diff --git a/buildSrc/src/main/kotlin/BuildInfo.kt b/buildSrc/src/main/kotlin/BuildInfo.kt
index 1b168360..90ae7639 100644
--- a/buildSrc/src/main/kotlin/BuildInfo.kt
+++ b/buildSrc/src/main/kotlin/BuildInfo.kt
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -368,7 +368,7 @@ open class BuildInfo(private val project: Project) {
     // allow -DcommitId=abc123 for build environments that don't have git.
     System.getProperty("commitId").let { if (it != null) return@lazy it }
     // only run command once per build invocation
-    if (project === project.rootProject) {
+    if (project.path == project.rootProject.path) {
       val process =
         ProcessBuilder()
           .command("git", "rev-parse", "--short", "HEAD")
diff --git a/gradle/wrapper/gradle-wrapper.jar b/gradle/wrapper/gradle-wrapper.jar
index 1b33c55b..d997cfc6 100644
Binary files a/gradle/wrapper/gradle-wrapper.jar and b/gradle/wrapper/gradle-wrapper.jar differ
diff --git a/gradle/wrapper/gradle-wrapper.properties b/gradle/wrapper/gradle-wrapper.properties
index 6a38a8ce..8e61ef12 100644
--- a/gradle/wrapper/gradle-wrapper.properties
+++ b/gradle/wrapper/gradle-wrapper.properties
@@ -1,7 +1,7 @@
 distributionBase=GRADLE_USER_HOME
 distributionPath=wrapper/dists
-distributionSha256Sum=a17ddd85a26b6a7f5ddb71ff8b05fc5104c0202c6e64782429790c933686c806
-distributionUrl=https\://services.gradle.org/distributions/gradle-9.1.0-bin.zip
+distributionSha256Sum=2ab2958f2a1e51120c326cad6f385153bb11ee93b3c216c5fccebfdfbb7ec6cb
+distributionUrl=https\://services.gradle.org/distributions/gradle-9.4.1-bin.zip
 networkTimeout=10000
 validateDistributionUrl=true
 zipStoreBase=GRADLE_USER_HOME
diff --git a/gradlew b/gradlew
index 23d15a93..739907df 100755
--- a/gradlew
+++ b/gradlew
@@ -1,7 +1,7 @@
 #!/bin/sh
 
 #
-# Copyright © 2015-2021 the original authors.
+# Copyright © 2015 the original authors.
 #
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
@@ -57,7 +57,7 @@
 #       Darwin, MinGW, and NonStop.
 #
 #   (3) This script is generated from the Groovy template
-#       https://github.com/gradle/gradle/blob/HEAD/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
+#       https://github.com/gradle/gradle/blob/2d6327017519d23b96af35865dc997fcb544fb40/platforms/jvm/plugins-application/src/main/resources/org/gradle/api/internal/plugins/unixStartScript.txt
 #       within the Gradle project.
 #
 #       You can find Gradle at https://github.com/gradle/gradle/.
@@ -114,7 +114,6 @@ case "$( uname )" in                #(
   NONSTOP* )        nonstop=true ;;
 esac
 
-CLASSPATH="\\\"\\\""
 
 
 # Determine the Java command to use to start the JVM.
@@ -172,7 +171,6 @@ fi
 # For Cygwin or MSYS, switch paths to Windows format before running java
 if "$cygwin" || "$msys" ; then
     APP_HOME=$( cygpath --path --mixed "$APP_HOME" )
-    CLASSPATH=$( cygpath --path --mixed "$CLASSPATH" )
 
     JAVACMD=$( cygpath --unix "$JAVACMD" )
 
@@ -212,7 +210,6 @@ DEFAULT_JVM_OPTS='"-Xmx64m" "-Xms64m"'
 
 set -- \
         "-Dorg.gradle.appname=$APP_BASE_NAME" \
-        -classpath "$CLASSPATH" \
         -jar "$APP_HOME/gradle/wrapper/gradle-wrapper.jar" \
         "$@"
 
diff --git a/gradlew.bat b/gradlew.bat
index db3a6ac2..c4bdd3ab 100644
--- a/gradlew.bat
+++ b/gradlew.bat
@@ -70,11 +70,10 @@ goto fail
 :execute
 @rem Setup the command line
 
-set CLASSPATH=
 
 
 @rem Execute Gradle
-"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -classpath "%CLASSPATH%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
+"%JAVA_EXE%" %DEFAULT_JVM_OPTS% %JAVA_OPTS% %GRADLE_OPTS% "-Dorg.gradle.appname=%APP_BASE_NAME%" -jar "%APP_HOME%\gradle\wrapper\gradle-wrapper.jar" %*
 
 :end
 @rem End local scope for the variables with windows NT shell
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/AnalyzeImportsTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/AnalyzeImportsTask.java
index b29e0e9a..ea0cec9c 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/AnalyzeImportsTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/AnalyzeImportsTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -19,12 +19,14 @@ import java.io.File;
 import org.gradle.api.file.RegularFileProperty;
 import org.gradle.api.provider.Property;
 import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Optional;
 import org.gradle.api.tasks.OutputFile;
 import org.pkl.cli.CliImportAnalyzer;
 import org.pkl.cli.CliImportAnalyzerOptions;
 
