diff --git a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/DataGen.kt b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/DataGen.kt
index 0be49080a..81e3b1bdd 100644
--- a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/DataGen.kt
+++ b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/DataGen.kt
@@ -528,12 +528,11 @@ object DataGen {
 		event.generator.addProvider(event.includeServer(), matterData)
 
 		val registrySetBuilder = RegistrySetBuilder()
-		val set = registrySetBuilder
 			.add(Registries.DAMAGE_TYPE, ::registerDamageTypes)
 			.add(Registries.CONFIGURED_FEATURE, ::registerConfiguredFeatures)
 			.add(Registries.PLACED_FEATURE, ::registerPlacedFeatures)
 
-		event.generator.addProvider(event.includeServer(), DatapackBuiltinEntriesProvider(event.generator.packOutput, event.lookupProvider, set, setOf(MOD_ID)))
+		event.generator.addProvider(event.includeServer(), DatapackBuiltinEntriesProvider(event.generator.packOutput, event.lookupProvider, registrySetBuilder, setOf(MOD_ID)))
 
 		registerDamageTypeTags(tagsProvider.damageTypes)
 
diff --git a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt
index a6f5ad5f6..671566490 100644
--- a/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt
+++ b/src/data/kotlin/ru/dbotthepony/mc/otm/datagen/tags/TagsProvider.kt
@@ -46,35 +46,29 @@ class TagsProvider(private val event: GatherDataEvent) {
 		inner class Appender(val tag: TagKey<T>) {
 			constructor(tag: ResourceLocation) : this(TagKey.create(registryKey, tag))
 
+			init {
+				require(tag.registry == registryKey) { "Trying to create appender for $tag inside registry $registryKey" }
+			}
+
 			private val locations by lazy { tags.computeIfAbsent(tag) { ObjectArraySet() } }
 			private val rigidLocations by lazy { rigidTags.computeIfAbsent(tag) { ObjectArraySet() } }
 			private val tagsInTags by lazy { tagInTag.computeIfAbsent(tag) { ObjectArraySet() } }
 
 			fun add(value: ResourceLocation): Appender {
-				if (!locations.add(value)) {
-					throw IllegalStateException("Tag $tag of registry $registryKey already contains $value")
-				}
-
+				check(locations.add(value)) { "Tag ${tag.location} of registry ${registryKey.location()} already contains $value" }
 				return this
 			}
 
 			fun add(value: ResourceKey<T>): Appender {
-				require(value.registry() == registryKey.location()) { "Invalid registry in provided ResourceKey: ${value.registry()} (this tag appender is for $registryKey)" }
-
-				if (!rigidLocations.add(value)) {
-					throw IllegalStateException("Tag $tag of registry ${registryKey.location()} already contains $value")
-				}
-
-				return this
+				require(value.registry() == registryKey.location()) { "Invalid registry in provided ResourceKey: ${value.registry()} (this tag appender is for ${registryKey.location()})" }
+				// check(rigidLocations.add(value)) { "Tag ${tag.location} of registry ${registryKey.location()} already contains $value" }
+				// return this
+				return add(value.location())
 			}
 
 			fun add(value: TagKey<T>): Appender {
-				require(value.registry() == registryKey.location()) { "Invalid registry in provided ResourceKey: ${value.registry()} (this tag appender is for $registryKey)" }
-
-				if (!tagsInTags.add(value)) {
-					throw IllegalStateException("Tag $tag of registry ${registryKey.location()} already contains $value")
-				}
-
+				require(value.registry() == registryKey) { "Invalid registry in provided ResourceKey: ${value.registry().location()} (this tag appender is for ${registryKey.location()})" }
+				check(tagsInTags.add(value)) { "Tag ${tag.location} of registry ${registryKey.location()} already contains $value" }
 				return this
 			}
 
@@ -128,10 +122,6 @@ class TagsProvider(private val event: GatherDataEvent) {
 		fun forge(path: String) = Appender(ResourceLocation("forge", path))
 
 		override fun addTags(provider: HolderLookup.Provider) {
-			if (tags.isEmpty()) {
-				return
-			}
-
 			for ((tag, values) in tags) {
 				val appender = tag(tag)