World Flags

World flags control the environment, mob spawning, and natural events within regions.

Flag	Bit	Default	Description
passive-entity-spawn	1	Allow	Passive mobs (animals) spawn naturally
hostile-entity-spawn	2	Allow	Hostile mobs (monsters) spawn naturally
entity-grief	4	Deny	Entities (except creepers) damage blocks
entity-damage	8	Deny	Entities attack each other
leaves-decay	16	Allow	Leaves decay naturally
fire-spread	32	Deny	Fire spreads to other blocks
liquid-flow	64	Deny	Water/lava flows into the region from outside
explosion-damage	128	Deny	Explosions damage blocks
wither-damage	256	Deny	Wither boss destroys blocks
wilderness-pistons	512	Deny	Pistons outside push blocks into region
wilderness-dispensers	1024	Deny	Dispensers outside dispense into region
wilderness-minecarts	2048	Deny	Minecarts from outside enter region
plant-growth	4096	Allow	Crops and saplings grow
grass-growth	8192	Allow	Grass spreads
sculk-spread	16384	Allow	Sculk spreads from shriekers
player-glowing	32768	Allow	Players have glowing effect
snow-melting	65536	Allow	Snow melts
ice-melting	131072	Allow	Ice melts
snowman-trails	262144	Allow	Snow golems leave snow trails
windcharge-burst	524288	Deny	Wind charges burst on impact
copper-golems-interaction	1048576	—	Deprecated — do not use
wars	2097152	Deny	Region can be targeted for war
projectiles	4194304	Deny	Projectiles (from non-player sources)
weather-snow	8388608	Allow	Snow forms during weather in cold biomes

Spawner Exclusion

In flags.yml, you can configure whether mobs from spawners are ignored by spawn flags:

flags-configuration:
  exclude-spawners: true

When true, spawner-spawned mobs are not blocked by the passive/hostile spawn flags.