diff --git a/base/BUILD.gn b/base/BUILD.gn
index 0afa1d812bc1..1a3732e8f123 100644
--- a/base/BUILD.gn
+++ b/base/BUILD.gn
@@ -109,7 +109,7 @@ if (is_apple) {
 # ../../third_party/libevent/signal.c:43:10: fatal error: 'sys/queue.h' file not found
 # #include <sys/queue.h>
 # Determines whether libevent should be dep.
-if (is_cobalt && is_starboard && use_custom_libc) {
+if (is_cobalt && is_cobalt_hermetic_build) {
   dep_libevent = false
 } else {
   dep_libevent = !is_fuchsia && !is_win && !is_mac && !is_nacl
@@ -209,7 +209,6 @@ buildflag_header("ios_cronet_buildflags") {
 }
 
 enable_message_pump_epoll = is_linux || is_chromeos || is_android
-
 buildflag_header("message_pump_buildflags") {
   header = "message_pump_buildflags.h"
   header_dir = "base/message_loop"
@@ -1025,7 +1024,7 @@ component("base") {
     ]
   }
 
-  if (is_cobalt && is_starboard && use_custom_libc) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     sources -= [
       "debug/proc_maps_linux.cc",
       "debug/proc_maps_linux.h",
@@ -1118,8 +1117,7 @@ component("base") {
     "//third_party/abseil-cpp:absl",
   ]
 
-  if (is_cobalt && is_starboard && use_custom_libc &&
-      current_toolchain == cobalt_toolchain) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     deps -= [ "//base/allocator/partition_allocator:raw_ptr" ]
     deps += [ "//starboard:starboard_group" ]
   }
@@ -1157,7 +1155,7 @@ component("base") {
         "allocator/partition_allocator/shim/allocator_shim_default_dispatch_to_partition_alloc.h",
       ]
     }
-    if (is_cobalt && is_starboard && use_custom_libc) {
+    if (is_cobalt && is_cobalt_hermetic_build) {
       sources -= [
         "allocator/partition_allocator/shim/allocator_shim_default_dispatch_to_partition_alloc.cc",
         "allocator/partition_allocator/shim/allocator_shim_default_dispatch_to_partition_alloc.h",
@@ -1192,7 +1190,7 @@ component("base") {
     #                           ^
     # ../../third_party/musl/include/malloc.h:19:8: note: previous declaration is here
     # size_t malloc_usable_size(void *);
-    if (is_cobalt && is_starboard && use_custom_libc) {
+    if (is_cobalt && is_cobalt_hermetic_build) {
       sources -= [
         "allocator/partition_allocator/shim/allocator_shim_override_cpp_symbols.h",
         "allocator/partition_allocator/shim/allocator_shim_override_glibc_weak_symbols.h",
@@ -1703,8 +1701,7 @@ component("base") {
     }
 
     # TODO: b/384652502 - Cobalt: Fix compiler errors building hermetically.
-    if (is_cobalt && is_starboard && use_custom_libc &&
-        current_toolchain == cobalt_toolchain) {
+    if (is_cobalt && is_cobalt_hermetic_build) {
       sources -= [
         "base_paths_posix.h",
         "memory/madv_free_discardable_memory_allocator_posix.cc",
@@ -1735,7 +1732,7 @@ component("base") {
       ]
     }
 
-    if (is_cobalt && is_starboard && use_custom_libc) {
+    if (is_cobalt && is_cobalt_hermetic_build) {
       sources -= [
         "process/process_metrics_posix.cc",
         "sync_socket_posix.cc",
@@ -1761,7 +1758,7 @@ component("base") {
       ]
     }
 
-    if (is_cobalt && is_starboard && use_custom_libc) {
+    if (is_cobalt && is_cobalt_hermetic_build) {
       sources -= [
         "native_library_posix.cc",
         "posix/can_lower_nice_to.cc",
diff --git a/base/allocator/partition_allocator/BUILD.gn b/base/allocator/partition_allocator/BUILD.gn
index 2d455bf40248..37d188ab7163 100644
--- a/base/allocator/partition_allocator/BUILD.gn
+++ b/base/allocator/partition_allocator/BUILD.gn
@@ -233,7 +233,7 @@ component("partition_alloc") {
     ]
 
     # TODO: b/384652502 - Cobalt: Fix compiler errors building hermetically.
-    if (is_cobalt && is_starboard && use_custom_libc && current_toolchain == cobalt_toolchain) {
+    if (is_cobalt && is_cobalt_hermetic_build) {
         sources -= [ "partition_alloc_base/rand_util_posix.cc" ]
     }
 
