diff --git a/README.md b/README.md
index b42f787..6cc1600 100644
--- a/README.md
+++ b/README.md
@@ -73,7 +73,9 @@ uv sync
         "--directory",
         "<プロジェクトの絶対パス>",
         "run",
-        "main.py"
+        "-m"
+        "mcp_esa_server.server"
+
       ],
       "env": {
         "ESA_TEAM_NAME": "<your-team-name>",
diff --git a/docs/mcp_esa_server_usage.md b/docs/mcp_esa_server_usage.md
index 5cb0b75..8bfcde5 100644
--- a/docs/mcp_esa_server_usage.md
+++ b/docs/mcp_esa_server_usage.md
@@ -52,11 +52,11 @@ ESA_TEAM_NAME=your_team_name
 ## 4. サーバーの起動
 
 ```bash
-uv run mcp run main.py
+uv run mcp run src/mcp_esa_server/server.py
 ```
 または開発モード
 ```bash
-uv run mcp dev main.py
+uv run mcp dev src/mcp_esa_server/server.py
 ```
 
 サーバーはデフォルトで `http://localhost:6274` で起動し、MCPエンドポイントは `/mcp` です。
diff --git a/pyproject.toml b/pyproject.toml
index 31ecd90..a15a219 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,18 +1,30 @@
 [project]
 name = "mcp-esa-server"
-version = "0.1.0"
+version = "0.1.8"
 description = "MCP server for esa.io API"
-authors = [
-    {name = "Naoki Numaguchi", email = "redheru@gmail.com"},
+readme = "README.md"
+requires-python = ">=3.11"
+license = "MIT"
+classifiers = [
+    "Development Status :: 3 - Alpha",
+    "Intended Audience :: Developers",
+    "License :: OSI Approved :: MIT License",
+    "Programming Language :: Python :: 3.11",
+    "Programming Language :: Python :: 3.12",
+    "Programming Language :: Python :: 3.13",
 ]
 dependencies = [
     "requests",
     "python-dotenv",
     "mcp[cli]>=1.7.1",
 ]
-requires-python = ">=3.11"
-readme = "README.md"
-license = {text = "MIT"}
+
+[[project.authors]]
+name = "scnsh"
+
+[build-system]
+requires = ["hatchling"]
+build-backend = "hatchling.build"
 
 [project.optional-dependencies]
 dev = [
@@ -22,6 +34,16 @@ dev = [
     "pytest-mock>=3.14.0",
 ]
 
+[project.urls]
+Homepage = "https://github.com/scnsh/mcp-esa-server-python"
+Repository = "https://github.com/scnsh/mcp-esa-server-python"
+
+[project.scripts]
+mcp-esa-server = "mcp_esa_server:main"
+
+[tool.hatch.build.targets.wheel]
+packages = ["src/mcp_esa_server"]
+
 [tool.ruff]
 line-length = 120
 target-version = "py313" # プロジェクトで使用するPythonバージョンに合わせてください
diff --git a/src/mcp_esa_server/__init__.py b/src/mcp_esa_server/__init__.py
new file mode 100644
index 0000000..b42e3b0
--- /dev/null
+++ b/src/mcp_esa_server/__init__.py
@@ -0,0 +1,10 @@
+from . import server
+
+
+def main():
+    """このパッケージのメインエントリポイント"""
+    server.main()
+
+
+# パッケージレベルで公開する他のアイテム
+__all__ = ["main", "server"]
diff --git a/esa_client.py b/src/mcp_esa_server/esa_client.py
similarity index 98%
rename from esa_client.py
rename to src/mcp_esa_server/esa_client.py
index 1b0ed7e..0f0db1f 100644
--- a/esa_client.py
+++ b/src/mcp_esa_server/esa_client.py
@@ -2,9 +2,6 @@
 
 import requests
 
-# from dotenv import load_dotenv
-
-# load_dotenv()
 logger = logging.getLogger(__name__)
 
 
@@ -118,12 +115,14 @@ def delete_post(self, post_number: int):
 
