diff --git a/generator/integration_tests/golden/v1/internal/request_id_connection_impl.cc b/generator/integration_tests/golden/v1/internal/request_id_connection_impl.cc
index 56869279ce201..ef9c362d669cc 100644
--- a/generator/integration_tests/golden/v1/internal/request_id_connection_impl.cc
+++ b/generator/integration_tests/golden/v1/internal/request_id_connection_impl.cc
@@ -66,20 +66,27 @@ RequestIdServiceConnectionImpl::RequestIdServiceConnectionImpl(
 StatusOr<google::test::requestid::v1::Foo>
 RequestIdServiceConnectionImpl::CreateFoo(google::test::requestid::v1::CreateFooRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
+  auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   return google::cloud::internal::RetryLoop(
       retry_policy(*current), backoff_policy(*current),
-      idempotency_policy(*current)->CreateFoo(request),
+      idempotency_policy(*current)->CreateFoo(request_copy),
       [this](grpc::ClientContext& context,
              google::test::requestid::v1::CreateFooRequest const& request) {
         return stub_->CreateFoo(context, request);
       },
-      request, __func__);
+      request_copy, __func__);
 }
 
 future<StatusOr<google::test::requestid::v1::Foo>>
 RequestIdServiceConnectionImpl::RenameFoo(google::test::requestid::v1::RenameFooRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
   auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   auto const idempotent =
       idempotency_policy(*current)->RenameFoo(request_copy);
   return google::cloud::internal::AsyncLongRunningOperation<google::test::requestid::v1::Foo>(
@@ -138,6 +145,9 @@ future<StatusOr<google::test::requestid::v1::Foo>>
 RequestIdServiceConnectionImpl::AsyncCreateFoo(google::test::requestid::v1::CreateFooRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
   auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   auto const idempotent =
       idempotency_policy(*current)->CreateFoo(request_copy);
   return google::cloud::internal::AsyncRetryLoop(
diff --git a/generator/integration_tests/golden/v1/internal/request_id_connection_impl.h b/generator/integration_tests/golden/v1/internal/request_id_connection_impl.h
index 3f1e965feeb9f..44b0f333da6b5 100644
--- a/generator/integration_tests/golden/v1/internal/request_id_connection_impl.h
+++ b/generator/integration_tests/golden/v1/internal/request_id_connection_impl.h
@@ -27,6 +27,7 @@
 #include "google/cloud/background_threads.h"
 #include "google/cloud/backoff_policy.h"
 #include "google/cloud/future.h"
+#include "google/cloud/internal/invocation_id_generator.h"
 #include "google/cloud/options.h"
 #include "google/cloud/polling_policy.h"
 #include "google/cloud/status_or.h"
@@ -68,6 +69,9 @@ class RequestIdServiceConnectionImpl
   std::unique_ptr<google::cloud::BackgroundThreads> background_;
   std::shared_ptr<golden_v1_internal::RequestIdServiceStub> stub_;
   Options options_;
+  std::shared_ptr<google::cloud::internal::InvocationIdGenerator>
+      invocation_id_generator_ =
+          std::make_shared<google::cloud::internal::InvocationIdGenerator>();
 };
 
 GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_END
diff --git a/generator/integration_tests/golden/v1/request_id_client.h b/generator/integration_tests/golden/v1/request_id_client.h
index e5c3e31526b71..17674f9e848a1 100644
--- a/generator/integration_tests/golden/v1/request_id_client.h
+++ b/generator/integration_tests/golden/v1/request_id_client.h
@@ -101,8 +101,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L80}
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
+  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L79}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
   ///
   // clang-format on
   StatusOr<google::test::requestid::v1::Foo>
@@ -131,8 +131,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L80}
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
+  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L79}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
   ///
   // clang-format on
   StatusOr<google::test::requestid::v1::Foo>
@@ -165,8 +165,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
-  /// [google.test.requestid.v1.RenameFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L100}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
+  /// [google.test.requestid.v1.RenameFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L99}
   ///
   // clang-format on
   future<StatusOr<google::test::requestid::v1::Foo>>
@@ -202,8 +202,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
-  /// [google.test.requestid.v1.RenameFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L100}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
+  /// [google.test.requestid.v1.RenameFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L99}
   ///
   // clang-format on
   future<StatusOr<google::test::requestid::v1::Foo>>
@@ -236,8 +236,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
-  /// [google.test.requestid.v1.ListFoosRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L135}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
+  /// [google.test.requestid.v1.ListFoosRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L134}
   ///
   // clang-format on
   StreamRange<google::test::requestid::v1::Foo>
@@ -275,8 +275,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
-  /// [google.test.requestid.v1.ListFoosRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L135}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
+  /// [google.test.requestid.v1.ListFoosRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L134}
   ///
   // clang-format on
   StreamRange<google::test::requestid::v1::Foo>
@@ -301,8 +301,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L80}
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
+  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L79}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
   ///
   // clang-format on
   future<StatusOr<google::test::requestid::v1::Foo>>
@@ -331,8 +331,8 @@ class RequestIdServiceClient {
   /// [`future`]: @ref google::cloud::future
   /// [`StatusOr`]: @ref google::cloud::StatusOr
   /// [`Status`]: @ref google::cloud::Status
-  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L80}
-  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L66}
+  /// [google.test.requestid.v1.CreateFooRequest]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L79}
+  /// [google.test.requestid.v1.Foo]: @googleapis_reference_link{generator/integration_tests/test_request_id.proto#L65}
   ///
   // clang-format on
   future<StatusOr<google::test::requestid::v1::Foo>>
diff --git a/generator/integration_tests/golden/v1/request_id_connection_idempotency_policy.cc b/generator/integration_tests/golden/v1/request_id_connection_idempotency_policy.cc
index 9412d9297941a..5236ebcb3f724 100644
--- a/generator/integration_tests/golden/v1/request_id_connection_idempotency_policy.cc
+++ b/generator/integration_tests/golden/v1/request_id_connection_idempotency_policy.cc
@@ -33,11 +33,13 @@ RequestIdServiceConnectionIdempotencyPolicy::clone() const {
   return std::make_unique<RequestIdServiceConnectionIdempotencyPolicy>(*this);
 }
 
-Idempotency RequestIdServiceConnectionIdempotencyPolicy::CreateFoo(google::test::requestid::v1::CreateFooRequest const&) {
+Idempotency RequestIdServiceConnectionIdempotencyPolicy::CreateFoo(google::test::requestid::v1::CreateFooRequest const& request) {
+  if (!request.request_id().empty()) return Idempotency::kIdempotent;
   return Idempotency::kNonIdempotent;
 }
 
-Idempotency RequestIdServiceConnectionIdempotencyPolicy::RenameFoo(google::test::requestid::v1::RenameFooRequest const&) {
+Idempotency RequestIdServiceConnectionIdempotencyPolicy::RenameFoo(google::test::requestid::v1::RenameFooRequest const& request) {
+  if (!request.request_id().empty()) return Idempotency::kIdempotent;
   return Idempotency::kNonIdempotent;
 }
 
diff --git a/generator/integration_tests/test_request_id.proto b/generator/integration_tests/test_request_id.proto
index 8c229df6d4da2..004993b96a209 100644
--- a/generator/integration_tests/test_request_id.proto
+++ b/generator/integration_tests/test_request_id.proto
@@ -16,7 +16,6 @@ syntax = "proto3";
 
 package google.test.requestid.v1;
 
-import "google/api/annotations.proto";
 import "google/api/client.proto";
 import "google/api/field_behavior.proto";
 import "google/api/field_info.proto";
diff --git a/generator/integration_tests/tests/request_id_connection_impl_test.cc b/generator/integration_tests/tests/request_id_connection_impl_test.cc
index e81a1b0148bc8..f751e98e041ad 100644
--- a/generator/integration_tests/tests/request_id_connection_impl_test.cc
+++ b/generator/integration_tests/tests/request_id_connection_impl_test.cc
@@ -20,7 +20,6 @@
 #include "google/cloud/testing_util/status_matchers.h"
 #include <gmock/gmock.h>
 #include <memory>
-#include <set>
 #include <string>
 #include <utility>
 
