diff --git a/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java b/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
index 14216ac627938b..6db9d86bc1ebf4 100644
--- a/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
+++ b/src/main/java/com/google/devtools/build/lib/packages/StarlarkSemanticsOptions.java
@@ -390,7 +390,7 @@ public class StarlarkSemanticsOptions extends OptionsBase implements Serializabl
 
   @Option(
       name = "incompatible_new_actions_api",
-      defaultValue = "false",
+      defaultValue = "true",
       documentationCategory = OptionDocumentationCategory.STARLARK_SEMANTICS,
       effectTags = {OptionEffectTag.BUILD_FILE_SEMANTICS},
       metadataTags = {
diff --git a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
index 22ce113f2dac15..0f7d4de6d6450d 100644
--- a/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
+++ b/src/main/java/com/google/devtools/build/lib/syntax/StarlarkSemantics.java
@@ -236,7 +236,7 @@ public static Builder builderWithDefaults() {
           .incompatibleDisallowRuleExecutionPlatformConstraintsAllowed(false)
           .incompatibleDisallowStructProviderSyntax(false)
           .incompatibleExpandDirectories(true)
-          .incompatibleNewActionsApi(false)
+          .incompatibleNewActionsApi(true)
           .incompatibleNoAttrLicense(true)
           .incompatibleNoKwargsInBuildFiles(false)
           .incompatibleNoOutputAttrDefault(true)
diff --git a/src/main/java/com/google/devtools/build/skydoc/SkydocMain.java b/src/main/java/com/google/devtools/build/skydoc/SkydocMain.java
index d45368d92e0575..bb8a6eae87be4f 100644
--- a/src/main/java/com/google/devtools/build/skydoc/SkydocMain.java
+++ b/src/main/java/com/google/devtools/build/skydoc/SkydocMain.java
@@ -125,21 +125,21 @@
 /**
  * Main entry point for the Skydoc binary.
  *
- * <p>Skydoc generates human-readable documentation for relevant details of skylark files by
- * running a skylark interpreter with a fake implementation of the build API.</p>
+ * <p>Skydoc generates human-readable documentation for relevant details of skylark files by running
+ * a skylark interpreter with a fake implementation of the build API.
  *
  * <p>Currently, Skydoc generates documentation for skylark rule definitions (discovered by
- * invocations of the build API function {@code rule()}.</p>
+ * invocations of the build API function {@code rule()}.
+ *
+ * <p>Usage:
  *
- * <p>Usage:</p>
  * <pre>
  *   skydoc {target_skylark_file_label} {output_file} [symbol_name]...
  * </pre>
- * <p>
- *   Generates documentation for all exported symbols of the target skylark file that are
- *   specified in the list of symbol names. If no symbol names are supplied, outputs documentation
- *   for all exported symbols in the target skylark file.
- * </p>
+ *
+ * <p>Generates documentation for all exported symbols of the target skylark file that are specified
+ * in the list of symbol names. If no symbol names are supplied, outputs documentation for all
+ * exported symbols in the target skylark file.
  */
 public class SkydocMain {
 
@@ -170,6 +170,7 @@ public static void main(String[] args)
     StarlarkSemanticsOptions semanticsOptions = parser.getOptions(StarlarkSemanticsOptions.class);
     semanticsOptions.incompatibleDepsetUnion = false;
     semanticsOptions.incompatibleDisableDeprecatedAttrParams = false;
+    semanticsOptions.incompatibleNewActionsApi = false;
     SkydocOptions skydocOptions = parser.getOptions(SkydocOptions.class);
 
     String targetFileLabelString;
@@ -198,8 +199,7 @@ public static void main(String[] args)
       depRoots = ImmutableList.copyOf(skydocOptions.depRoots);
     }
 
-    Label targetFileLabel =
-        Label.parseAbsolute(targetFileLabelString, ImmutableMap.of());
+    Label targetFileLabel = Label.parseAbsolute(targetFileLabelString, ImmutableMap.of());
 
