Rule evolution
Rule 508.3a
Earliest archived Rules release: 2017-08-25 · 1 wording revision · 0 renumberings
Added508.3aDetails
An ability that reads “Whenever [a creature] attacks, . . .” triggers if that creature is declared as an attacker. Similarly, “Whenever [a creature] attacks [a player or planeswalker], . . .” triggers if that creature is declared as an attacker attacking that player or planeswalker. Such abilities won’t trigger if a creature is put onto the battlefield attacking.
Wording changed508.3aDetails
An ability that reads "Whenever [a creature] attacks, . . ." triggers if that creature is declared as an attacker. Similarly, "Whenever [a creature] attacks [a player, planeswalker, or
planeswalkerbattle], . . ." triggers if that creature is declared as an attacker attacking that player orplaneswalkerpermanent. Such abilities won't trigger if a creature is put onto the battlefield attacking.