diff --git a/BUILD b/BUILD
index 8786b5d7..c9d53165 100644
--- a/BUILD
+++ b/BUILD
@@ -96,6 +96,7 @@ proto_library(
         "//contrib/envoy/extensions/private_key_providers/cryptomb/v3alpha:pkg",
         "//contrib/envoy/extensions/private_key_providers/qat/v3alpha:pkg",
         "//contrib/envoy/extensions/regex_engines/hyperscan/v3alpha:pkg",
+        "//contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha:pkg",
         "//contrib/envoy/extensions/vcl/v3alpha:pkg",
         "//envoy/admin/v3:pkg",
         "//envoy/config/accesslog/v3:pkg",
diff --git a/contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha/BUILD b/contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha/BUILD
new file mode 100644
index 00000000..ec1e778e
--- /dev/null
+++ b/contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha/BUILD
@@ -0,0 +1,12 @@
+# DO NOT EDIT. This file is generated by tools/proto_format/proto_sync.py.
+
+load("@envoy_api//bazel:api_build_system.bzl", "api_proto_package")
+
+licenses(["notice"])  # Apache 2
+
+api_proto_package(
+    deps = [
+        "@com_github_cncf_udpa//udpa/annotations:pkg",
+        "@com_github_cncf_udpa//xds/annotations/v3:pkg",
+    ],
+)
diff --git a/contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha/golang.proto b/contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha/golang.proto
new file mode 100644
index 00000000..f22685af
--- /dev/null
+++ b/contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha/golang.proto
@@ -0,0 +1,51 @@
+syntax = "proto3";
+
+package envoy.extensions.router.cluster_specifier.golang.v3alpha;
+
+import "google/protobuf/any.proto";
+
+import "xds/annotations/v3/status.proto";
+
+import "udpa/annotations/status.proto";
+import "validate/validate.proto";
+
+option java_package = "io.envoyproxy.envoy.extensions.router.cluster_specifier.golang.v3alpha";
+option java_outer_classname = "GolangProto";
+option java_multiple_files = true;
+option go_package = "github.com/envoyproxy/go-control-plane/envoy/extensions/router/cluster_specifier/golang/v3alpha";
+option (udpa.annotations.file_status).package_version_status = ACTIVE;
+option (xds.annotations.v3.file_status).work_in_progress = true;
+
+// [#protodoc-title: Golang]
+//
+// For an overview of the Golang cluster specifier please see the :ref:`configuration reference documentation <config_http_cluster_specifier_golang>`.
+// [#extension: envoy.router.cluster_specifier_plugin.golang]
+
+// [#extension-category: envoy.router.cluster_specifier_plugin]
+message Config {
+  // Globally unique ID for a dynamic library file.
+  string library_id = 1 [(validate.rules).string = {min_len: 1}];
+
+  // Path to a dynamic library implementing the
+  // :repo:`ClusterSpecifier API <contrib/golang/router/cluster_specifier/source/go/pkg/api.ClusterSpecifier>`
+  // interface.
+  // [#comment:TODO(wangfakang): Support for downloading libraries from remote repositories.]
+  string library_path = 2 [(validate.rules).string = {min_len: 1}];
+
+  // Default cluster.
+  //
+  // It will be used when the specifier interface return empty string or panic.
+  //
+  string default_cluster = 3 [(validate.rules).string = {min_len: 1}];
+
+  // Configuration for the Go cluster specifier plugin.
+  //
+  // .. note::
+  //     This configuration is only parsed in the go cluster specifier, and is therefore not validated
+  //     by Envoy.
+  //
+  //     See the :repo:`StreamFilter API <contrib/golang/router/cluster_specifier/source/go/pkg/cluster_specifier/config.go>`
+  //     for more information about how the plugin's configuration data can be accessed.
+  //
+  google.protobuf.Any config = 4;
+}
diff --git a/versioning/BUILD b/versioning/BUILD
index 309506ce..651b30d2 100644
--- a/versioning/BUILD
+++ b/versioning/BUILD
@@ -34,6 +34,7 @@ proto_library(
         "//contrib/envoy/extensions/private_key_providers/cryptomb/v3alpha:pkg",
         "//contrib/envoy/extensions/private_key_providers/qat/v3alpha:pkg",
         "//contrib/envoy/extensions/regex_engines/hyperscan/v3alpha:pkg",
+        "//contrib/envoy/extensions/router/cluster_specifier/golang/v3alpha:pkg",
         "//contrib/envoy/extensions/vcl/v3alpha:pkg",
         "//envoy/admin/v3:pkg",
         "//envoy/config/accesslog/v3:pkg",