diff --git a/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala b/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala
index 1f911e2..e62b257 100644
--- a/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala
+++ b/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala
@@ -8,7 +8,7 @@
 class AkkaZioJsonSerializer[T <: AnyRef](
     override val identifier: Int,
     manifestDiscriminator: T => String
-)(using JsonCodec[T])(using ClassTag[T])
+)(using JsonCodec[T])(using ct: ClassTag[T])
     extends SerializerWithStringManifest:
 
   override def manifest(o: AnyRef): String =
@@ -16,7 +16,8 @@
       case p: T => manifestDiscriminator(p)
       case _ =>
         throw IllegalArgumentException(
-          s"Invalid object to serialize, expecting ProofEvent, got: ${o}"
+          s"Invalid object to serialize, expecting ${ct.runtimeClass
+            .getSimpleName()}, got: ${o}"
         )
 
   override def toBinary(o: AnyRef): Array[Byte] =
@@ -24,7 +25,8 @@
       case p: T => p.toJson.getBytes("UTF-8")
       case _ =>
         throw IllegalArgumentException(
-          s"Invalid object to serialize, expecting ProofEvent, got: ${o}"
+          s"Invalid object to serialize, expecting ${ct.runtimeClass
+            .getSimpleName()}, got: ${o}"
         )
 
   override def fromBinary(o: Array[Byte], manifest: String): AnyRef =
@@ -32,6 +34,6 @@
     json.fromJson[T] match
       case Left(t) =>
         throw IllegalStateException(
-          s"Unable to deserialize ProofEvent from $json: $t"
+          s"Unable to deserialize ${ct.runtimeClass.getSimpleName()} from $json: $t"
         )
       case Right(e) => e

diff --git a/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala b/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala
index 1f911e2..e62b257 100644
--- a/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala
+++ b/akka-persistence/src/main/scala/iw/akka/AkkaZioJsonSerializer.scala
@@ -8,7 +8,7 @@
 class AkkaZioJsonSerializer[T <: AnyRef](
     override val identifier: Int,
     manifestDiscriminator: T => String
-)(using JsonCodec[T])(using ClassTag[T])
+)(using JsonCodec[T])(using ct: ClassTag[T])
     extends SerializerWithStringManifest:
 
   override def manifest(o: AnyRef): String =
@@ -16,7 +16,8 @@
       case p: T => manifestDiscriminator(p)
       case _ =>
         throw IllegalArgumentException(
-          s"Invalid object to serialize, expecting ProofEvent, got: ${o}"
+          s"Invalid object to serialize, expecting ${ct.runtimeClass
+            .getSimpleName()}, got: ${o}"
         )
 
   override def toBinary(o: AnyRef): Array[Byte] =
@@ -24,7 +25,8 @@
       case p: T => p.toJson.getBytes("UTF-8")
       case _ =>
         throw IllegalArgumentException(
-          s"Invalid object to serialize, expecting ProofEvent, got: ${o}"
+          s"Invalid object to serialize, expecting ${ct.runtimeClass
+            .getSimpleName()}, got: ${o}"
         )
 
   override def fromBinary(o: Array[Byte], manifest: String): AnyRef =
@@ -32,6 +34,6 @@
     json.fromJson[T] match
       case Left(t) =>
         throw IllegalStateException(
-          s"Unable to deserialize ProofEvent from $json: $t"
+          s"Unable to deserialize ${ct.runtimeClass.getSimpleName()} from $json: $t"
         )
       case Right(e) => e
diff --git a/core/shared/src/main/scala/works/iterative/core/service/IdGenerator.scala b/core/shared/src/main/scala/works/iterative/core/service/IdGenerator.scala
index f905eba..1779da3 100644
--- a/core/shared/src/main/scala/works/iterative/core/service/IdGenerator.scala
+++ b/core/shared/src/main/scala/works/iterative/core/service/IdGenerator.scala
@@ -4,4 +4,7 @@
 
 /** Generator of unique IDs of a given type */
 trait IdGenerator[A]:
+  self =>
   def nextId: UIO[A]
+  def map[B](f: A => B): IdGenerator[B] = new IdGenerator[B]:
+    def nextId: UIO[B] = self.nextId.map(f)