@@ -97,10 +96,20 @@ auto WithRequestId(std::string expected) {
 template <typename Request>
 auto WithoutRequestId() {
   return ResultOf(
-      "request does not have request_id",
+      "request has empty request_id",
       [](Request const& request) { return request.request_id(); }, IsEmpty());
 }
 
+template <typename Request>
+auto RequestIdIsUuidV4() {
+  using ::testing::ContainsRegex;
+  return ResultOf(
+      "request has request_id in UUIDV4 format",
+      [](Request const& request) { return request.request_id(); },
+      ContainsRegex(
+          "[0-9a-f]{8}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{4}-[0-9a-f]{12}"));
+}
+
 auto MakeTestConnection(
     std::shared_ptr<golden_v1_internal::RequestIdServiceStub> stub) {
   auto options = golden_v1_internal::RequestIdServiceDefaultOptions({});
@@ -109,9 +118,14 @@ auto MakeTestConnection(
       std::move(background), std::move(stub), std::move(options));
 }
 
+Status TransientError() {
+  return Status(StatusCode::kUnavailable, "try-again");
+}
+
 TEST(RequestIdTest, UnaryRpc) {
   auto mock = std::make_shared<MockRequestIdServiceStub>();
-  EXPECT_CALL(*mock, CreateFoo(_, WithoutRequestId<CreateFooRequest>()))
+  EXPECT_CALL(*mock, CreateFoo(_, RequestIdIsUuidV4<CreateFooRequest>()))
+      .WillOnce(Return(TransientError()))
       .WillOnce(Return(Foo{}));
 
   auto connection = MakeTestConnection(mock);
@@ -125,6 +139,7 @@ TEST(RequestIdTest, UnaryRpcExplicit) {
   auto mock = std::make_shared<MockRequestIdServiceStub>();
   EXPECT_CALL(*mock,
               CreateFoo(_, WithRequestId<CreateFooRequest>("test-request-id")))
+      .WillOnce(Return(TransientError()))
       .WillOnce(Return(Foo{}));
 
   auto connection = MakeTestConnection(mock);
@@ -137,7 +152,10 @@ TEST(RequestIdTest, UnaryRpcExplicit) {
 
 TEST(RequestIdTest, AsyncUnaryRpc) {
   auto mock = std::make_shared<MockRequestIdServiceStub>();
-  EXPECT_CALL(*mock, AsyncCreateFoo(_, _, WithoutRequestId<CreateFooRequest>()))
+  EXPECT_CALL(*mock,
+              AsyncCreateFoo(_, _, RequestIdIsUuidV4<CreateFooRequest>()))
+      .WillOnce(
+          Return(ByMove(make_ready_future(StatusOr<Foo>(TransientError())))))
       .WillOnce(Return(ByMove(make_ready_future(make_status_or(Foo{})))));
 
   auto connection = MakeTestConnection(mock);
@@ -152,6 +170,8 @@ TEST(RequestIdTest, AsyncUnaryRpcExplicit) {
   EXPECT_CALL(
       *mock,
       AsyncCreateFoo(_, _, WithRequestId<CreateFooRequest>("test-request-id")))
+      .WillOnce(
+          Return(ByMove(make_ready_future(StatusOr<Foo>(TransientError())))))
       .WillOnce(Return(ByMove(make_ready_future(make_status_or(Foo{})))));
 
