diff --git a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/misc/annotations.kt b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/misc/annotations.kt
index 206e4e000..7f53d96ce 100644
--- a/kmath-core/src/commonMain/kotlin/space/kscience/kmath/misc/annotations.kt
+++ b/kmath-core/src/commonMain/kotlin/space/kscience/kmath/misc/annotations.kt
@@ -5,5 +5,13 @@
 
 package space.kscience.kmath.misc
 
+/**
+ * Marks declarations that are still experimental in the KMath APIs, which means that the design of the corresponding
+ * declarations has open issues which may (or may not) lead to their changes in the future. Roughly speaking, there is
+ * a chance that those declarations will be deprecated in the near future or the semantics of their behavior may change
+ * in some way that may break some code.
+ */
+@MustBeDocumented
+@Retention(value = AnnotationRetention.BINARY)
 @RequiresOptIn("This API is unstable and could change in future", RequiresOptIn.Level.WARNING)
 public annotation class UnstableKMathAPI