diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionValue.java
index 8e47a39..7116a0a 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ActionExecutionValue.java
@@ -70,12 +70,8 @@
     }
 
     for (Map.Entry<Artifact, TreeArtifactValue> tree : treeArtifactData.entrySet()) {
-      TreeArtifactValue treeArtifact = tree.getValue();
-      if (TreeArtifactValue.OMITTED_TREE_MARKER.equals(treeArtifact)) {
-        continue;
-      }
       for (Map.Entry<TreeFileArtifact, FileArtifactValue> file :
-          treeArtifact.getChildValues().entrySet()) {
+          tree.getValue().getChildValues().entrySet()) {
         // We should only have RegularFileValue instances in here, but apparently tree artifacts
         // sometimes store their own root directory in here. Sad.
         // https://github.com/bazelbuild/bazel/issues/9058
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java b/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java
index 03fed1a..9c7a570 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ActionInputMapHelper.java
@@ -157,10 +157,6 @@
       Map<Artifact, Collection<Artifact>> expandedArtifacts,
       ActionInputMapSink inputMap,
       Artifact depOwner) {
-    if (TreeArtifactValue.OMITTED_TREE_MARKER.equals(value)) {
-      inputMap.put(treeArtifact, FileArtifactValue.OMITTED_FILE_MARKER, depOwner);
-      return;
-    }
     ImmutableSet.Builder<Artifact> children = ImmutableSet.builder();
     for (Map.Entry<Artifact.TreeFileArtifact, FileArtifactValue> child :
         value.getChildValues().entrySet()) {
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandler.java b/src/main/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandler.java
index 475f63e..d3b4aad 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandler.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandler.java
@@ -512,19 +512,9 @@
 
   @Override
   public void markOmitted(Artifact output) {
-    Preconditions.checkState(
-        executionMode.get(), "Tried to mark %s omitted outside of execution", output);
-    boolean newlyOmitted = omittedOutputs.add(output);
-    if (output.isTreeArtifact()) {
-      // Tolerate marking a tree artifact as omitted multiple times so that callers don't have to
-      // deduplicate when a tree artifact has several omitted children.
-      if (newlyOmitted) {
-        store.putTreeArtifactData(output, TreeArtifactValue.OMITTED_TREE_MARKER);
-      }
-    } else {
-      Preconditions.checkState(newlyOmitted, "%s marked as omitted twice", output);
-      store.putArtifactData(output, FileArtifactValue.OMITTED_FILE_MARKER);
-    }
+    Preconditions.checkState(executionMode.get());
+    Preconditions.checkState(omittedOutputs.add(output), "%s marked as omitted twice", output);
+    store.putArtifactData(output, FileArtifactValue.OMITTED_FILE_MARKER);
   }
 
   @Override
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/ArtifactFunction.java b/src/main/java/com/google/devtools/build/lib/skyframe/ArtifactFunction.java
index d9f50b4..e2c4621 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/ArtifactFunction.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/ArtifactFunction.java
@@ -161,7 +161,7 @@
     }
   }
 
-  private static TreeArtifactValue createTreeArtifactValueFromActionKey(
+  private static SkyValue createTreeArtifactValueFromActionKey(
       ArtifactDependencies artifactDependencies, Environment env) throws InterruptedException {
     // Request the list of expanded actions from the ActionTemplate.
     ActionTemplateExpansion actionTemplateExpansion =
@@ -232,7 +232,7 @@
           children.isEmpty(),
           "Action template expansion has some but not all outputs omitted, present outputs: %s",
           children);
-      return TreeArtifactValue.OMITTED_TREE_MARKER;
+      return FileArtifactValue.OMITTED_FILE_MARKER;
     }
     return TreeArtifactValue.create(children);
   }
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/BUILD b/src/main/java/com/google/devtools/build/lib/skyframe/BUILD
index 098c34b..649cf3f 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/BUILD
@@ -2631,7 +2631,6 @@
     deps = [
         "//src/main/java/com/google/devtools/build/lib/actions",
         "//src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec",
-        "//src/main/java/com/google/devtools/build/lib/skyframe/serialization/autocodec:serialization-constant",
         "//src/main/java/com/google/devtools/build/lib/vfs",
         "//src/main/java/com/google/devtools/build/lib/vfs:pathfragment",
         "//src/main/java/com/google/devtools/build/skyframe:skyframe-objects",
diff --git a/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java b/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java
index 01920ca..7ac6c27 100644
--- a/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java
+++ b/src/main/java/com/google/devtools/build/lib/skyframe/TreeArtifactValue.java
@@ -26,7 +26,6 @@
 import com.google.devtools.build.lib.actions.HasDigest;
 import com.google.devtools.build.lib.actions.cache.DigestUtils;
 import com.google.devtools.build.lib.skyframe.serialization.autocodec.AutoCodec;
-import com.google.devtools.build.lib.skyframe.serialization.autocodec.SerializationConstant;
 import com.google.devtools.build.lib.vfs.Dirent;
 import com.google.devtools.build.lib.vfs.Dirent.Type;
 import com.google.devtools.build.lib.vfs.Path;
@@ -44,12 +43,14 @@
  * Value for TreeArtifacts, which contains a digest and the {@link FileArtifactValue}s of its child
  * {@link TreeFileArtifact}s.
  */
+@AutoCodec
 public class TreeArtifactValue implements HasDigest, SkyValue {
 