   auto connection = MakeTestConnection(mock);
@@ -165,7 +185,9 @@ TEST(RequestIdTest, AsyncUnaryRpcExplicit) {
 TEST(RequestIdTest, Lro) {
   auto mock = std::make_shared<MockRequestIdServiceStub>();
   EXPECT_CALL(*mock,
-              AsyncRenameFoo(_, _, _, WithoutRequestId<RenameFooRequest>()))
+              AsyncRenameFoo(_, _, _, RequestIdIsUuidV4<RenameFooRequest>()))
+      .WillOnce(Return(ByMove(make_ready_future(
+          StatusOr<google::longrunning::Operation>(TransientError())))))
       .WillOnce(Return(ByMove(make_ready_future(
           make_status_or(google::longrunning::Operation{})))));
   EXPECT_CALL(*mock, AsyncGetOperation).WillOnce([] {
@@ -187,6 +209,8 @@ TEST(RequestIdTest, LroExplicit) {
   EXPECT_CALL(
       *mock, AsyncRenameFoo(_, _, _,
                             WithRequestId<RenameFooRequest>("test-request-id")))
+      .WillOnce(Return(ByMove(make_ready_future(
+          StatusOr<google::longrunning::Operation>(TransientError())))))
       .WillOnce(Return(ByMove(make_ready_future(
           make_status_or(google::longrunning::Operation{})))));
   EXPECT_CALL(*mock, AsyncGetOperation).WillOnce([] {
@@ -206,17 +230,17 @@ TEST(RequestIdTest, LroExplicit) {
 
 TEST(RequestIdTest, Pagination) {
   auto mock = std::make_shared<MockRequestIdServiceStub>();
-  std::set<std::string> sequence_ids;
+  std::vector<std::string> sequence_ids;
   EXPECT_CALL(*mock, ListFoos(_, WithoutRequestId<ListFoosRequest>()))
       .WillOnce([&](auto&, auto const& request) {
-        sequence_ids.insert(request.request_id());
+        sequence_ids.push_back(request.request_id());
         ListFoosResponse response;
         response.add_foos()->set_name("name-0");
         response.set_next_page_token("test-token-0");
         return response;
       })
       .WillOnce([&](auto&, auto const& request) {
-        sequence_ids.insert(request.request_id());
+        sequence_ids.push_back(request.request_id());
         ListFoosResponse response;
         response.add_foos()->set_name("name-1");
         return response;
@@ -234,26 +258,23 @@ TEST(RequestIdTest, Pagination) {
   };
   EXPECT_THAT(results, ElementsAre(IsOkAndHolds(with_name("name-0")),
                                    IsOkAndHolds(with_name("name-1"))));
-  EXPECT_THAT(sequence_ids, ElementsAre(IsEmpty()));
+  EXPECT_THAT(sequence_ids, ElementsAre(IsEmpty(), IsEmpty()));
 }
 
 TEST(RequestIdTest, PaginationExplicit) {
   auto mock = std::make_shared<MockRequestIdServiceStub>();
-  std::set<std::string> sequence_ids;
-  ::testing::InSequence sequence;
+  std::vector<std::string> sequence_ids;
   EXPECT_CALL(*mock,
               ListFoos(_, WithRequestId<ListFoosRequest>("test-request-id")))
       .WillOnce([&](auto&, auto const& request) {
-        sequence_ids.insert(request.request_id());
+        sequence_ids.push_back(request.request_id());
         ListFoosResponse response;
         response.add_foos()->set_name("name-0");
         response.set_next_page_token("test-token-0");
         return response;
-      });
-  EXPECT_CALL(*mock,
-              ListFoos(_, WithRequestId<ListFoosRequest>("test-request-id")))
+      })
       .WillOnce([&](auto&, auto const& request) {
-        sequence_ids.insert(request.request_id());
+        sequence_ids.push_back(request.request_id());
         ListFoosResponse response;
         response.add_foos()->set_name("name-1");
         return response;
@@ -272,7 +293,7 @@ TEST(RequestIdTest, PaginationExplicit) {
   };
   EXPECT_THAT(results, ElementsAre(IsOkAndHolds(with_name("name-0")),
                                    IsOkAndHolds(with_name("name-1"))));
-  EXPECT_THAT(sequence_ids, ElementsAre("test-request-id"));
+  EXPECT_THAT(sequence_ids, ElementsAre("test-request-id", "test-request-id"));
 }
 
