diff --git a/modules/almond-spark/src/main/scala/org/apache/spark/sql/almondinternals/NotebookSparkSessionBuilder.scala b/modules/almond-spark/src/main/scala/org/apache/spark/sql/almondinternals/NotebookSparkSessionBuilder.scala
index 15b8d56..dee223c 100644
--- a/modules/almond-spark/src/main/scala/org/apache/spark/sql/almondinternals/NotebookSparkSessionBuilder.scala
+++ b/modules/almond-spark/src/main/scala/org/apache/spark/sql/almondinternals/NotebookSparkSessionBuilder.scala
@@ -20,6 +20,8 @@ class NotebookSparkSessionBuilder(implicit
   commHandler: CommHandler
 ) extends AmmoniteSparkSessionBuilder {
 
+  override def toString = "NotebookSparkSessionBuilder"
+
   override def printLine(line: String, htmlLine: String = null): Unit =
     if (htmlLine == null)
       publish.html(line + System.lineSeparator())
diff --git a/modules/core/src/main/scala/org/apache/spark/sql/ammonitesparkinternals/AmmoniteSparkSessionBuilder.scala b/modules/core/src/main/scala/org/apache/spark/sql/ammonitesparkinternals/AmmoniteSparkSessionBuilder.scala
index 28376ac..686be87 100644
--- a/modules/core/src/main/scala/org/apache/spark/sql/ammonitesparkinternals/AmmoniteSparkSessionBuilder.scala
+++ b/modules/core/src/main/scala/org/apache/spark/sql/ammonitesparkinternals/AmmoniteSparkSessionBuilder.scala
@@ -158,6 +158,8 @@ class AmmoniteSparkSessionBuilder(implicit
   replApi: ReplAPI
 ) extends SparkSession.Builder {
 
+  override def toString = "AmmoniteSparkSessionBuilder"
+
   import AmmoniteSparkSessionBuilder.normalize
 
   def printLine(line: String, htmlLine: String = null): Unit =