diff --git a/src/main/java/com/google/devtools/build/lib/rules/proto/BUILD b/src/main/java/com/google/devtools/build/lib/rules/proto/BUILD
index 1067e484595629..6c45232c43407d 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/proto/BUILD
+++ b/src/main/java/com/google/devtools/build/lib/rules/proto/BUILD
@@ -51,6 +51,7 @@ java_library(
         "//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/common/options",
+        "//src/main/java/net/starlark/java/annot",
         "//src/main/java/net/starlark/java/eval",
         "//third_party:auto_value",
         "//third_party:guava",
diff --git a/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoConfiguration.java b/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoConfiguration.java
index e8d2b90cbeed78..722b6ab41b1692 100644
--- a/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoConfiguration.java
+++ b/src/main/java/com/google/devtools/build/lib/rules/proto/ProtoConfiguration.java
@@ -30,6 +30,7 @@
 import com.google.devtools.common.options.OptionEffectTag;
 import com.google.devtools.common.options.OptionMetadataTag;
 import java.util.List;
+import net.starlark.java.annot.StarlarkMethod;
 
 /** Configuration for Protocol Buffer Libraries. */
 @Immutable
@@ -201,6 +202,7 @@ public ProtoConfiguration(BuildOptions buildOptions) {
     this.options = options;
   }
 
+  @StarlarkMethod(name = "experimental_protoc_opts", structField = true, documented = false)
   public ImmutableList<String> protocOpts() {
     return protocOpts;
   }