. Since casting a card with retrace from the graveyard moves that card onto the stack, no one else would have the chance to affect it while it's still in the graveyard.

Decaying Time Loop : règles, fonctionnement et interactions (MTG)

Decaying Time Loop 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

Discard all the cards in your hand, then draw that many cards. Retrace (You may cast this card from your graveyard by discarding a land card in addition to paying its other costs.)

How it works : Decaying Time Loop

Original English text — Wizards of the Coast / Scryfall

#1October 13, 2023· Wizards of the Coast
Casting a card by using its retrace ability works just like casting any other spell, with two exceptions: You're casting it from your graveyard rather than your hand, and you must discard a land card in addition to any other costs.
No other card is named in this ruling.
#2October 13, 2023· Wizards of the Coast
A retrace card cast from your graveyard follows the normal timing rules for its card type.
No other card is named in this ruling.
#3October 13, 2023· Wizards of the Coast
When a retrace spell you cast from your graveyard resolves, fails to resolve, or is countered, it's put back into your graveyard. You may use the retrace ability to cast it again.
No other card is named in this ruling.
#4October 13, 2023· Wizards of the Coast
If the active player casts a spell that has retrace, that player may cast that card again after it resolves, before another player can remove the card from the graveyard. The active player has priority after the spell resolves, so they can immediately cast a new spell. Since casting a card with retrace from the graveyard moves that card onto the stack, no one else would have the chance to affect it while it's still in the graveyard.
No other card is named in this ruling.