+@CacheableTask
 public abstract class AnalyzeImportsTask extends ModulesTask {
   @OutputFile
   @Optional
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/BasePklTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/BasePklTask.java
index 1a68dbff..f585ee10 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/BasePklTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/BasePklTask.java
@@ -36,11 +36,14 @@ import org.gradle.api.provider.MapProperty;
 import org.gradle.api.provider.Property;
 import org.gradle.api.provider.Provider;
 import org.gradle.api.provider.ProviderFactory;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFile;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.Internal;
 import org.gradle.api.tasks.Optional;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.TaskAction;
 import org.pkl.commons.cli.CliBaseOptions;
 import org.pkl.core.evaluatorSettings.Color;
@@ -48,6 +51,7 @@ import org.pkl.core.util.LateInit;
 import org.pkl.core.util.Nullable;
 import org.pkl.gradle.utils.PluginUtils;
 
+@CacheableTask
 public abstract class BasePklTask extends DefaultTask {
   private static final String TRUFFLE_USE_FALLBACK_RUNTIME_FLAG = "truffle.UseFallbackRuntime";
 
@@ -67,6 +71,7 @@ public abstract class BasePklTask extends DefaultTask {
   public abstract MapProperty<String, String> getExternalProperties();
 
   @InputFiles
+  @PathSensitive(PathSensitivity.ABSOLUTE)
   public abstract ConfigurableFileCollection getModulePath();
 
   @Internal
@@ -79,6 +84,7 @@ public abstract class BasePklTask extends DefaultTask {
 
   @InputFile
   @Optional
+  @PathSensitive(PathSensitivity.ABSOLUTE)
   public Provider<File> getSettingsModuleFile() {
     return getParsedSettingsModule()
         .map(
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/CodeGenTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/CodeGenTask.java
index 5903acd0..e23ec9e4 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/CodeGenTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/CodeGenTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -18,10 +18,12 @@ package org.pkl.gradle.task;
 import org.gradle.api.file.DirectoryProperty;
 import org.gradle.api.provider.MapProperty;
 import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Optional;
 import org.gradle.api.tasks.OutputDirectory;
 
+@CacheableTask
 public abstract class CodeGenTask extends ModulesTask {
   @OutputDirectory
   public abstract DirectoryProperty getOutputDir();
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/EvalTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/EvalTask.java
index bd89d387..42184c6e 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/EvalTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/EvalTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -24,6 +24,7 @@ import org.gradle.api.file.FileCollection;
 import org.gradle.api.file.RegularFileProperty;
 import org.gradle.api.provider.Property;
 import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Internal;
 import org.gradle.api.tasks.Optional;
@@ -32,6 +33,7 @@ import org.gradle.api.tasks.OutputFiles;
 import org.pkl.cli.CliEvaluator;
 import org.pkl.cli.CliEvaluatorOptions;
 
+@CacheableTask
 public abstract class EvalTask extends ModulesTask {
 
   // not tracked because it might contain placeholders
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/JavaCodeGenTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/JavaCodeGenTask.java
index 83ba3ac3..ec69ec7a 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/JavaCodeGenTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/JavaCodeGenTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,11 +17,13 @@ package org.pkl.gradle.task;
 
 import java.io.File;
 import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Optional;
 import org.pkl.codegen.java.CliJavaCodeGenerator;
 import org.pkl.codegen.java.CliJavaCodeGeneratorOptions;
 
+@CacheableTask
 public abstract class JavaCodeGenTask extends CodeGenTask {
   @Input
   public abstract Property<Boolean> getGenerateGetters();
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/KotlinCodeGenTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/KotlinCodeGenTask.java
index 5adac69b..83e2b5cb 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/KotlinCodeGenTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/KotlinCodeGenTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,10 +17,12 @@ package org.pkl.gradle.task;
 
 import java.io.File;
 import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.pkl.codegen.kotlin.CliKotlinCodeGenerator;
 import org.pkl.codegen.kotlin.CliKotlinCodeGeneratorOptions;
 
+@CacheableTask
 public abstract class KotlinCodeGenTask extends CodeGenTask {
   @Input
   public abstract Property<Boolean> getGenerateKdoc();
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/ModulesTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/ModulesTask.java
index c4ff215e..a511b686 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/ModulesTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/ModulesTask.java
@@ -30,16 +30,20 @@ import org.gradle.api.file.FileCollection;
 import org.gradle.api.provider.ListProperty;
 import org.gradle.api.provider.Property;
 import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.Internal;
 import org.gradle.api.tasks.Optional;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.TaskAction;
 import org.pkl.commons.cli.CliBaseOptions;
 import org.pkl.core.evaluatorSettings.Color;
 import org.pkl.core.util.Pair;
 import org.pkl.gradle.utils.PluginUtils;
 
