diff --git a/core/src/mindustry/mod/ContentParser.java b/core/src/mindustry/mod/ContentParser.java
index b604ce9cd6..7f5c86d086 100644
--- a/core/src/mindustry/mod/ContentParser.java
+++ b/core/src/mindustry/mod/ContentParser.java
@@ -357,6 +357,15 @@ public class ContentParser{
     Content currentContent;
 
     private Json parser = new Json(){
+        @Override
+        protected <T> Class<T> resolveClass(String className){
+            if(allowClassResolution){
+                return super.resolveClass(className);
+            }else{
+                throw new SerializationException("Resolving arbitrary classes (" + className + ") is not allowed. Use short names for classes only (without the package prefix).");
+            }
+        }
+
         @Override
         public <T> T readValue(Class<T> type, Class elementType, JsonValue jsonData, Class keyType){
             T t = internalRead(type, elementType, jsonData, keyType);
diff --git a/core/src/mindustry/mod/ContentPatcher.java b/core/src/mindustry/mod/ContentPatcher.java
index 620fb07145..7e535891dd 100644
--- a/core/src/mindustry/mod/ContentPatcher.java
+++ b/core/src/mindustry/mod/ContentPatcher.java
@@ -375,7 +375,7 @@ public class ContentPatcher{
                     try{
                         setter.get(parser.getJson().readValue(metadata.type, metadata.elementType, jsv));
                     }catch(Throwable e){
-                        warn("Failed to read value @.@ = @: @ (type = @ elementType = @)\n@", object, field, value, e.getMessage(), metadata.type, metadata.elementType, Strings.getStackTrace(e));
+                        warn("Failed to read value @.@ = @: (type = @ elementType = @)\n@", object, field, value, metadata.type, metadata.elementType, Strings.getSimpleMessages(e));
                     }
                    parser.listeners.pop();
                 }else{
diff --git a/gradle.properties b/gradle.properties
index 124d10b5a8..cbf61d9303 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -26,4 +26,4 @@ org.gradle.caching=true
 org.gradle.internal.http.socketTimeout=100000
 org.gradle.internal.http.connectionTimeout=100000
 android.enableR8.fullMode=false
-archash=c8f3bd901b
+archash=75fffa01c8
diff --git a/tests/src/test/java/PatcherTests.java b/tests/src/test/java/PatcherTests.java
index a88fa262c0..ece3b1d86e 100644
--- a/tests/src/test/java/PatcherTests.java
+++ b/tests/src/test/java/PatcherTests.java
@@ -1,5 +1,6 @@
 import arc.struct.*;
 import mindustry.*;
+import mindustry.ai.*;
 import mindustry.content.*;
 import mindustry.entities.abilities.*;
 import mindustry.entities.bullet.*;
@@ -266,6 +267,19 @@ public class PatcherTests{
         assertEquals(0, Blocks.grass.attributes.get(Attribute.heat));
     }
 
+    @Test
+    void testNoResolution() throws Exception{
+        String name = Pathfinder.class.getCanonicalName();
+
+        Vars.state.patcher.apply(Seq.with("""
+        block.conveyor.lastConfig: {
+            class: %theClass%
+        }
+        """.replace("%theClass%", name)));
+
+        assertEquals(1, Vars.state.patcher.patches.first().warnings.size);
+    }
+
     @Test
     void testSetMultiAdd() throws Exception{
         Vars.state.patcher.apply(Seq.with("""