     ImmutableMap.Builder<String, RuleInfo> ruleInfoMap = ImmutableMap.builder();
     ImmutableMap.Builder<String, ProviderInfo> providerInfoMap = ImmutableMap.builder();
@@ -271,9 +271,8 @@ private static void printRuleInfos(
   }
 
   private static void printProviderInfos(
-      PrintWriter printWriter,
-      MarkdownRenderer renderer,
-      Map<String, ProviderInfo> providerInfos) throws IOException {
+      PrintWriter printWriter, MarkdownRenderer renderer, Map<String, ProviderInfo> providerInfos)
+      throws IOException {
     for (Entry<String, ProviderInfo> entry : providerInfos.entrySet()) {
       printProviderInfo(printWriter, renderer, entry.getKey(), entry.getValue());
       printWriter.println();
@@ -299,14 +298,17 @@ private static void printUserDefinedFunctions(
   }
 
   private static void printRuleInfo(
-      PrintWriter printWriter, MarkdownRenderer renderer,
-      String exportedName, RuleInfo ruleInfo) throws IOException {
+      PrintWriter printWriter, MarkdownRenderer renderer, String exportedName, RuleInfo ruleInfo)
+      throws IOException {
     printWriter.println(renderer.render(exportedName, ruleInfo));
   }
 
   private static void printProviderInfo(
-      PrintWriter printWriter, MarkdownRenderer renderer,
-      String exportedName, ProviderInfo providerInfo) throws IOException {
+      PrintWriter printWriter,
+      MarkdownRenderer renderer,
+      String exportedName,
+      ProviderInfo providerInfo)
+      throws IOException {
     printWriter.println(renderer.render(exportedName, providerInfo));
   }
 
@@ -347,14 +349,12 @@ public Environment eval(
     List<ProviderInfo> providerInfoList = new ArrayList<>();
     Environment env = recursiveEval(semantics, label, ruleInfoList, providerInfoList);
 
-    Map<BaseFunction, RuleInfo> ruleFunctions = ruleInfoList.stream()
-        .collect(Collectors.toMap(
-            RuleInfo::getIdentifierFunction,
-            Functions.identity()));
-    Map<BaseFunction, ProviderInfo> providerInfos = providerInfoList.stream()
-        .collect(Collectors.toMap(
-            ProviderInfo::getIdentifier,
-            Functions.identity()));
+    Map<BaseFunction, RuleInfo> ruleFunctions =
+        ruleInfoList.stream()
+            .collect(Collectors.toMap(RuleInfo::getIdentifierFunction, Functions.identity()));
+    Map<BaseFunction, ProviderInfo> providerInfos =
+        providerInfoList.stream()
+            .collect(Collectors.toMap(ProviderInfo::getIdentifier, Functions.identity()));
 