-  @SerializationConstant @AutoCodec.VisibleForSerialization
-  static final TreeArtifactValue EMPTY =
+  private static final TreeArtifactValue EMPTY =
       new TreeArtifactValue(
-          DigestUtils.fromMetadata(ImmutableMap.of()), ImmutableSortedMap.of(), /*remote=*/ false);
+          DigestUtils.fromMetadata(ImmutableMap.of()),
+          ImmutableSortedMap.of(),
+          /* remote= */ false);
 
   private final byte[] digest;
   private final ImmutableSortedMap<TreeFileArtifact, FileArtifactValue> childData;
@@ -160,67 +161,57 @@
   }
 
   /**
-   * Represents a tree artifact that was intentionally omitted, similar to {@link
-   * FileArtifactValue#OMITTED_FILE_MARKER}.
-   */
-  @SerializationConstant
-  public static final TreeArtifactValue OMITTED_TREE_MARKER = createMarker("OMITTED_TREE_MARKER");
-
-  /**
    * A TreeArtifactValue that represents a missing TreeArtifact. This is occasionally useful because
    * Java's concurrent collections disallow null members.
    */
-  static final TreeArtifactValue MISSING_TREE_ARTIFACT = createMarker("MISSING_TREE_ARTIFACT");
+  static final TreeArtifactValue MISSING_TREE_ARTIFACT =
+      new TreeArtifactValue(null, ImmutableSortedMap.of(), /* remote= */ false) {
+        @Override
+        FileArtifactValue getSelfData() {
+          throw new UnsupportedOperationException();
+        }
 
-  private static TreeArtifactValue createMarker(String toStringRepresentation) {
-    return new TreeArtifactValue(null, ImmutableSortedMap.of(), /*remote=*/ false) {
-      @Override
-      FileArtifactValue getSelfData() {
-        throw new UnsupportedOperationException(toString());
-      }
+        @Override
+        public ImmutableSet<TreeFileArtifact> getChildren() {
+          throw new UnsupportedOperationException();
+        }
 
-      @Override
-      public ImmutableSet<TreeFileArtifact> getChildren() {
-        throw new UnsupportedOperationException(toString());
-      }
+        @Override
+        ImmutableMap<TreeFileArtifact, FileArtifactValue> getChildValues() {
+          throw new UnsupportedOperationException();
+        }
 
-      @Override
-      ImmutableMap<TreeFileArtifact, FileArtifactValue> getChildValues() {
-        throw new UnsupportedOperationException(toString());
-      }
+        @Override
+        FileArtifactValue getMetadata() {
+          throw new UnsupportedOperationException();
+        }
 
-      @Override
-      FileArtifactValue getMetadata() {
-        throw new UnsupportedOperationException(toString());
-      }
+        @Override
+        ImmutableSet<PathFragment> getChildPaths() {
+          throw new UnsupportedOperationException();
+        }
 
-      @Override
-      ImmutableSet<PathFragment> getChildPaths() {
-        throw new UnsupportedOperationException(toString());
-      }
+        @Nullable
+        @Override
+        public byte[] getDigest() {
+          throw new UnsupportedOperationException();
+        }
 
-      @Nullable
-      @Override
-      public byte[] getDigest() {
-        throw new UnsupportedOperationException(toString());
-      }
+        @Override
+        public int hashCode() {
+          return 24; // my favorite number
+        }
 
-      @Override
-      public int hashCode() {
-        return System.identityHashCode(this);
-      }
+        @Override
+        public boolean equals(Object other) {
+          return this == other;
+        }
 
