Region Flags

A flag is a rule a region carries about what may happen inside it: whether its blocks may be broken, placed, or used, whether mobs may spawn, whether players may hurt each other. Flags are entries of their own, added to a definition's Modifiers field, so one flag entry can be shared by as many regions as need the same rule.

Add Region Block Break Modifier

Decide who may break the blocks in a region

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A region either carries a flag of a given kind, and then it decides, or it does not carry that flag, and then the next region down in priority decides instead. A region with none of the flags never decides anything for that action; it is invisible to the check, and whichever other region does carry the flag decides as if it were not there at all.

Every flag has a single Allowed field, off by default. A region carrying the flag with Allowed off blocks the action; with Allowed on it permits it, which only matters where a lower priority region would otherwise have forbidden it. On some flags that field accepts a variable, so a fact can drive it; the pages below say which.

Which flags exist

Page	Flags
Block Flags	Break, Place, Interact, Entity Interact, Bucket, Trample, Ignite
World Flags	Piston, Redstone, Fire Spread, Fluid Flow, Explosion, Mob Spawn, Mob Grief
Combat Flags	Pvp, Mob Damage, Player Damage, Entity Damage
Limits and Gaps	Where flags abstain, and what they never see

Priority

Every region has a priority. Unless the definition's Priority Override field is set, a region's priority is simply the priority of the page it is declared on. Flags have no priority of their own: they inherit whatever priority the region that lists them has, so a region's rules always move together.

Where two regions carrying the same flag overlap, the one with the higher priority decides, and the other is not consulted at all. That is how an arena inside a protected city can allow what the city forbids. Give the city a flag that denies the action, and give the arena the same kind of flag with Allowed on and a higher priority than the city's, either by raising the arena's page priority or by setting Priority Override directly on the arena's definition. Inside the arena the higher priority region wins; everywhere else in the city the lower priority region's ban still holds.

 Breaking a tie

When two overlapping regions carrying the same flag also share the same priority, one of them wins and it is always the same one, but which one is not something you can predict or read off the page. Give one of them an explicit Priority Override whenever it matters which rule applies.

What decides, and where

Flags are resolved at the thing being acted on, never at the player doing it. Breaking, placing, interacting, filling a bucket, trampling a crop and lighting a fire resolve at the target block; the combat flags resolve at the victim; a spawn resolves where the mob appears. A player camped just outside a protected region cannot reach in and act on anything inside it by aiming across the boundary.

Flags protect the place, audiences protect the player

Region Audiences covers Prevent Block Break Audience and Prevent Block Place Audience from the Basic extension. Those are about the player, wherever they are standing: put one under a Region Inside Audience and a player inside the region loses the ability to break or place blocks anywhere on the server, not only inside that region, while a player standing outside keeps mining and building into it freely.

A flag is the other way around. It does not care who the player is or where they stand; it only cares where the block is. Reach for the Basic audiences when you want to take an ability away from specific players. Reach for a flag when you want to protect the place itself from everyone, including someone who never set foot inside it.

Example: an arena inside a protected city

Region definitions and flags both live on manifest pages (see Manifest Entries).

1. On a manifest page, add a Region Block Break Modifier entry named city_no_breaking and leave Allowed off.
2. Add your city's region definition, for example a Polygon Region Definition named city_bounds walking the city walls, and add city_no_breaking to its Modifiers field.
3. Add a second Region Block Break Modifier entry named arena_breaking_allowed with Allowed on.
4. Add a Cuboid Region Definition named arena covering the arena floor, add arena_breaking_allowed to its Modifiers field, and set its Priority Override higher than city_bounds's priority.
5. Publish.

Breaking is now blocked everywhere inside city_bounds, except inside arena, where the higher priority region's flag takes over and allows it again.

To check what applies where, run /tw region flags standing in the spot in question.