diff --git a/src/SPC/toolchain/ClangNativeToolchain.php b/src/SPC/toolchain/ClangNativeToolchain.php
index fb0bea46..aef844d7 100644
--- a/src/SPC/toolchain/ClangNativeToolchain.php
+++ b/src/SPC/toolchain/ClangNativeToolchain.php
@@ -10,6 +10,9 @@ use SPC\builder\macos\SystemUtil as MacOSSystemUtil;
 use SPC\exception\WrongUsageException;
 use SPC\util\GlobalEnvManager;
 
+/**
+ * Toolchain implementation for system clang compiler.
+ */
 class ClangNativeToolchain implements ToolchainInterface
 {
     public function initEnv(): void
@@ -20,6 +23,9 @@ class ClangNativeToolchain implements ToolchainInterface
         GlobalEnvManager::putenv('SPC_LINUX_DEFAULT_LD=ld');
     }
 
+    /**
+     * @throws WrongUsageException
+     */
     public function afterInit(): void
     {
         foreach (['CC', 'CXX', 'AR', 'LD'] as $env) {
diff --git a/src/SPC/util/GlobalEnvManager.php b/src/SPC/util/GlobalEnvManager.php
index 23ae242d..f5dafea2 100644
--- a/src/SPC/util/GlobalEnvManager.php
+++ b/src/SPC/util/GlobalEnvManager.php
@@ -15,6 +15,8 @@ class GlobalEnvManager
 {
     private static array $env_cache = [];
 
+    private static bool $initialized = false;
+
     public static function getInitializedEnv(): array
     {
         return self::$env_cache;
@@ -28,6 +30,9 @@ class GlobalEnvManager
      */
     public static function init(): void
     {
+        if (self::$initialized) {
+            return;
+        }
         // Check pre-defined env vars exists
         if (getenv('BUILD_ROOT_PATH') === false) {
             throw new RuntimeException('You must include src/globals/internal-env.php before using GlobalEnvManager');
@@ -85,6 +90,7 @@ class GlobalEnvManager
                 self::putenv("{$k}={$v}");
             }
         }
+        self::$initialized = true;
     }
 
     public static function putenv(string $val): void