diff --git a/src/main/kotlin/ru/dbotthepony/mc/otm/capability/matter/ReplicationTask.kt b/src/main/kotlin/ru/dbotthepony/mc/otm/capability/matter/ReplicationTask.kt
index d7682e9f0..feb080e75 100644
--- a/src/main/kotlin/ru/dbotthepony/mc/otm/capability/matter/ReplicationTask.kt
+++ b/src/main/kotlin/ru/dbotthepony/mc/otm/capability/matter/ReplicationTask.kt
@@ -23,6 +23,12 @@ data class ReplicationTask(
 	val finished: Int,
 	val required: Int
 ) {
+	init {
+		require(inProgress >= 0) { "Invalid inProgress value: $inProgress"}
+		require(finished >= 0) { "Invalid finished value: $finished"}
+		require(required >= 0) { "Invalid required value: $required"}
+	}
+
 	val total get() = inProgress + finished + required
 
 	fun matchId(other: ReplicationTask): Boolean {