diff --git a/ci/otel_collector/BUILD.bazel b/ci/otel_collector/BUILD.bazel
index 4f1adaf496ae2..3c90872bda823 100644
--- a/ci/otel_collector/BUILD.bazel
+++ b/ci/otel_collector/BUILD.bazel
@@ -21,6 +21,7 @@ cc_library(
     srcs = ["otel_collector.cc"],
     hdrs = ["otel_collector.h"],
     deps = [
+        "//:common",
         "//protos/google/cloud/opentelemetry/testing:observability_verification_cc_grpc",
         "//protos/google/cloud/opentelemetry/testing:observability_verification_cc_proto",
         "@googleapis//google/monitoring/v3:monitoring_cc_grpc",
diff --git a/ci/otel_collector/CMakeLists.txt b/ci/otel_collector/CMakeLists.txt
index 313ac861ead35..58630a4fe0717 100644
--- a/ci/otel_collector/CMakeLists.txt
+++ b/ci/otel_collector/CMakeLists.txt
@@ -20,10 +20,11 @@ add_library(otel_collector otel_collector.cc otel_collector.h)
 target_link_libraries(
     otel_collector PUBLIC google_cloud_cpp_opentelemetry_testing_protos
                           google-cloud-cpp::monitoring_protos gRPC::grpc++)
-target_include_directories(otel_collector PUBLIC ${PROJECT_SOURCE_DIR})
+target_include_directories(otel_collector PUBLIC ${PROJECT_SOURCE_DIR}
+                                                 ${PROJECT_BINARY_DIR})
 google_cloud_cpp_add_common_options(otel_collector NO_WARNINGS)
 
 google_cloud_cpp_add_executable(target "otel_collector_main"
                                 "otel_collector_main.cc")
-target_link_libraries(otel_collector_main PRIVATE otel_collector gRPC::grpc++)
-google_cloud_cpp_add_common_options(otel_collector_main NO_WARNINGS)
+target_link_libraries(${target} PRIVATE otel_collector gRPC::grpc++)
+google_cloud_cpp_add_common_options(${target} NO_WARNINGS)
diff --git a/ci/otel_collector/otel_collector.cc b/ci/otel_collector/otel_collector.cc
index 36251f17e467e..8e0884d13b0d9 100644
--- a/ci/otel_collector/otel_collector.cc
+++ b/ci/otel_collector/otel_collector.cc
@@ -16,6 +16,7 @@
 
 namespace google {
 namespace cloud {
+GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_BEGIN
 namespace testing_util {
 
 grpc::Status OtelCollectorServer::CreateTimeSeries(
@@ -68,5 +69,6 @@ void OtelCollectorServer::Clear() {
 }
 
 }  // namespace testing_util
+GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_END
 }  // namespace cloud
 }  // namespace google
diff --git a/ci/otel_collector/otel_collector.h b/ci/otel_collector/otel_collector.h
index 145c5b31fdd8a..43de850bd7b18 100644
--- a/ci/otel_collector/otel_collector.h
+++ b/ci/otel_collector/otel_collector.h
@@ -15,6 +15,7 @@
 #ifndef GOOGLE_CLOUD_CPP_CI_OTEL_COLLECTOR_OTEL_COLLECTOR_H
 #define GOOGLE_CLOUD_CPP_CI_OTEL_COLLECTOR_OTEL_COLLECTOR_H
 
+#include "google/cloud/version.h"
 #include "protos/google/cloud/opentelemetry/testing/observability_verification.grpc.pb.h"
 #include <google/monitoring/v3/metric_service.grpc.pb.h>
 #include <grpcpp/grpcpp.h>
@@ -23,6 +24,7 @@
 
 namespace google {
 namespace cloud {
+GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_BEGIN
 namespace testing_util {
 
 /**
@@ -71,6 +73,7 @@ class OtelCollectorServer final
 };
 
 }  // namespace testing_util
+GOOGLE_CLOUD_CPP_INLINE_NAMESPACE_END
 }  // namespace cloud
 }  // namespace google