diff --git a/gradle.properties b/gradle.properties
index cf958a6e..bfec8541 100644
--- a/gradle.properties
+++ b/gradle.properties
@@ -5,7 +5,7 @@ org.gradle.jvmargs=-Xmx1G
 	# check these on https://fabricmc.net/use
     # or better: https://modmuss50.me/fabric.html
 	minecraft_version=20w18a
-	yarn_mappings=20w18a+build.3
+	yarn_mappings=20w18a+build.9
 	loader_version=0.8.2+build.194
 
 # Mod Properties
diff --git a/src/main/java/carpet/fakes/SpawnHelperInnerInterface.java b/src/main/java/carpet/fakes/SpawnHelperInnerInterface.java
new file mode 100644
index 00000000..d993f5e4
--- /dev/null
+++ b/src/main/java/carpet/fakes/SpawnHelperInnerInterface.java
@@ -0,0 +1,8 @@
+package carpet.fakes;
+
+import net.minecraft.class_5263;
+
+public interface SpawnHelperInnerInterface
+{
+    class_5263 getPotentialCalculator();
+}
diff --git a/src/main/java/carpet/mixins/SpawnHelperInnerMixin.java b/src/main/java/carpet/mixins/SpawnHelperInnerMixin.java
index 2e8af0d4..8007b44a 100644
--- a/src/main/java/carpet/mixins/SpawnHelperInnerMixin.java
+++ b/src/main/java/carpet/mixins/SpawnHelperInnerMixin.java
@@ -1,7 +1,9 @@
 package carpet.mixins;
 
+import carpet.fakes.SpawnHelperInnerInterface;
 import carpet.utils.SpawnReporter;
 import it.unimi.dsi.fastutil.objects.Object2IntMap;
+import net.minecraft.class_5263;
 import net.minecraft.entity.EntityCategory;
 import net.minecraft.world.SpawnHelper;
 import org.spongepowered.asm.mixin.Final;
@@ -14,12 +16,14 @@ import org.spongepowered.asm.mixin.injection.callback.CallbackInfoReturnable;
 // temporary mixin until naming for spawnhelper gets fixed.
 
 @Mixin(SpawnHelper.class_5262.class)
-public class SpawnHelperInnerMixin
+public class SpawnHelperInnerMixin implements SpawnHelperInnerInterface
 {
     @Shadow @Final private int field_24394;
 
     @Shadow @Final private Object2IntMap<EntityCategory> field_24395;
 
+    @Shadow @Final private class_5263 field_24396;
+
     @Inject(method = "method_27826", at = @At("HEAD"), cancellable = true)
     private void changeMobCaps(EntityCategory entityCategory, CallbackInfoReturnable<Boolean> cir)
     {
@@ -28,4 +32,12 @@ public class SpawnHelperInnerMixin
         cir.setReturnValue(field_24395.getInt(entityCategory) < i);
     }
 
+    @Override
+    public class_5263 getPotentialCalculator()
+    {
+        return field_24396;
+    }
+
+
+
 }
diff --git a/src/main/java/carpet/script/CarpetExpression.java b/src/main/java/carpet/script/CarpetExpression.java
index e129026d..1299a7f4 100644
--- a/src/main/java/carpet/script/CarpetExpression.java
+++ b/src/main/java/carpet/script/CarpetExpression.java
@@ -1,10 +1,11 @@
 package carpet.script;
 
 import carpet.CarpetServer;
+import carpet.fakes.BiomeArrayInterface;
 import carpet.fakes.ChunkTicketManagerInterface;
 import carpet.fakes.MinecraftServerInterface;
-import carpet.fakes.BiomeArrayInterface;
 import carpet.fakes.ServerChunkManagerInterface;
+import carpet.fakes.SpawnHelperInnerInterface;
 import carpet.fakes.StatTypeInterface;
 import carpet.fakes.ThreadedAnvilChunkStorageInterface;
 import carpet.helpers.FeatureGenerator;
@@ -110,6 +111,7 @@ import net.minecraft.util.math.BlockBox;
 import net.minecraft.util.math.Vec3d;
 import net.minecraft.util.math.Vec3i;
 import net.minecraft.util.registry.Registry;
+import net.minecraft.world.SpawnHelper;
 import net.minecraft.world.poi.PointOfInterest;
 import net.minecraft.world.poi.PointOfInterestStorage;
 import net.minecraft.world.poi.PointOfInterestType;
@@ -1294,6 +1296,23 @@ public class CarpetExpression
             return (_c, _t) -> ret;
         });
 
+        this.expr.addLazyFunction("spawn_potential", -1, (c, t, lv) ->
+        {
+            CarpetContext cc = (CarpetContext)c;
+            BlockArgument locator = BlockArgument.findIn(cc, lv, 0);
+            BlockPos pos = locator.block.getPos();
+            double required_charge = 1;
+            if (lv.size() > locator.offset)
+                required_charge = NumericValue.asNumber(lv.get(locator.offset).evalValue(c)).getDouble();
+            SpawnHelper.class_5262 charger = cc.s.getWorld().getChunkManager().method_27908();
+            if (charger == null) return LazyValue.NULL;
+            Value ret = new NumericValue(
+                    ((SpawnHelperInnerInterface)charger).getPotentialCalculator().
+                            method_27832(pos, required_charge )
+            );
+            return (_c, _t) -> ret;
+        });
+
     }
 
     private static String getScoreboardKeyFromValue(Value keyValue)