diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/extension/PaperweightCoreExtension.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/extension/PaperweightCoreExtension.kt
index d386ee1e6..a725e68ef 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/extension/PaperweightCoreExtension.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/extension/PaperweightCoreExtension.kt
@@ -79,4 +79,6 @@ abstract class PaperweightCoreExtension @Inject constructor(objects: ObjectFacto
     fun updatingMinecraft(action: Action<UpdatingMinecraftExtension>) {
         action.execute(updatingMinecraft)
     }
+
+    val validateATs: Property<Boolean> = objects.property<Boolean>().convention(false)
 }
diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/CoreTasks.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/CoreTasks.kt
index 776db9975..6a30dd86d 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/CoreTasks.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/CoreTasks.kt
@@ -112,6 +112,7 @@ class CoreTasks(
         atFile.set(mergePaperATs.flatMap { it.outputFile })
         ats.jstClasspath.from(project.configurations.named(MACHE_MINECRAFT_LIBRARIES_CONFIG))
         ats.jst.from(project.configurations.named(JST_CONFIG))
+        validateATs.set(project.coreExt.validateATs)
     }
 
     val extractMacheSources by tasks.registering(ExtractMinecraftSources::class) {
diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/MinecraftPatchingTasks.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/MinecraftPatchingTasks.kt
index 8de9acb5a..0bb22cfc0 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/MinecraftPatchingTasks.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/taskcontainers/MinecraftPatchingTasks.kt
@@ -30,6 +30,7 @@ import io.papermc.paperweight.core.tasks.patching.ApplyFilePatches
 import io.papermc.paperweight.core.tasks.patching.ApplyFilePatchesFuzzy
 import io.papermc.paperweight.core.tasks.patching.FixupFilePatches
 import io.papermc.paperweight.core.tasks.patching.RebuildFilePatches
+import io.papermc.paperweight.core.util.coreExt
 import io.papermc.paperweight.tasks.*
 import io.papermc.paperweight.util.*
 import io.papermc.paperweight.util.constants.*
@@ -171,6 +172,7 @@ class MinecraftPatchingTasks(
             atFile.set(mergeCollectedAts.flatMap { it.outputFile })
             ats.jst.from(project.configurations.named(JST_CONFIG))
             ats.jstClasspath.from(project.configurations.named(MACHE_MINECRAFT_LIBRARIES_CONFIG))
+            validateATs.set(project.coreExt.validateATs)
         }
 
         applySourcePatches.configure {
diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupForkMinecraftSources.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupForkMinecraftSources.kt
index 673a0b94d..362c32322 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupForkMinecraftSources.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupForkMinecraftSources.kt
@@ -59,6 +59,9 @@ abstract class SetupForkMinecraftSources : JavaLauncherTask() {
     @get:Optional
     abstract val atFile: RegularFileProperty
 
+    @get:Input
+    abstract val validateATs: Property<Boolean>
+
     @get:Optional
     @get:InputDirectory
     abstract val libraryImports: DirectoryProperty
@@ -86,6 +89,7 @@ abstract class SetupForkMinecraftSources : JavaLauncherTask() {
                 outputDir.path,
                 atFile.path,
                 atWorkingDir.path,
+                validate = validateATs.get(),
             )
             commitAndTag(git, "ATs", "${identifier.get()} ATs")
         }
diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupMinecraftSources.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupMinecraftSources.kt
index 70110a9c3..3262c5da8 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupMinecraftSources.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/SetupMinecraftSources.kt
@@ -69,6 +69,10 @@ abstract class SetupMinecraftSources : JavaLauncherZippedTask() {
     @get:Input
     abstract val oldPaperCommit: Property<String>
 
+    @get:Optional
+    @get:Input
+    abstract val validateATs: Property<Boolean>
+
     @get:Nested
     val ats: ApplySourceATs = objects.newInstance()
 
@@ -182,6 +186,7 @@ abstract class SetupMinecraftSources : JavaLauncherZippedTask() {
                 outputPath,
                 atFile.path,
                 atWorkingDir.path,
+                validate = validateATs.get(),
             )
             if (!oldPaperCommit.isPresent) {
                 commitAndTag(git, "ATs", "paper ATs")
diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/patching/RebuildFilePatches.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/patching/RebuildFilePatches.kt
index 68c016b1d..82cb14178 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/patching/RebuildFilePatches.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/tasks/patching/RebuildFilePatches.kt
@@ -258,6 +258,7 @@ abstract class RebuildFilePatches : JavaLauncherTask() {
             at,
             temporaryDir.toPath().resolve("jst_work"),
             singleFile = true,
+            validate = false,
         )
         println("NEW: " + decomp.readText())
     }
diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/util/ApplySourceATs.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/util/ApplySourceATs.kt
index b19114435..dc6cd8d89 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/util/ApplySourceATs.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/core/util/ApplySourceATs.kt
@@ -53,6 +53,7 @@ abstract class ApplySourceATs {
         atFile: Path,
         workDir: Path,
         singleFile: Boolean = false,
+        validate: Boolean,
     ) {
         workDir.deleteRecursive()
         workDir.createDirectories()
@@ -61,7 +62,7 @@ abstract class ApplySourceATs {
             workDir,
             workDir.resolve("log.txt"),
             jvmArgs = listOf("-Xmx${memory.get()}"),
-            args = jstArgs(input, output, atFile, singleFile).toTypedArray()
+            args = jstArgs(input, output, atFile, singleFile, validate).toTypedArray()
         )
     }
 
@@ -70,8 +71,10 @@ abstract class ApplySourceATs {
         outputDir: Path,
         atFile: Path,
         singleFile: Boolean = false,
+        validate: Boolean,
     ): List<String> {
         val format = if (singleFile) "FILE" else "FOLDER"
+        val validation = if (validate) "ERROR" else "LOG"
         return listOf(
             "--in-format=$format",
             "--out-format=$format",
@@ -79,7 +82,7 @@ abstract class ApplySourceATs {
             "--access-transformer=$atFile",
             "--access-transformer-inherit-method=true",
             "--hidden-prefix=.git",
-            // "--access-transformer-validation=ERROR",
+            "--access-transformer-validation=$validation",
             *jstClasspath.files.map { "--classpath=${it.absolutePath}" }.toTypedArray(),
             inputDir.absolutePathString(),
             outputDir.absolutePathString(),
diff --git a/paperweight-core/src/main/kotlin/io/papermc/paperweight/patcher/extension/PaperweightPatcherExtension.kt b/paperweight-core/src/main/kotlin/io/papermc/paperweight/patcher/extension/PaperweightPatcherExtension.kt
index 18fbc9591..bf374a7bf 100644
--- a/paperweight-core/src/main/kotlin/io/papermc/paperweight/patcher/extension/PaperweightPatcherExtension.kt
+++ b/paperweight-core/src/main/kotlin/io/papermc/paperweight/patcher/extension/PaperweightPatcherExtension.kt
@@ -36,6 +36,7 @@ abstract class PaperweightPatcherExtension @Inject constructor(private val objec
 
     val gitFilePatches: Property<Boolean> = objects.property<Boolean>().convention(false)
     val filterPatches: Property<Boolean> = objects.property<Boolean>().convention(true)
+    val validateATs: Property<Boolean> = objects.property<Boolean>().convention(false)
 
     val upstreams: NamedDomainObjectContainer<UpstreamConfig> = objects.domainObjectContainer(UpstreamConfig::class) {
         objects.newInstance(it, true)