diff --git a/src/protocols/ai.js b/src/protocols/ai.js
index 22a2ae8..bc68053 100644
--- a/src/protocols/ai.js
+++ b/src/protocols/ai.js
@@ -1,3 +1,21 @@
+/**
+ * Xget - High-performance acceleration engine for developer resources
+ * Copyright (C) 2025 Xi Xu
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
 /**
  * AI Inference protocol handler for Xget
  */
diff --git a/src/protocols/docker.js b/src/protocols/docker.js
index 5a20615..9beb0f3 100644
--- a/src/protocols/docker.js
+++ b/src/protocols/docker.js
@@ -1,3 +1,21 @@
+/**
+ * Xget - High-performance acceleration engine for developer resources
+ * Copyright (C) 2025 Xi Xu
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
 /**
  * Docker/OCI Registry protocol handler for Xget
  */
diff --git a/src/protocols/git.js b/src/protocols/git.js
index 7cc93eb..cb8e973 100644
--- a/src/protocols/git.js
+++ b/src/protocols/git.js
@@ -1,3 +1,21 @@
+/**
+ * Xget - High-performance acceleration engine for developer resources
+ * Copyright (C) 2025 Xi Xu
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
 /**
  * Git protocol handler for Xget
  */
diff --git a/src/utils/performance.js b/src/utils/performance.js
index d8eb5ec..a505ef3 100644
--- a/src/utils/performance.js
+++ b/src/utils/performance.js
@@ -1,3 +1,21 @@
+/**
+ * Xget - High-performance acceleration engine for developer resources
+ * Copyright (C) 2025 Xi Xu
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
 /**
  * Performance monitoring utilities for Xget
  */
diff --git a/src/utils/security.js b/src/utils/security.js
index 4eb8c33..e37535c 100644
--- a/src/utils/security.js
+++ b/src/utils/security.js
@@ -1,3 +1,21 @@
+/**
+ * Xget - High-performance acceleration engine for developer resources
+ * Copyright (C) 2025 Xi Xu
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
 /**
  * Security utility functions for Xget
  */
diff --git a/src/utils/validation.js b/src/utils/validation.js
index 2353ece..a2f623c 100644
--- a/src/utils/validation.js
+++ b/src/utils/validation.js
@@ -1,3 +1,21 @@
+/**
+ * Xget - High-performance acceleration engine for developer resources
+ * Copyright (C) 2025 Xi Xu
+ *
+ * This program is free software: you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation, either version 3 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
+ * GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program. If not, see <https://www.gnu.org/licenses/>.
+ */
+
 /**
  * Request validation utilities for Xget
  */