@@ -330,7 +330,7 @@ component("partition_alloc") {
     deps += [ "//third_party/android_ndk:cpu_features" ]
   }
 
-  if (is_cobalt && is_starboard && use_custom_libc && current_toolchain == cobalt_toolchain) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
       deps += [ "//starboard:starboard_group" ]
   }
   if (is_fuchsia) {
diff --git a/build/config/c++/BUILD.gn b/build/config/c++/BUILD.gn
index 2f923082cae2..c92530c046d9 100644
--- a/build/config/c++/BUILD.gn
+++ b/build/config/c++/BUILD.gn
@@ -72,8 +72,7 @@ config("runtime_library") {
       "-isystem" + rebase_path("$libcxx_prefix/include", root_build_dir),
       "-isystem" + rebase_path("$libcxxabi_prefix/include", root_build_dir),
     ]
-    if (is_cobalt && is_starboard && use_custom_libc &&
-        current_toolchain == cobalt_toolchain) {
+    if (is_cobalt && is_cobalt_hermetic_build) {
       cflags_cc += [
         "-isystem" + rebase_path("//third_party/musl/include", root_build_dir),
         "-isystem" +
@@ -109,8 +108,7 @@ config("runtime_library") {
         "m",
         "rt",
       ]
-      if (is_cobalt && is_starboard && use_custom_libc &&
-          current_toolchain == cobalt_toolchain) {
+      if (is_cobalt && is_cobalt_hermetic_build) {
         libs -= [
           "c",
           "rt",
diff --git a/buildtools/third_party/libc++/BUILD.gn b/buildtools/third_party/libc++/BUILD.gn
index 21334c2d9770..ad91e311c07a 100644
--- a/buildtools/third_party/libc++/BUILD.gn
+++ b/buildtools/third_party/libc++/BUILD.gn
@@ -58,8 +58,7 @@ target(_libcxx_target_type, "libc++") {
     "//build/config:common_deps",
     "//third_party/catapult/devil:devil",
   ]
-  if (is_cobalt && is_starboard && use_custom_libc &&
-      current_toolchain == cobalt_toolchain) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     visibility += [ "//starboard:starboard_group" ]
   }
 
@@ -124,8 +123,7 @@ target(_libcxx_target_type, "libc++") {
     "trunk/src/verbose_abort.cpp",
   ]
 
-  if (is_cobalt && is_starboard && use_custom_libc &&
-      current_toolchain == cobalt_toolchain) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     # TODO: b/384652502 - Cobalt: Fix compiler errors building hermetically.
     sources -= [ "trunk/src/atomic.cpp" ]
   }
@@ -226,8 +224,7 @@ target(_libcxx_target_type, "libc++") {
     }
   }
 
-  if (is_cobalt && is_starboard && current_toolchain == cobalt_toolchain &&
-      use_custom_libc) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     deps += [
       "//third_party/llvm-project/compiler-rt:compiler_rt",
       "//third_party/musl:c",
diff --git a/buildtools/third_party/libc++abi/BUILD.gn b/buildtools/third_party/libc++abi/BUILD.gn
index 34f36d0f94c7..cd49e5f5de8c 100644
--- a/buildtools/third_party/libc++abi/BUILD.gn
+++ b/buildtools/third_party/libc++abi/BUILD.gn
@@ -16,8 +16,7 @@ source_set("libc++abi") {
   } else {
     visibility = [ "//buildtools/third_party/libc++" ]
   }
-  if (is_cobalt && is_starboard && use_custom_libc &&
-      current_toolchain == cobalt_toolchain) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     visibility += [ "//starboard:starboard_group" ]
   }
 
@@ -28,7 +27,7 @@ source_set("libc++abi") {
     deps = [ "//buildtools/third_party/libunwind" ]
   }
 
