diff --git a/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/MangaSearchQueryCapabilities.kt b/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/MangaSearchQueryCapabilities.kt
index 6551defe..f9feecb3 100644
--- a/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/MangaSearchQueryCapabilities.kt
+++ b/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/MangaSearchQueryCapabilities.kt
@@ -1,7 +1,6 @@
 package org.koitharu.kotatsu.parsers.model.search
 
 import androidx.collection.ArraySet
-import org.koitharu.kotatsu.parsers.InternalParsersApi
 import org.koitharu.kotatsu.parsers.model.search.QueryCriteria.*
 import org.koitharu.kotatsu.parsers.util.mapToSet
 
@@ -12,38 +11,35 @@ public data class MangaSearchQueryCapabilities internal constructor(
 
 	public constructor(vararg capabilities: SearchCapability) : this(ArraySet(capabilities))
 
-	@InternalParsersApi
-	public fun validate(query: MangaSearchQuery) {
+	internal fun validate(query: MangaSearchQuery) {
 		val strictFields = capabilities.filter { it.isExclusive }.mapToSet { it.field }
 		val usedStrictFields = query.criteria.mapToSet { it.field }.intersect(strictFields)
 
-		if (usedStrictFields.isNotEmpty() && query.criteria.size > 1) {
-			throw IllegalArgumentException(
-				"Query contains multiple criteria, but at least one field (${usedStrictFields.joinToString()}) does not support multiple criteria.",
-			)
+		require(usedStrictFields.isEmpty() || query.criteria.size <= 1) {
+			"Query contains multiple criteria, but at least one field (${usedStrictFields.joinToString()}) does not support multiple criteria."
 		}
-
 		for (criterion in query.criteria) {
-			val capability = capabilities.find { it.field == criterion.field }
-				?: throw IllegalArgumentException("Unsupported search field: ${criterion.field}")
+			val capability = requireNotNull(capabilities.find { it.field == criterion.field }) {
+				"Unsupported search field: ${criterion.field}"
+			}
 
-			if (criterion::class !in capability.criteriaTypes) {
-				throw IllegalArgumentException(
-					"Unsupported search criterion: ${criterion::class.simpleName} for field ${criterion.field}",
-				)
+			require(criterion::class in capability.criteriaTypes) {
+				"Unsupported search criterion: ${criterion::class.simpleName} for field ${criterion.field}"
 			}
 
 			// Ensure single value per criterion if supportMultiValue is false
 			if (!capability.isMultiple) {
 				when (criterion) {
-					is Include<*> -> if (criterion.values.size > 1)
-						throw IllegalArgumentException("Multiple values are not allowed for field ${criterion.field}")
+					is Include<*> -> require(criterion.values.size <= 1) {
+						"Multiple values are not allowed for field ${criterion.field}"
+					}
 
-					is Exclude<*> -> if (criterion.values.size > 1)
-						throw IllegalArgumentException("Multiple values are not allowed for field ${criterion.field}")
+					is Exclude<*> -> require(criterion.values.size <= 1) {
+						"Multiple values are not allowed for field ${criterion.field}"
+					}
 
-					is Range<*> -> {} // Range is always valid (from, to)
-					is Match<*> -> {} // Match always has a single value
+					is Range<*> -> Unit // Range is always valid (from, to)
+					is Match<*> -> Unit // Match always has a single value
 				}
 			}
 		}
diff --git a/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/SearchableField.kt b/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/SearchableField.kt
index d14e5c16..42e3fc40 100644
--- a/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/SearchableField.kt
+++ b/src/main/kotlin/org/koitharu/kotatsu/parsers/model/search/SearchableField.kt
@@ -19,5 +19,5 @@ public enum class SearchableField(public val type: Class<*>) {
 	CONTENT_TYPE(ContentType::class.java),
 	CONTENT_RATING(ContentRating::class.java),
 	DEMOGRAPHIC(Demographic::class.java),
-	PUBLICATION_YEAR(Int::class.java);
+	PUBLICATION_YEAR(Int::class.javaObjectType);
 }