diff --git a/api/envoy/config/bootstrap/v2/bootstrap.proto b/api/envoy/config/bootstrap/v2/bootstrap.proto
index 58153bc94358..caa9dce53d67 100644
--- a/api/envoy/config/bootstrap/v2/bootstrap.proto
+++ b/api/envoy/config/bootstrap/v2/bootstrap.proto
@@ -264,6 +264,15 @@ message RuntimeLayer {
   message AdminLayer {
   }
 
+  // [#not-implemented-hide:]
+  message TdsLayer {
+    // Resource to subscribe to at *tds_config* for the TDS layer.
+    string name = 1;
+
+    // TDS configuration source.
+    envoy.api.v2.core.ConfigSource tds_config = 2;
+  }
+
   // Descriptive name for the runtime layer. This is only used for the runtime
   // :http:get:`/runtime` output.
   string name = 1;
@@ -274,6 +283,8 @@ message RuntimeLayer {
     google.protobuf.Struct static_layer = 2;
     DiskLayer disk_layer = 3;
     AdminLayer admin_layer = 4;
+    // [#not-implemented-hide:]
+    TdsLayer tds_layer = 5;
   }
 }
 
diff --git a/api/envoy/service/discovery/v2/BUILD b/api/envoy/service/discovery/v2/BUILD
index 33392fa67f86..fdd939758c4a 100644
--- a/api/envoy/service/discovery/v2/BUILD
+++ b/api/envoy/service/discovery/v2/BUILD
@@ -56,3 +56,20 @@ api_go_grpc_library(
         "//envoy/api/v2:discovery_go_proto",
     ],
 )
+
+api_proto_library_internal(
+    name = "tds",
+    srcs = ["tds.proto"],
+    has_services = 1,
+    deps = [
+        "//envoy/api/v2:discovery",
+    ],
+)
+
+api_go_grpc_library(
+    name = "tds",
+    proto = ":tds",
+    deps = [
+        "//envoy/api/v2:discovery_go_proto",
+    ],
+)
diff --git a/api/envoy/service/discovery/v2/tds.proto b/api/envoy/service/discovery/v2/tds.proto
new file mode 100644
index 000000000000..d0280f5fd3c3
--- /dev/null
+++ b/api/envoy/service/discovery/v2/tds.proto
@@ -0,0 +1,34 @@
+syntax = "proto3";
+
+package envoy.service.discovery.v2;
+
+option java_outer_classname = "TdsProto";
+option java_multiple_files = true;
+option java_package = "io.envoyproxy.envoy.service.discovery.v2";
+option java_generic_services = true;
+
+import "envoy/api/v2/discovery.proto";
+
+import "google/api/annotations.proto";
+import "google/protobuf/struct.proto";
+
+// Discovery service for Runtime resources.
+// [#not-implemented-hide:]
+service RuntimeDiscoveryService {
+  rpc StreamRuntime(stream envoy.api.v2.DiscoveryRequest)
+      returns (stream envoy.api.v2.DiscoveryResponse) {
+  }
+
+  rpc FetchRuntime(envoy.api.v2.DiscoveryRequest) returns (envoy.api.v2.DiscoveryResponse) {
+    option (google.api.http) = {
+      post: "/v2/discovery:runtime"
+      body: "*"
+    };
+  }
+}
+
+// TDS resource type. This describes a layer in the runtime virtual filesystem.
+// [#not-implemented-hide:]
+message Runtime {
+  google.protobuf.Struct layer = 1;
+}
diff --git a/api/test/build/BUILD b/api/test/build/BUILD
index 3260fd418147..9eb525246458 100644
--- a/api/test/build/BUILD
+++ b/api/test/build/BUILD
@@ -13,6 +13,7 @@ api_cc_test(
         "//envoy/service/accesslog/v2:als",
         "//envoy/service/discovery/v2:ads",
         "//envoy/service/discovery/v2:hds",
+        "//envoy/service/discovery/v2:tds",
         "//envoy/service/metrics/v2:metrics_service",
         "//envoy/service/ratelimit/v2:rls",
     ],
diff --git a/api/test/build/build_test.cc b/api/test/build/build_test.cc
index 6397c6391ec8..f0a8e7bf432c 100644
--- a/api/test/build/build_test.cc
+++ b/api/test/build/build_test.cc
@@ -18,6 +18,8 @@ int main(int argc, char* argv[]) {
       "envoy.service.discovery.v2.AggregatedDiscoveryService.StreamAggregatedResources",
       "envoy.service.discovery.v2.HealthDiscoveryService.FetchHealthCheck",
       "envoy.service.discovery.v2.HealthDiscoveryService.StreamHealthCheck",
+      "envoy.service.discovery.v2.RuntimeDiscoveryService.FetchRuntime",
+      "envoy.service.discovery.v2.RuntimeDiscoveryService.StreamRuntime",
       "envoy.service.accesslog.v2.AccessLogService.StreamAccessLogs",
       "envoy.service.metrics.v2.MetricsService.StreamMetrics",
       "envoy.service.ratelimit.v2.RateLimitService.ShouldRateLimit",
diff --git a/source/server/BUILD b/source/server/BUILD
index 86e97f8231cb..8ae94030aa92 100644
--- a/source/server/BUILD
+++ b/source/server/BUILD
@@ -300,6 +300,7 @@ envoy_cc_library(
         "@envoy_api//envoy/api/v2:rds_cc",
         "@envoy_api//envoy/service/discovery/v2:ads_cc",
         "@envoy_api//envoy/service/discovery/v2:hds_cc",
+        "@envoy_api//envoy/service/discovery/v2:tds_cc",
         "@envoy_api//envoy/service/ratelimit/v2:rls_cc",
     ],
 )
diff --git a/source/server/proto_descriptors.cc b/source/server/proto_descriptors.cc
index 68019c209f7e..b77cca909414 100644
--- a/source/server/proto_descriptors.cc
+++ b/source/server/proto_descriptors.cc
@@ -29,6 +29,8 @@ void validateProtoDescriptors() {
       "envoy.service.discovery.v2.AggregatedDiscoveryService.StreamAggregatedResources",
       "envoy.service.discovery.v2.HealthDiscoveryService.FetchHealthCheck",
       "envoy.service.discovery.v2.HealthDiscoveryService.StreamHealthCheck",
+      "envoy.service.discovery.v2.RuntimeDiscoveryService.FetchRuntime",
+      "envoy.service.discovery.v2.RuntimeDiscoveryService.StreamRuntime",
       "envoy.service.ratelimit.v2.RateLimitService.ShouldRateLimit",
   };