 }  // namespace
diff --git a/generator/integration_tests/tests/request_id_idempotency_test.cc b/generator/integration_tests/tests/request_id_idempotency_test.cc
index fc596e2429791..d3d35e51fa6a0 100644
--- a/generator/integration_tests/tests/request_id_idempotency_test.cc
+++ b/generator/integration_tests/tests/request_id_idempotency_test.cc
@@ -30,18 +30,24 @@ TEST(RequestIdIdempotency, CreateFoo) {
   auto policy = MakeDefaultRequestIdServiceConnectionIdempotencyPolicy();
   CreateFooRequest request;
   EXPECT_EQ(policy->CreateFoo(request), Idempotency::kNonIdempotent);
+  request.set_request_id("test-request-id");
+  EXPECT_EQ(policy->CreateFoo(request), Idempotency::kIdempotent);
 }
 
 TEST(RequestIdIdempotency, ListFoos) {
   auto policy = MakeDefaultRequestIdServiceConnectionIdempotencyPolicy();
   ListFoosRequest request;
   EXPECT_EQ(policy->ListFoos(request), Idempotency::kNonIdempotent);
+  request.set_request_id("test-request-id");
+  EXPECT_EQ(policy->ListFoos(request), Idempotency::kNonIdempotent);
 }
 
 TEST(RequestIdIdempotency, RenameFoo) {
   auto policy = MakeDefaultRequestIdServiceConnectionIdempotencyPolicy();
   RenameFooRequest request;
   EXPECT_EQ(policy->RenameFoo(request), Idempotency::kNonIdempotent);
+  request.set_request_id("test-request-id");
+  EXPECT_EQ(policy->RenameFoo(request), Idempotency::kIdempotent);
 }
 
 }  // namespace
diff --git a/generator/internal/connection_impl_generator.cc b/generator/internal/connection_impl_generator.cc
index da3b176f33d0c..3d733dcbfa68a 100644
--- a/generator/internal/connection_impl_generator.cc
+++ b/generator/internal/connection_impl_generator.cc
@@ -57,6 +57,7 @@ Status ConnectionImplGenerator::GenerateHeader() {
            : "",
        "google/cloud/background_threads.h", "google/cloud/backoff_policy.h",
        HasLongrunningMethod() ? "google/cloud/future.h" : "",
+       HasRequestId() ? "google/cloud/internal/invocation_id_generator.h" : "",
        "google/cloud/options.h",
        HasLongrunningMethod() ? "google/cloud/polling_policy.h" : "",
        "google/cloud/status_or.h",
@@ -117,11 +118,17 @@ class $connection_class_name$Impl
  private:
   std::unique_ptr<google::cloud::BackgroundThreads> background_;
   std::shared_ptr<$product_internal_namespace$::$stub_class_name$> stub_;
-  Options options_;
-)""");
+  Options options_;)""");
+
+  if (HasRequestId()) {
+    HeaderPrint(R"""(
+  std::shared_ptr<google::cloud::internal::InvocationIdGenerator>
+      invocation_id_generator_ =
+          std::make_shared<google::cloud::internal::InvocationIdGenerator>();)""");
+  }
 
   // This closes the *ConnectionImpl class definition.
-  HeaderPrint("};\n");
+  HeaderPrint("\n};\n");
 
   HeaderCloseNamespaces();
 
@@ -324,6 +331,9 @@ StreamRange<$response_type$>
     return {};
   }
 
+  // We do not need to consider `HasRequestId()` in paginated APIs. The main
+  // motivation for `HasRequestId()` is to make the request idempotent, but
+  // paginated APIs are always read-only and therefore idempotent.
   if (IsPaginated(method)) {
     return R"""(
 StreamRange<$range_output_type$>
@@ -363,6 +373,12 @@ StreamRange<$range_output_type$>
             ? R"""(future<Status>)"""
             : R"""(future<StatusOr<$longrunning_deduced_response_type$>>)""";
 