+@CacheableTask
 public abstract class ModulesTask extends BasePklTask {
   // We expose the contents of this property as task inputs via the sourceModuleFiles
   // and sourceModuleUris properties. We cannot use two separate properties because
@@ -49,6 +53,7 @@ public abstract class ModulesTask extends BasePklTask {
   public abstract ListProperty<Object> getSourceModules();
 
   @InputFiles
+  @PathSensitive(PathSensitivity.ABSOLUTE)
   public abstract ListProperty<File> getTransitiveModules();
 
   private final Map<List<Object>, Pair<List<File>, List<URI>>> parsedSourceModulesCache =
@@ -63,6 +68,7 @@ public abstract class ModulesTask extends BasePklTask {
 
   // We use @InputFiles and FileCollection here to ensure that file contents are tracked.
   @InputFiles
+  @PathSensitive(PathSensitivity.ABSOLUTE)
   public FileCollection getSourceModuleFiles() {
     return getProject().files(getParsedSourceModules().map(it -> it.first));
   }
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/PkldocTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/PkldocTask.java
index 8db69d65..40748411 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/PkldocTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/PkldocTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -17,11 +17,13 @@ package org.pkl.gradle.task;
 
 import org.gradle.api.file.DirectoryProperty;
 import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.OutputDirectory;
 import org.pkl.doc.CliDocGenerator;
 import org.pkl.doc.CliDocGeneratorOptions;
 
+@CacheableTask
 public abstract class PkldocTask extends ModulesTask {
   @OutputDirectory
   public abstract DirectoryProperty getOutputDir();
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectPackageTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectPackageTask.java
index 5997119c..0281c143 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectPackageTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectPackageTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024-2025 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -27,6 +27,8 @@ import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.Internal;
 import org.gradle.api.tasks.Optional;
 import org.gradle.api.tasks.OutputDirectory;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.gradle.api.tasks.UntrackedTask;
 import org.pkl.cli.CliProjectPackager;
 import org.pkl.commons.cli.CliTestOptions;
@@ -34,6 +36,7 @@ import org.pkl.commons.cli.CliTestOptions;
 @UntrackedTask(because = "Output names are known only after execution")
 public abstract class ProjectPackageTask extends BasePklTask {
   @InputFiles
+  @PathSensitive(PathSensitivity.ABSOLUTE)
   public abstract ConfigurableFileCollection getProjectDirectories();
 
   @Internal
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectResolveTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectResolveTask.java
index 4ea0d0a6..7d497196 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectResolveTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/ProjectResolveTask.java
@@ -1,5 +1,5 @@
 /*
- * Copyright © 2024 Apple Inc. and the Pkl project authors. All rights reserved.
+ * Copyright © 2024-2026 Apple Inc. and the Pkl project authors. All rights reserved.
  *
  * Licensed under the Apache License, Version 2.0 (the "License");
  * you may not use this file except in compliance with the License.
@@ -23,10 +23,14 @@ import java.util.stream.Collectors;
 import org.gradle.api.InvalidUserDataException;
 import org.gradle.api.file.ConfigurableFileCollection;
 import org.gradle.api.provider.Provider;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.InputFiles;
 import org.gradle.api.tasks.Internal;
+import org.gradle.api.tasks.PathSensitive;
+import org.gradle.api.tasks.PathSensitivity;
 import org.pkl.cli.CliProjectResolver;
 
+@CacheableTask
 public abstract class ProjectResolveTask extends BasePklTask {
   @Internal
   public abstract ConfigurableFileCollection getProjectDirectories();
@@ -34,6 +38,7 @@ public abstract class ProjectResolveTask extends BasePklTask {
   // Only the `PklProject` files matter for creating PklProject.deps.json files.
   // Otherwise, these tasks can be considered up to date.
   @InputFiles
+  @PathSensitive(PathSensitivity.ABSOLUTE)
   public Provider<List<File>> getProjectPklFiles() {
     return getProjectDirectories()
         .getElements()
diff --git a/pkl-gradle/src/main/java/org/pkl/gradle/task/TestTask.java b/pkl-gradle/src/main/java/org/pkl/gradle/task/TestTask.java
index 59fdb1b9..409692e6 100644
--- a/pkl-gradle/src/main/java/org/pkl/gradle/task/TestTask.java
+++ b/pkl-gradle/src/main/java/org/pkl/gradle/task/TestTask.java
@@ -18,12 +18,14 @@ package org.pkl.gradle.task;
 import java.io.PrintWriter;
 import org.gradle.api.file.DirectoryProperty;
 import org.gradle.api.provider.Property;
+import org.gradle.api.tasks.CacheableTask;
 import org.gradle.api.tasks.Input;
 import org.gradle.api.tasks.Optional;
 import org.gradle.api.tasks.OutputDirectory;
 import org.pkl.cli.CliTestRunner;
 import org.pkl.commons.cli.CliTestOptions;
 
+@CacheableTask
 public abstract class TestTask extends ModulesTask {
   @Optional
   @OutputDirectory