-  if (is_cobalt && is_starboard && use_custom_libc && current_toolchain == cobalt_toolchain) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     deps = [ "//third_party/musl:c" ]
   }
 
diff --git a/cobalt/build/configs/BUILD.gn b/cobalt/build/configs/BUILD.gn
index 71f4b359579f..bc6de5326d47 100644
--- a/cobalt/build/configs/BUILD.gn
+++ b/cobalt/build/configs/BUILD.gn
@@ -22,8 +22,7 @@ config("cobalt_config") {
   ]
   if (current_toolchain == starboard_toolchain) {
     configs += [ "//${starboard_path}/platform_configuration" ]
-  } else if (is_starboard && use_custom_libc &&
-             current_toolchain == cobalt_toolchain) {
+  } else if (is_cobalt_hermetic_build) {
     configs += [
       "//starboard/build/config/modular/x64",
       "//starboard/build/config:starboard",
diff --git a/cobalt/build/configs/modular_variables.gni b/cobalt/build/configs/modular_variables.gni
index 86cf8bbe13c8..0775b2c29395 100644
--- a/cobalt/build/configs/modular_variables.gni
+++ b/cobalt/build/configs/modular_variables.gni
@@ -16,3 +16,6 @@ declare_args() {
   # TODO: b/371241293 - Remove this variable when the hermetic toolchain is setup
   use_custom_libc = false
 }
+
+is_cobalt_hermetic_build =
+    is_starboard && use_custom_libc && current_toolchain == cobalt_toolchain
diff --git a/starboard/BUILD.gn b/starboard/BUILD.gn
index 3b5b4312973f..6226444300c7 100644
--- a/starboard/BUILD.gn
+++ b/starboard/BUILD.gn
@@ -111,7 +111,7 @@ if (!is_cobalt) {
       "//starboard/client_porting/eztime",
     ]
 
-    if (sb_is_modular && current_toolchain == cobalt_toolchain) {
+    if (is_cobalt_hermetic_build) {
       public_deps += [
         "//third_party/llvm-project/compiler-rt:compiler_rt",
         "//third_party/llvm-project/libcxx:cxx",
@@ -177,8 +177,7 @@ if (!is_cobalt) {
         "//starboard/client_porting/eztime",
       ]
 
-      if (sb_is_modular && use_custom_libc &&
-          current_toolchain == cobalt_toolchain) {
+      if (is_cobalt_hermetic_build) {
         public_deps += [
           "//buildtools/third_party/libc++",
           "//buildtools/third_party/libc++abi",
diff --git a/starboard/shared/modular/BUILD.gn b/starboard/shared/modular/BUILD.gn
index f5648939f1b1..1da182f53264 100644
--- a/starboard/shared/modular/BUILD.gn
+++ b/starboard/shared/modular/BUILD.gn
@@ -12,6 +12,8 @@
 # See the License for the specific language governing permissions and
 # limitations under the License.
 
+import("//cobalt/build/configs/modular_variables.gni")
+
 # TODO: b/315170518 - Revert to static library after fixing
 # symbol visibility issues for windows based modular platform builds.
 if ((sb_is_modular || sb_is_evergreen_compatible) &&
@@ -44,8 +46,7 @@ if ((sb_is_modular || sb_is_evergreen_compatible) &&
   }
 }
 
-if (sb_is_modular && !sb_is_evergreen &&
-    current_toolchain == cobalt_toolchain) {
+if (is_cobalt_hermetic_build && !sb_is_evergreen) {
   source_set("cobalt_layer_posix_abi_wrappers") {
     sources = [
       "cobalt_layer_posix_directory_abi_wrappers.cc",
diff --git a/third_party/abseil-cpp/absl/base/BUILD.gn b/third_party/abseil-cpp/absl/base/BUILD.gn
index 3045cc970f0b..fb098cd94ae7 100644
--- a/third_party/abseil-cpp/absl/base/BUILD.gn
+++ b/third_party/abseil-cpp/absl/base/BUILD.gn
@@ -42,7 +42,7 @@ absl_source_set("raw_logging_internal") {
     ":log_severity",
   ]
   visibility = [ "//third_party/abseil-cpp/absl/*" ]
-  if (is_cobalt && is_starboard && use_custom_libc) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     public_deps += [ "//starboard:starboard_headers_only" ]
   }
 }
diff --git a/third_party/boringssl/BUILD.gn b/third_party/boringssl/BUILD.gn
index de60e3957353..e45861dc736d 100644
--- a/third_party/boringssl/BUILD.gn
+++ b/third_party/boringssl/BUILD.gn
@@ -168,7 +168,7 @@ component("boringssl") {
   # config is forwarded to callers. In particular, boringssl_crypto_tests
   # requires it.
   public_deps = [ ":boringssl_asm" ]
-  if (is_cobalt && is_starboard && use_custom_libc) {
+  if (is_cobalt && is_cobalt_hermetic_build) {
     public_deps += [ "//starboard/common", "//starboard:starboard_headers_only"  ]
   }