     // Sort the bindings so their ordering is deterministic.
     TreeMap<String, Object> sortedBindings = new TreeMap<>(env.getGlobals().getExportedBindings());
@@ -492,10 +492,11 @@ private Environment evalSkylarkBody(
    * @param providerInfoList the list of {@link ProviderInfo} objects, to which provider()
    *     invocation information will be added
    */
-  private static GlobalFrame globalFrame(List<RuleInfo> ruleInfoList,
-      List<ProviderInfo> providerInfoList) {
+  private static GlobalFrame globalFrame(
+      List<RuleInfo> ruleInfoList, List<ProviderInfo> providerInfoList) {
     TopLevelBootstrap topLevelBootstrap =
-        new TopLevelBootstrap(new FakeBuildApiGlobals(),
+        new TopLevelBootstrap(
+            new FakeBuildApiGlobals(),
             new FakeSkylarkAttrApi(),
             new FakeSkylarkCommandLineApi(),
             new FakeSkylarkNativeModuleApi(),
@@ -504,16 +505,18 @@ private static GlobalFrame globalFrame(List<RuleInfo> ruleInfoList,
             new FakeOutputGroupInfoProvider(),
             new FakeActionsInfoProvider(),
             new FakeDefaultInfoProvider());
-    AndroidBootstrap androidBootstrap = new AndroidBootstrap(new FakeAndroidSkylarkCommon(),
-        new FakeApkInfoProvider(),
-        new FakeAndroidInstrumentationInfoProvider(),
-        new FakeAndroidDeviceBrokerInfoProvider(),
-        new FakeAndroidResourcesInfoProvider(),
-        new FakeAndroidNativeLibsInfoProvider());
+    AndroidBootstrap androidBootstrap =
+        new AndroidBootstrap(
+            new FakeAndroidSkylarkCommon(),
+            new FakeApkInfoProvider(),
+            new FakeAndroidInstrumentationInfoProvider(),
+            new FakeAndroidDeviceBrokerInfoProvider(),
+            new FakeAndroidResourcesInfoProvider(),
+            new FakeAndroidNativeLibsInfoProvider());
     AppleBootstrap appleBootstrap = new AppleBootstrap(new FakeAppleCommon());
     ConfigBootstrap configBootstrap =
-        new ConfigBootstrap(new FakeConfigSkylarkCommon(), new FakeConfigApi(),
-            new FakeConfigGlobalLibrary());
+        new ConfigBootstrap(
+            new FakeConfigSkylarkCommon(), new FakeConfigApi(), new FakeConfigGlobalLibrary());
     CcBootstrap ccBootstrap = new CcBootstrap(new FakeCcModule());
     JavaBootstrap javaBootstrap =
         new JavaBootstrap(
diff --git a/src/test/java/com/google/devtools/build/lib/analysis/BuildViewTest.java b/src/test/java/com/google/devtools/build/lib/analysis/BuildViewTest.java
index 9379951222badf..ae2bab09be0907 100644
--- a/src/test/java/com/google/devtools/build/lib/analysis/BuildViewTest.java
+++ b/src/test/java/com/google/devtools/build/lib/analysis/BuildViewTest.java
@@ -448,7 +448,7 @@ public void testOutputFilterWithDebug() throws Exception {
         "java/b/rules.bzl",
         "def _impl(ctx):",
         "  print('debug in b')",
-        "  ctx.file_action(",
+        "  ctx.actions.write(",
         "    output = ctx.outputs.my_output,",
         "    content = 'foo',",
         "  )",
diff --git a/src/test/java/com/google/devtools/build/lib/query2/aquery/ActionGraphProtoOutputFormatterCallbackTest.java b/src/test/java/com/google/devtools/build/lib/query2/aquery/ActionGraphProtoOutputFormatterCallbackTest.java
index 03c944624e4fec..34092731f63be2 100644
--- a/src/test/java/com/google/devtools/build/lib/query2/aquery/ActionGraphProtoOutputFormatterCallbackTest.java
+++ b/src/test/java/com/google/devtools/build/lib/query2/aquery/ActionGraphProtoOutputFormatterCallbackTest.java
@@ -483,7 +483,7 @@ public void testCppActionTemplate_includesActionTemplateMnemonic() throws Except
         "test/a.bzl",
         "def _impl(ctx):",
         "  directory = ctx.actions.declare_directory(ctx.attr.name + \"_artifact.cc\")",
-        "  ctx.action(",
+        "  ctx.actions.run_shell(",
         "    inputs = ctx.files.srcs,",
         "    outputs = [directory],",
         "    mnemonic = 'MoveTreeArtifact',",
diff --git a/src/test/java/com/google/devtools/build/lib/rules/java/proto/SkylarkJavaLiteProtoLibraryTest.java b/src/test/java/com/google/devtools/build/lib/rules/java/proto/SkylarkJavaLiteProtoLibraryTest.java
index 302e166b904a0c..159f659333bc89 100644
--- a/src/test/java/com/google/devtools/build/lib/rules/java/proto/SkylarkJavaLiteProtoLibraryTest.java
+++ b/src/test/java/com/google/devtools/build/lib/rules/java/proto/SkylarkJavaLiteProtoLibraryTest.java
@@ -89,6 +89,8 @@ public final void setUpMocks() throws Exception {
 
   @Before
   public final void setupSkylarkRule() throws Exception {
+    setSkylarkSemanticsOptions("--incompatible_new_actions_api=false");
+
     File[] files = Runfiles.location(RULE_DIRECTORY).listFiles();
     for (File file : files) {
       scratch.file(RULE_DIRECTORY + "/" + file.getName(), Files.readAllBytes(file.toPath()));
diff --git a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
index baa1c16e36513f..b83c2bb563bf70 100644
--- a/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skylark/SkylarkRuleImplementationFunctionsTest.java
@@ -391,15 +391,6 @@ public void testCreateSpawnActionUnknownParam() throws Exception {
         "ruleContext.actions.run(outputs=[], bad_param = 'some text', executable = f)");
   }
 
