diff --git a/src/podcast/graph/audio_mixer_node.py b/src/podcast/graph/audio_mixer_node.py
index c08ca63..a7570f6 100644
--- a/src/podcast/graph/audio_mixer_node.py
+++ b/src/podcast/graph/audio_mixer_node.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 
 from src.podcast.graph.state import PodcastState
diff --git a/src/podcast/graph/builder.py b/src/podcast/graph/builder.py
index 8914215..55c1498 100644
--- a/src/podcast/graph/builder.py
+++ b/src/podcast/graph/builder.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from langgraph.graph import END, START, StateGraph
 
 from .audio_mixer_node import audio_mixer_node
diff --git a/src/podcast/graph/script_writer_node.py b/src/podcast/graph/script_writer_node.py
index c4ffa86..fdbc741 100644
--- a/src/podcast/graph/script_writer_node.py
+++ b/src/podcast/graph/script_writer_node.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 
 from langchain.schema import HumanMessage, SystemMessage
diff --git a/src/podcast/graph/state.py b/src/podcast/graph/state.py
index 2f8da05..07f27c7 100644
--- a/src/podcast/graph/state.py
+++ b/src/podcast/graph/state.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from typing import Optional
 
 from langgraph.graph import MessagesState
diff --git a/src/podcast/graph/tts_node.py b/src/podcast/graph/tts_node.py
index 6be784b..056916c 100644
--- a/src/podcast/graph/tts_node.py
+++ b/src/podcast/graph/tts_node.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import base64
 import logging
 import os
diff --git a/src/podcast/types.py b/src/podcast/types.py
index 34a6887..4e04627 100644
--- a/src/podcast/types.py
+++ b/src/podcast/types.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from typing import Literal
 
 from pydantic import BaseModel, Field