diff --git a/main.py b/main.py
index 51dcd9e8..ed1356a3 100644
--- a/main.py
+++ b/main.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 """
 Entry point script for the Deer project.
 """
diff --git a/server.py b/server.py
index 62be824f..a7c424ea 100644
--- a/server.py
+++ b/server.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 """
 Server script for running the Deer API.
 """
diff --git a/src/__init__.py b/src/__init__.py
index e69de29b..a74d8cf9 100644
--- a/src/__init__.py
+++ b/src/__init__.py
@@ -0,0 +1,3 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
diff --git a/src/agents/__init__.py b/src/agents/__init__.py
index 1c6d9111..c235a05e 100644
--- a/src/agents/__init__.py
+++ b/src/agents/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .agents import research_agent, coder_agent
 
 __all__ = ["research_agent", "coder_agent"]
diff --git a/src/agents/agents.py b/src/agents/agents.py
index 477b7e27..2a4d3303 100644
--- a/src/agents/agents.py
+++ b/src/agents/agents.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from langgraph.prebuilt import create_react_agent
 
 from src.prompts import apply_prompt_template
diff --git a/src/config/__init__.py b/src/config/__init__.py
index f1ad7696..c4639c1e 100644
--- a/src/config/__init__.py
+++ b/src/config/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .tools import SEARCH_MAX_RESULTS, SELECTED_SEARCH_ENGINE, SearchEngine
 from .loader import load_yaml_config
 from .questions import BUILT_IN_QUESTIONS, BUILT_IN_QUESTIONS_ZH_CN
diff --git a/src/config/agents.py b/src/config/agents.py
index 62be2c1e..df65b2af 100644
--- a/src/config/agents.py
+++ b/src/config/agents.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from typing import Literal
 
 # Define available LLM types
diff --git a/src/config/configuration.py b/src/config/configuration.py
index 8912b464..8df7a7f5 100644
--- a/src/config/configuration.py
+++ b/src/config/configuration.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import os
 from dataclasses import dataclass, fields
 from typing import Any, Optional
diff --git a/src/config/loader.py b/src/config/loader.py
index dff0ed85..a6edfe50 100644
--- a/src/config/loader.py
+++ b/src/config/loader.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import os
 import yaml
 from typing import Dict, Any
diff --git a/src/config/questions.py b/src/config/questions.py
index 3254c131..21a906c6 100644
--- a/src/config/questions.py
+++ b/src/config/questions.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 """
 Built-in questions for Deer.
 """
diff --git a/src/config/tools.py b/src/config/tools.py
index 8b3e5263..37ee9d68 100644
--- a/src/config/tools.py
+++ b/src/config/tools.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import os
 import enum
 from dotenv import load_dotenv
diff --git a/src/crawler/__init__.py b/src/crawler/__init__.py
index 5303aa0c..4f6a6e7f 100644
--- a/src/crawler/__init__.py
+++ b/src/crawler/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .article import Article
 from .crawler import Crawler
 
diff --git a/src/crawler/article.py b/src/crawler/article.py
index ba088b41..fd0c95e6 100644
--- a/src/crawler/article.py
+++ b/src/crawler/article.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import re
 from urllib.parse import urljoin
 
diff --git a/src/crawler/crawler.py b/src/crawler/crawler.py
index eb87dcd1..fe7ddfce 100644
--- a/src/crawler/crawler.py
+++ b/src/crawler/crawler.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import sys
 
 from .article import Article
diff --git a/src/crawler/jina_client.py b/src/crawler/jina_client.py
index a3ec7327..8cd81ed1 100644
--- a/src/crawler/jina_client.py
+++ b/src/crawler/jina_client.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 import os
 
diff --git a/src/crawler/readability_extractor.py b/src/crawler/readability_extractor.py
index 7bf63e09..a3a22d05 100644
--- a/src/crawler/readability_extractor.py
+++ b/src/crawler/readability_extractor.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from readabilipy import simple_json_from_html_string
 
 from .article import Article
diff --git a/src/graph/__init__.py b/src/graph/__init__.py
index 536aa4ce..ec13d9a5 100644
--- a/src/graph/__init__.py
+++ b/src/graph/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .builder import build_graph
 
 __all__ = [
diff --git a/src/graph/builder.py b/src/graph/builder.py
index 8425d432..fcb4f394 100644
--- a/src/graph/builder.py
+++ b/src/graph/builder.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from langgraph.graph import StateGraph, START, END
 from langgraph.checkpoint.memory import MemorySaver
 from .types import State
diff --git a/src/graph/nodes.py b/src/graph/nodes.py
index 559abf07..4a7a5ca2 100644
--- a/src/graph/nodes.py
+++ b/src/graph/nodes.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 import json
 from typing import Literal, Annotated
diff --git a/src/graph/types.py b/src/graph/types.py
index 4d8a9194..71a208e1 100644
--- a/src/graph/types.py
+++ b/src/graph/types.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import operator
 
