diff --git a/platform/script-debugger/protocol/protocol-reader/src/TextOutput.kt b/platform/script-debugger/protocol/protocol-reader/src/TextOutput.kt
index 58e2e9ded441..23b1ee8b63db 100644
--- a/platform/script-debugger/protocol/protocol-reader/src/TextOutput.kt
+++ b/platform/script-debugger/protocol/protocol-reader/src/TextOutput.kt
@@ -77,8 +77,7 @@ class TextOutput(val out: StringBuilder) {
   }
 
   fun openBlock(): TextOutput {
-    openBlock(true)
-    return this
+    return openBlock(true)
   }
 
   inline fun block(addNewLine: Boolean = true, writer: () -> Unit): TextOutput {
@@ -88,16 +87,18 @@ class TextOutput(val out: StringBuilder) {
     return this
   }
 
-  fun openBlock(addNewLine: Boolean) {
+  fun openBlock(addNewLine: Boolean): TextOutput {
     space().append('{')
     if (addNewLine) {
       newLine()
     }
     indentIn()
+    return this
   }
 
-  fun closeBlock() {
+  fun closeBlock(): TextOutput {
     indentOut().newLine().append('}')
+    return this
   }
 
   fun comma() = append(',').space()
diff --git a/platform/script-debugger/protocol/protocol-reader/src/TypeWriter.kt b/platform/script-debugger/protocol/protocol-reader/src/TypeWriter.kt
index 4f7ecca46f1f..ddf40950e211 100644
--- a/platform/script-debugger/protocol/protocol-reader/src/TypeWriter.kt
+++ b/platform/script-debugger/protocol/protocol-reader/src/TypeWriter.kt
@@ -215,13 +215,13 @@ internal class TypeWriter<T>(val typeClass: Class<T>, jsonSuperClass: TypeRef<*>
           fieldLoader.valueReader.writeReadCode(classScope, false, out)
 
           if (primitiveValueName != null) {
-            out.newLine().append("else").openBlock()
+            out.closeBlock().newLine().append("else").block {
+              assignField(out, "${primitiveValueName}Type")
+              out.append("reader.peek()").newLine()
 
-            assignField(out, "${primitiveValueName}Type")
-            out.append("reader.peek()").newLine()
-
-            assignField(out, primitiveValueName)
-            out + "reader.nextString(true)"
+              assignField(out, primitiveValueName)
+              out + "reader.nextString(true)"
+            }
           }
 
           if (stopIfAllFieldsWereRead && !isTracedStop) {
diff --git a/platform/script-debugger/protocol/protocol-reader/src/Util.kt b/platform/script-debugger/protocol/protocol-reader/src/Util.kt
index 4d33a5ca045c..2f46fb112afc 100644
--- a/platform/script-debugger/protocol/protocol-reader/src/Util.kt
+++ b/platform/script-debugger/protocol/protocol-reader/src/Util.kt
@@ -18,7 +18,11 @@ val JSON_READER_PARAMETER_DEF = "$READER_NAME: $JSON_READER_CLASS_NAME"
 internal fun writeJavaTypeName(arg: Type, out: TextOutput) {
   if (arg is Class<*>) {
     val name = arg.canonicalName
-    out.append(if (name == "java.util.List") "List" else name)
+    out.append(
+        if (name == "java.util.List") "List"
+        else if (name == "java.lang.String") "String?"
+        else name
+    )
   }
   else if (arg is ParameterizedType) {
     writeJavaTypeName(arg.rawType, out)