+    auto const* request_id_fragment = HasRequestId(method) ? R"""(
+  if (request_copy.$request_id_field_name$().empty()) {
+    request_copy.set_$request_id_field_name$(invocation_id_generator_->MakeInvocationId());
+  })"""
+                                                           : "";
+
     // One of the variations is how to extract the value from the operation
     // result, some operations use the metadata, some the data. We need to
     // provide the right function to internal::AsyncLongRunningOperation.
@@ -387,7 +403,8 @@ StreamRange<$range_output_type$>
                         R"""(
 $connection_class_name$Impl::$method_name$($request_type$ const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
-  auto request_copy = request;
+  auto request_copy = request;)""",
+                        request_id_fragment, R"""(
   auto const idempotent =
       idempotency_policy(*current)->$method_name$(request_copy);
   return google::cloud::internal::AsyncLongRunningOperation<$longrunning_deduced_response_type$>(
@@ -424,6 +441,26 @@ StreamRange<$range_output_type$>
   auto const* return_fragment = IsResponseTypeEmpty(method)
                                     ? R"""(Status)"""
                                     : R"""(StatusOr<$response_type$>)""";
+  if (HasRequestId(method)) {
+    return absl::StrCat("\n", return_fragment, R"""(
+$connection_class_name$Impl::$method_name$($request_type$ const& request) {
+  auto current = google::cloud::internal::SaveCurrentOptions();
+  auto request_copy = request;
+  if (request_copy.$request_id_field_name$().empty()) {
+    request_copy.set_$request_id_field_name$(invocation_id_generator_->MakeInvocationId());
+  }
+  return google::cloud::internal::RetryLoop(
+      retry_policy(*current), backoff_policy(*current),
+      idempotency_policy(*current)->$method_name$(request_copy),
+      [this](grpc::ClientContext& context,
+             $request_type$ const& request) {
+        return stub_->$method_name$(context, request);
+      },
+      request_copy, __func__);
+}
+)""");
+  }
+
   return absl::StrCat("\n", return_fragment,
                       R"""(
 $connection_class_name$Impl::$method_name$($request_type$ const& request) {
@@ -445,12 +482,19 @@ std::string ConnectionImplGenerator::AsyncMethodDefinition(
   auto const* return_fragment =
       IsResponseTypeEmpty(method) ? R"""(future<Status>)"""
                                   : R"""(future<StatusOr<$response_type$>>)""";
+  auto const* request_id_fragment = HasRequestId(method) ?
+                                                         R"""(
+  if (request_copy.$request_id_field_name$().empty()) {
+    request_copy.set_$request_id_field_name$(invocation_id_generator_->MakeInvocationId());
+  })"""
+                                                         : "";
 
   return absl::StrCat("\n", return_fragment,
                       R"""(
 $connection_class_name$Impl::Async$method_name$($request_type$ const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
-  auto request_copy = request;
+  auto request_copy = request;)""",
+                      request_id_fragment, R"""(
   auto const idempotent =
       idempotency_policy(*current)->$method_name$(request_copy);
   return google::cloud::internal::AsyncRetryLoop(
diff --git a/generator/internal/connection_impl_generator.h b/generator/internal/connection_impl_generator.h
index 5e07d459b0df1..0656f586b96a0 100644
--- a/generator/internal/connection_impl_generator.h
+++ b/generator/internal/connection_impl_generator.h
@@ -50,9 +50,9 @@ class ConnectionImplGenerator : public ServiceCodeGenerator {
       google::protobuf::MethodDescriptor const& method);
   static std::string AsyncMethodDeclaration(
       google::protobuf::MethodDescriptor const& method);
-  static std::string MethodDefinition(
+  std::string MethodDefinition(
       google::protobuf::MethodDescriptor const& method);
-  static std::string AsyncMethodDefinition(
+  std::string AsyncMethodDefinition(
       google::protobuf::MethodDescriptor const& method);
 };
 
diff --git a/generator/internal/idempotency_policy_generator.cc b/generator/internal/idempotency_policy_generator.cc
index cecdf981ea460..164ba78816b87 100644
--- a/generator/internal/idempotency_policy_generator.cc
+++ b/generator/internal/idempotency_policy_generator.cc
@@ -18,6 +18,7 @@
 #include "generator/internal/pagination.h"
 #include "generator/internal/predicate_utils.h"
 #include "generator/internal/printer.h"
+#include "generator/internal/request_id.h"
 #include "google/cloud/internal/absl_str_cat_quiet.h"
 #include <google/protobuf/descriptor.h>
 
