Firkraag, Cunning Instigator — ruling 1

An ability that looks for whether a creature "had to attack" checks to see if there were any requirements to attack that were applying to that particular creature at the time it was declared as an attacker. If an ability required that creature's controller to attack rather than the creature itself (such as that of Trove of Temptation), that creature dealing combat damage won't cause Firkraag's last ability to trigger, even if it was the only creature that player could have attacked with to meet the requirement.

Firkraag, Cunning Instigator : règles, fonctionnement et interactions (MTG)

Firkraag, Cunning Instigator 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

Flying, haste Whenever one or more Dragons you control attack an opponent, goad target creature that player controls. Whenever a creature deals combat damage to one of your opponents, if that creature had to attack this combat, you put a +1/+1 counter on Firkraag and you draw a card.

How it works : Firkraag, Cunning Instigator

Original English text — Wizards of the Coast / Scryfall

#1June 10, 2022· Wizards of the Coast
An ability that looks for whether a creature "had to attack" checks to see if there were any requirements to attack that were applying to that particular creature at the time it was declared as an attacker. If an ability required that creature's controller to attack rather than the creature itself (such as that of Trove of Temptation), that creature dealing combat damage won't cause Firkraag's last ability to trigger, even if it was the only creature that player could have attacked with to meet the requirement.
No other card is named in this ruling.