-  @Test
-  public void testCreateSpawnActionNoExecutable() throws Exception {
-    SkylarkRuleContext ruleContext = createRuleContext("//foo:foo");
-    checkErrorContains(
-        ruleContext,
-        "You must specify either 'command' or 'executable' argument",
-        "ruleContext.action(outputs=[])");
-  }
-
   private Object createTestSpawnAction(SkylarkRuleContext ruleContext) throws Exception {
     return evalRuleContextCode(
         ruleContext,
diff --git a/src/test/shell/bazel/external_path_test.sh b/src/test/shell/bazel/external_path_test.sh
index 3cf8592d1b8b69..735c68c50f3247 100755
--- a/src/test/shell/bazel/external_path_test.sh
+++ b/src/test/shell/bazel/external_path_test.sh
@@ -337,8 +337,8 @@ cat $1 | tr 'a-z' 'A-Z' > $2
 EOF
   cat > rule/to_upper.bzl <<'EOF'
 def _to_upper_impl(ctx):
-  output = ctx.new_file(ctx.label.name + ".txt")
-  ctx.action(
+  output = ctx.actions.declare_file(ctx.label.name + ".txt")
+  ctx.actions.run_shell(
     inputs = ctx.files.src + ctx.files._toupper_sh,
     outputs = [output],
     command = ["/bin/sh"] + [f.path for f in ctx.files._toupper_sh] \
@@ -489,8 +489,8 @@ genrule(
 EOF
   cat > rule/to_html.bzl <<'EOF'
 def _to_html_impl(ctx):
-  output = ctx.new_file(ctx.label.name + ".html")
-  ctx.action(
+  output = ctx.actions.declare_file(ctx.label.name + ".html")
+  ctx.actions.run_shell(
     inputs = ctx.files.src + ctx.files._to_html + ctx.files._preamb + ctx.files._postamb,
     outputs = [output],
     command = ["/bin/sh"] + [f.path for f in ctx.files._to_html] \
@@ -642,8 +642,8 @@ genrule(
 EOF
   cat > rule/add_preamb.bzl <<'EOF'
 def _add_preamb_impl(ctx):
-  output = ctx.new_file(ctx.label.name + ".txt")
-  ctx.action(
+  output = ctx.actions.declare_file(ctx.label.name + ".txt")
+  ctx.actions.run_shell(
     inputs = ctx.files.src + ctx.files._add_preamb + ctx.files._preamb,
     outputs = [output],
     command = ["/bin/sh"] + [f.path for f in ctx.files._add_preamb] \
diff --git a/src/test/shell/integration/aquery_test.sh b/src/test/shell/integration/aquery_test.sh
index 150f7eee43524f..3a6d8ae3395eef 100755
--- a/src/test/shell/integration/aquery_test.sh
+++ b/src/test/shell/integration/aquery_test.sh
@@ -251,7 +251,7 @@ bar_aspect = aspect(implementation = _aspect_impl,
 )
 
 def _bar_impl(ctx):
-    ctx.file_action(content = "hello world", output = ctx.outputs.out)
+    ctx.actions.write(content = "hello world", output = ctx.outputs.out)
     return struct(files = depset(transitive = [dep[DummyProvider].dummies for dep in ctx.attr.deps]))
 
 bar_rule = rule(
@@ -798,7 +798,7 @@ function test_aquery_cpp_action_template_treeartifact_output() {
   cat > "$pkg/a.bzl" <<'EOF'
 def _impl(ctx):
   directory = ctx.actions.declare_directory(ctx.attr.name + "_artifact.cc")
-  ctx.action(
+  ctx.actions.run_shell(
     inputs = ctx.files.srcs,
     outputs = [directory],
     mnemonic = 'MoveTreeArtifact',
diff --git a/src/test/shell/integration/implicit_dependency_reporting_test.sh b/src/test/shell/integration/implicit_dependency_reporting_test.sh
index 842b65df54cf83..07a826e3413ff5 100755
--- a/src/test/shell/integration/implicit_dependency_reporting_test.sh
+++ b/src/test/shell/integration/implicit_dependency_reporting_test.sh
@@ -65,8 +65,8 @@ test_custom_message() {
   touch WORKSPACE
   cat > rule.bzl <<'EOF'
 def _rule_impl(ctx):
-  out = ctx.new_file(ctx.label.name + ".txt")
-  ctx.action(
+  out = ctx.actions.declare_file(ctx.label.name + ".txt")
+  ctx.actions.run_shell(
     inputs = ctx.files._data,
     outputs = [out],
     command = ["cp"] + [f.path for f in ctx.files._data] + [out.path],