@@ -165,10 +166,29 @@ Idempotency $idempotency_class_name$::$method_name$(
 
     // TODO(#9982) - we should pass `$request_type$ const&` here
     if (IsPaginated(method)) {
-      CcPrintMethod(method, __FILE__, __LINE__, R"""(
+      if (HasRequestId(method)) {
+        CcPrintMethod(method, __FILE__, __LINE__, R"""(
+Idempotency $idempotency_class_name$::$method_name$($request_type$ request) { // NOLINT
+  if (!request.$request_id_field_name$().empty()) return Idempotency::kIdempotent;
+  return Idempotency::$idempotency$;
+}
+)""");
+      } else {
+        CcPrintMethod(method, __FILE__, __LINE__, R"""(
 Idempotency $idempotency_class_name$::$method_name$($request_type$) {  // NOLINT
   return Idempotency::$idempotency$;
 }
+)""");
+      }
+      continue;
+    }
+
+    if (HasRequestId(method)) {
+      CcPrintMethod(method, __FILE__, __LINE__, R"""(
+Idempotency $idempotency_class_name$::$method_name$($request_type$ const& request) {
+  if (!request.$request_id_field_name$().empty()) return Idempotency::kIdempotent;
+  return Idempotency::$idempotency$;
+}
 )""");
       continue;
     }
diff --git a/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.cc b/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.cc
index ccf10401f75b3..32b8c49abf091 100644
--- a/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.cc
+++ b/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.cc
@@ -70,41 +70,53 @@ StatusOr<google::storage::control::v2::Folder>
 StorageControlConnectionImpl::CreateFolder(
     google::storage::control::v2::CreateFolderRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
+  auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   return google::cloud::internal::RetryLoop(
       retry_policy(*current), backoff_policy(*current),
-      idempotency_policy(*current)->CreateFolder(request),
+      idempotency_policy(*current)->CreateFolder(request_copy),
       [this](grpc::ClientContext& context,
              google::storage::control::v2::CreateFolderRequest const& request) {
         return stub_->CreateFolder(context, request);
       },
-      request, __func__);
+      request_copy, __func__);
 }
 
 Status StorageControlConnectionImpl::DeleteFolder(
     google::storage::control::v2::DeleteFolderRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
+  auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   return google::cloud::internal::RetryLoop(
       retry_policy(*current), backoff_policy(*current),
-      idempotency_policy(*current)->DeleteFolder(request),
+      idempotency_policy(*current)->DeleteFolder(request_copy),
       [this](grpc::ClientContext& context,
              google::storage::control::v2::DeleteFolderRequest const& request) {
         return stub_->DeleteFolder(context, request);
       },
-      request, __func__);
+      request_copy, __func__);
 }
 
 StatusOr<google::storage::control::v2::Folder>
 StorageControlConnectionImpl::GetFolder(
     google::storage::control::v2::GetFolderRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
+  auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   return google::cloud::internal::RetryLoop(
       retry_policy(*current), backoff_policy(*current),
-      idempotency_policy(*current)->GetFolder(request),
+      idempotency_policy(*current)->GetFolder(request_copy),
       [this](grpc::ClientContext& context,
              google::storage::control::v2::GetFolderRequest const& request) {
         return stub_->GetFolder(context, request);
       },
-      request, __func__);
+      request_copy, __func__);
 }
 
 StreamRange<google::storage::control::v2::Folder>
@@ -143,6 +155,9 @@ StorageControlConnectionImpl::RenameFolder(
     google::storage::control::v2::RenameFolderRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
   auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   auto const idempotent =
       idempotency_policy(*current)->RenameFolder(request_copy);
   return google::cloud::internal::AsyncLongRunningOperation<
@@ -179,13 +194,17 @@ StatusOr<google::storage::control::v2::StorageLayout>
 StorageControlConnectionImpl::GetStorageLayout(
     google::storage::control::v2::GetStorageLayoutRequest const& request) {
   auto current = google::cloud::internal::SaveCurrentOptions();
+  auto request_copy = request;
+  if (request_copy.request_id().empty()) {
+    request_copy.set_request_id(invocation_id_generator_->MakeInvocationId());
+  }
   return google::cloud::internal::RetryLoop(
       retry_policy(*current), backoff_policy(*current),
-      idempotency_policy(*current)->GetStorageLayout(request),
+      idempotency_policy(*current)->GetStorageLayout(request_copy),
       [this](grpc::ClientContext& context,
              google::storage::control::v2::GetStorageLayoutRequest const&
                  request) { return stub_->GetStorageLayout(context, request); },
-      request, __func__);
+      request_copy, __func__);
 }
 
 GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_END
diff --git a/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.h b/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.h
index 17da06b9b3b03..3f7904570ca3f 100644
--- a/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.h
+++ b/google/cloud/storagecontrol/v2/internal/storage_control_connection_impl.h
@@ -27,6 +27,7 @@
 #include "google/cloud/background_threads.h"
 #include "google/cloud/backoff_policy.h"
 #include "google/cloud/future.h"
+#include "google/cloud/internal/invocation_id_generator.h"
 #include "google/cloud/options.h"
 #include "google/cloud/polling_policy.h"
 #include "google/cloud/status_or.h"
@@ -77,6 +78,9 @@ class StorageControlConnectionImpl
   std::unique_ptr<google::cloud::BackgroundThreads> background_;
   std::shared_ptr<storagecontrol_v2_internal::StorageControlStub> stub_;
   Options options_;
+  std::shared_ptr<google::cloud::internal::InvocationIdGenerator>
+      invocation_id_generator_ =
+          std::make_shared<google::cloud::internal::InvocationIdGenerator>();
 };
 
 GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_END
diff --git a/google/cloud/storagecontrol/v2/storage_control_connection_idempotency_policy.cc b/google/cloud/storagecontrol/v2/storage_control_connection_idempotency_policy.cc
index 21784a4d88f4f..20f6e0a33d3ba 100644
--- a/google/cloud/storagecontrol/v2/storage_control_connection_idempotency_policy.cc
+++ b/google/cloud/storagecontrol/v2/storage_control_connection_idempotency_policy.cc
@@ -35,17 +35,20 @@ StorageControlConnectionIdempotencyPolicy::clone() const {
 }
 
 Idempotency StorageControlConnectionIdempotencyPolicy::CreateFolder(
-    google::storage::control::v2::CreateFolderRequest const&) {
+    google::storage::control::v2::CreateFolderRequest const& request) {
+  if (!request.request_id().empty()) return Idempotency::kIdempotent;
   return Idempotency::kNonIdempotent;
 }
 
 Idempotency StorageControlConnectionIdempotencyPolicy::DeleteFolder(
-    google::storage::control::v2::DeleteFolderRequest const&) {
+    google::storage::control::v2::DeleteFolderRequest const& request) {
+  if (!request.request_id().empty()) return Idempotency::kIdempotent;
   return Idempotency::kNonIdempotent;
 }
 
 Idempotency StorageControlConnectionIdempotencyPolicy::GetFolder(
-    google::storage::control::v2::GetFolderRequest const&) {
+    google::storage::control::v2::GetFolderRequest const& request) {
+  if (!request.request_id().empty()) return Idempotency::kIdempotent;
   return Idempotency::kIdempotent;
 }
 
@@ -55,12 +58,14 @@ Idempotency StorageControlConnectionIdempotencyPolicy::ListFolders(
 }
 
 Idempotency StorageControlConnectionIdempotencyPolicy::RenameFolder(
-    google::storage::control::v2::RenameFolderRequest const&) {
+    google::storage::control::v2::RenameFolderRequest const& request) {
+  if (!request.request_id().empty()) return Idempotency::kIdempotent;
   return Idempotency::kNonIdempotent;
 }
 
 Idempotency StorageControlConnectionIdempotencyPolicy::GetStorageLayout(
-    google::storage::control::v2::GetStorageLayoutRequest const&) {
+    google::storage::control::v2::GetStorageLayoutRequest const& request) {
+  if (!request.request_id().empty()) return Idempotency::kIdempotent;
   return Idempotency::kIdempotent;
 }