Attack Cost Rule

Update your rules folder

projects/mtg/bin/Res/sets/primitives/borderline.txt

@@ -1,4 +1,17 @@
 grade=borderline
+#planeswalker and creature attack cost...
+[card]
+name=Archangel of Tithes
+abilities=flying
+auto=this(untapped) lord(creature|opponentbattlefield) transforms((,newability[@each mycombatbegins:pay[[{1}]] name(pay 1 mana) donothing?cantattack all(this)]))
+auto=@combat(attacking) source(this):all(creature|opponentbattlefield) transforms((,newability[pay[[{1}]] name(pay 1 mana) donothing?cantblock all(this)]))
+text=Flying -- As long as Archangel of Tithes is untapped, creatures can't attack you or a planeswalker you control unless their controller pays {1} for each of those creatures. -- As long as Archangel of Tithes is attacking, creatures can't block unless their controller pays {1} for each of those creatures.
+mana={1}{W}{W}{W}
+type=Creature
+subtype=Angel
+power=3
+toughness=5
+[/card]
 [card]
 name=Autumn Willow
 abilities=opponentshroud,shroud

projects/mtg/bin/Res/sets/primitives/unsupported.txt

@@ -12123,12 +12123,6 @@ power=*
 toughness=*
 [/card]
 [card]
-name=Koskun Falls
-text=At the beginning of your upkeep, sacrifice Koskun Falls unless you tap an untapped creature you control. -- Creatures can't attack you unless their controller pays {2} for each creature he or she controls that's attacking you.
-mana={2}{B}{B}
-type=World Enchantment
-[/card]
-[card]
 name=Kozilek's Channeler
 text={T}: Add {C}{C} to your mana pool.
 mana={5}