 from langgraph.graph import MessagesState
diff --git a/src/llms/__init__.py b/src/llms/__init__.py
index e69de29b..a74d8cf9 100644
--- a/src/llms/__init__.py
+++ b/src/llms/__init__.py
@@ -0,0 +1,3 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
diff --git a/src/llms/llm.py b/src/llms/llm.py
index 767cd992..ca5dc75a 100644
--- a/src/llms/llm.py
+++ b/src/llms/llm.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from langchain_openai import ChatOpenAI
 from src.config import load_yaml_config
 from pathlib import Path
diff --git a/src/prompts/__init__.py b/src/prompts/__init__.py
index 3831b7ac..e05eaae8 100644
--- a/src/prompts/__init__.py
+++ b/src/prompts/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .template import apply_prompt_template, get_prompt_template
 
 __all__ = [
diff --git a/src/prompts/planner_model.py b/src/prompts/planner_model.py
index dc65913c..615d7017 100644
--- a/src/prompts/planner_model.py
+++ b/src/prompts/planner_model.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from pydantic import BaseModel, Field
 from typing import List, Optional
 from enum import Enum
diff --git a/src/prompts/template.py b/src/prompts/template.py
index e0c022a6..beafe272 100644
--- a/src/prompts/template.py
+++ b/src/prompts/template.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import os
 import dataclasses
 from datetime import datetime
diff --git a/src/server/__init__.py b/src/server/__init__.py
index 34f275ed..b5f0b024 100644
--- a/src/server/__init__.py
+++ b/src/server/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .app import app
 
 __all__ = ["app"]
diff --git a/src/server/app.py b/src/server/app.py
index fe1b4943..1eca6549 100644
--- a/src/server/app.py
+++ b/src/server/app.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import json
 import logging
 from typing import List, cast
diff --git a/src/server/chat_request.py b/src/server/chat_request.py
index 8a44ee35..55d24720 100644
--- a/src/server/chat_request.py
+++ b/src/server/chat_request.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from typing import List, Optional, Union
 
 from pydantic import BaseModel, Field
diff --git a/src/tools/__init__.py b/src/tools/__init__.py
index 1d34af81..774938f7 100644
--- a/src/tools/__init__.py
+++ b/src/tools/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 from .crawl import crawl_tool
 from .python_repl import python_repl_tool
 from .search import (
diff --git a/src/tools/crawl.py b/src/tools/crawl.py
index fa78c5b0..9b1aa972 100644
--- a/src/tools/crawl.py
+++ b/src/tools/crawl.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 from typing import Annotated
 
diff --git a/src/tools/decorators.py b/src/tools/decorators.py
index 0cf4e9e6..a37e82eb 100644
--- a/src/tools/decorators.py
+++ b/src/tools/decorators.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 import functools
 from typing import Any, Callable, Type, TypeVar
diff --git a/src/tools/python_repl.py b/src/tools/python_repl.py
index feb05db0..4b9c0aba 100644
--- a/src/tools/python_repl.py
+++ b/src/tools/python_repl.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 from typing import Annotated
 from langchain_core.tools import tool
diff --git a/src/tools/search.py b/src/tools/search.py
index 9cf8dd29..42441ddc 100644
--- a/src/tools/search.py
+++ b/src/tools/search.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 import os
 from langchain_community.tools.tavily_search import TavilySearchResults
diff --git a/src/utils/__init__.py b/src/utils/__init__.py
index 7507b9d7..baffcc7a 100644
--- a/src/utils/__init__.py
+++ b/src/utils/__init__.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 """
 工具函数包
 """
diff --git a/src/utils/json_utils.py b/src/utils/json_utils.py
index 9b0d2fb1..f9c10ff3 100644
--- a/src/utils/json_utils.py
+++ b/src/utils/json_utils.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 import json
 import json_repair
diff --git a/src/workflow.py b/src/workflow.py
index a6abd766..46437e40 100644
--- a/src/workflow.py
+++ b/src/workflow.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import logging
 from src.graph import build_graph
 
diff --git a/tests/integration/test_crawler.py b/tests/integration/test_crawler.py
index 2672d2d8..e4584bd8 100644
--- a/tests/integration/test_crawler.py
+++ b/tests/integration/test_crawler.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import pytest
 from src.crawler import Crawler
 
diff --git a/tests/integration/test_python_repl_tool.py b/tests/integration/test_python_repl_tool.py
index becb3d61..bad03336 100644
--- a/tests/integration/test_python_repl_tool.py
+++ b/tests/integration/test_python_repl_tool.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import pytest
 from src.tools.python_repl import python_repl_tool
 
diff --git a/tests/integration/test_template.py b/tests/integration/test_template.py
index d39f9977..04eb4d73 100644
--- a/tests/integration/test_template.py
+++ b/tests/integration/test_template.py
@@ -1,3 +1,6 @@
+# Copyright (c) 2025 Bytedance Ltd. and/or its affiliates
+# SPDX-License-Identifier: MIT
+
 import pytest
 from src.prompts.template import get_prompt_template, apply_prompt_template