-      @Override
-      public boolean equals(Object other) {
-        return this == other;
-      }
-
-      @Override
-      public String toString() {
-        return toStringRepresentation;
-      }
-    };
-  }
+        @Override
+        public String toString() {
+          return "MISSING_TREE_ARTIFACT";
+        }
+      };
 
   private static void explodeDirectory(
       Path treeArtifactPath,
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java
index 4d9a7bc..db232b7 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ActionMetadataHandlerTest.java
@@ -18,7 +18,6 @@
 
 import com.google.common.collect.ImmutableList;
 import com.google.common.collect.ImmutableMap;
-import com.google.common.collect.ImmutableSet;
 import com.google.devtools.build.lib.actions.ActionInput;
 import com.google.devtools.build.lib.actions.ActionInputHelper;
 import com.google.devtools.build.lib.actions.ActionInputMap;
@@ -440,67 +439,6 @@
     assertThat(handler.getMetadata(ActionInputHelper.fromPath("/does/not/exist"))).isNull();
   }
 
-  @Test
-  public void omitRegularArtifact() {
-    OutputStore store = new MinimalOutputStore();
-    Artifact omitted =
-        ActionsTestUtil.createArtifactWithRootRelativePath(
-            outputRoot, PathFragment.create("omitted"));
-    Artifact consumed =
-        ActionsTestUtil.createArtifactWithRootRelativePath(
-            outputRoot, PathFragment.create("consumed"));
-    ActionMetadataHandler handler =
-        new ActionMetadataHandler(
-            new ActionInputMap(1),
-            /*expandedFilesets=*/ ImmutableMap.of(),
-            /*missingArtifactsAllowed=*/ false,
-            ImmutableSet.of(omitted, consumed),
-            /*tsgm=*/ null,
-            ArtifactPathResolver.IDENTITY,
-            store,
-            outputRoot.getRoot().asPath());
-
-    handler.discardOutputMetadata();
-    handler.markOmitted(omitted);
-
-    assertThat(handler.artifactOmitted(omitted)).isTrue();
-    assertThat(handler.artifactOmitted(consumed)).isFalse();
-    assertThat(store.getAllArtifactData())
-        .containsExactly(omitted, FileArtifactValue.OMITTED_FILE_MARKER);
-    assertThat(store.getAllTreeArtifactData()).isEmpty();
-  }
-
-  @Test
-  public void omitTreeArtifact() {
-    OutputStore store = new MinimalOutputStore();
-    SpecialArtifact omittedTree =
-        ActionsTestUtil.createTreeArtifactWithGeneratingAction(
-            outputRoot, PathFragment.create("omitted"));
-    SpecialArtifact consumedTree =
-        ActionsTestUtil.createTreeArtifactWithGeneratingAction(
-            outputRoot, PathFragment.create("consumed"));
-    ActionMetadataHandler handler =
-        new ActionMetadataHandler(
-            new ActionInputMap(1),
-            /*expandedFilesets=*/ ImmutableMap.of(),
-            /*missingArtifactsAllowed=*/ false,
-            ImmutableSet.of(omittedTree, consumedTree),
-            /*tsgm=*/ null,
-            ArtifactPathResolver.IDENTITY,
-            store,
-            outputRoot.getRoot().asPath());
-
-    handler.discardOutputMetadata();
-    handler.markOmitted(omittedTree);
-    handler.markOmitted(omittedTree); // Marking a tree artifact as omitted twice is tolerated.
-
-    assertThat(handler.artifactOmitted(omittedTree)).isTrue();
-    assertThat(handler.artifactOmitted(consumedTree)).isFalse();
-    assertThat(store.getAllTreeArtifactData())
-        .containsExactly(omittedTree, TreeArtifactValue.OMITTED_TREE_MARKER);
-    assertThat(store.getAllArtifactData()).isEmpty();
-  }
-
   private ImmutableMap<Artifact, ImmutableList<FilesetOutputSymlink>> createFilesetOutputSymlinkMap(
       HasDigest... digests) {
     int index = 1;
diff --git a/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java b/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java
index 5607782..8017fef 100644
--- a/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java
+++ b/src/test/java/com/google/devtools/build/lib/skyframe/ArtifactFunctionTest.java
@@ -278,7 +278,7 @@
     omittedOutputs.add(treeFileArtifact2);
 
     SkyValue value = evaluateArtifactValue(artifact2);
-    assertThat(value).isEqualTo(TreeArtifactValue.OMITTED_TREE_MARKER);
+    assertThat(value).isEqualTo(FileArtifactValue.OMITTED_FILE_MARKER);
   }
 
   @Test