 # Example usage (optional, for testing during development)
 if __name__ == "__main__":
+    import os
+
     from dotenv import load_dotenv
 
     load_dotenv()
     logging.basicConfig(level=logging.INFO)
     try:
-        client = EsaClient()
+        client = EsaClient(os.getenv("ESA_TOKEN"), os.getenv("ESA_TEAM_NAME"))
         logger.info(f"EsaClient initialized for team: {client.team_name}")
     except ValueError as e:
         logger.error(f"Initialization failed: {e}")
diff --git a/main.py b/src/mcp_esa_server/server.py
similarity index 95%
rename from main.py
rename to src/mcp_esa_server/server.py
index 1324bda..9c077e6 100644
--- a/main.py
+++ b/src/mcp_esa_server/server.py
@@ -1,13 +1,13 @@
 import logging
 import os
+import sys
 from typing import Annotated, Any
 
 from dotenv import load_dotenv
+from .esa_client import EsaClient
 from mcp.server.fastmcp import FastMCP
 from pydantic import Field
 
-from esa_client import EsaClient
-
 # Load environment variables from .env file
 load_dotenv()
 
@@ -15,16 +15,16 @@
 logging.basicConfig(level=logging.INFO)
 logger = logging.getLogger(__name__)
 
-# Create MCP instance
-mcp = FastMCP("esa-mcp-server")
-
 # Get environment variables
 esa_token = os.getenv("ESA_TOKEN")
 esa_team_name = os.getenv("ESA_TEAM_NAME")
 
-logger.info("Attempting to initialize EsaClient.")
-logger.info(f"ESA_TOKEN from env: {esa_token}")
-logger.info(f"ESA_TEAM_NAME from env: {esa_team_name}")
+logger.debug("Attempting to initialize EsaClient.")
+logger.debug(f"ESA_TOKEN from env (for EsaClient): {esa_token}")
+logger.debug(f"ESA_TEAM_NAME from env (for EsaClient): {esa_team_name}")
+
+# Create MCP instance
+mcp = FastMCP("esa-mcp-server")
 
 # Initialize EsaClient
 if not esa_token or not esa_team_name:
@@ -224,8 +224,11 @@ def posts_delete(post_number: int) -> dict[str, Any]:
         logger.error(f"Error deleting post {post_number}: {e}", exc_info=True)
         raise RuntimeError(f"Error deleting post: {e}") from e
 
+def main():
+    """MCPサーバーを起動するためのメイン関数"""
+    logger.info("Starting MCP server via main()...")
+    mcp.run()
 
 # Use mcp.run() to start the server when script is executed directly
 if __name__ == "__main__":
-    logger.info("Starting MCP server...")
-    mcp.run()
+    main()
diff --git a/tests/integration/test_esa_client_integration.py b/tests/integration/test_esa_client_integration.py
index b0d7017..1075487 100644
--- a/tests/integration/test_esa_client_integration.py
+++ b/tests/integration/test_esa_client_integration.py
@@ -6,7 +6,7 @@
 import requests
 from dotenv import load_dotenv
 
-from esa_client import EsaClient
+from src.mcp_esa_server.esa_client import EsaClient
 
 # Load environment variables from .env file
 load_dotenv()
diff --git a/tests/test_esa_client.py b/tests/test_esa_client.py
index c618791..6e68bdb 100644
--- a/tests/test_esa_client.py
+++ b/tests/test_esa_client.py
@@ -3,7 +3,7 @@
 import pytest
 import requests
 
-from esa_client import EsaClient
+from src.mcp_esa_server.esa_client import EsaClient
 
 
 @pytest.fixture
@@ -36,7 +36,7 @@ def test_esa_client_initialization_missing_team_name():
         EsaClient(token="test_token", team_name="")
 
 
-@patch("esa_client.requests.Session.request")
+@patch("src.mcp_esa_server.esa_client.requests.Session.request")
 def test_get_user_success(mock_request, client):
     "Test the get_user method success case."
     # Arrange: Configure the mock response
@@ -54,7 +54,7 @@ def test_get_user_success(mock_request, client):
     assert user_data == expected_user_data
 
 
-@patch("esa_client.requests.Session.request")
+@patch("src.mcp_esa_server.esa_client.requests.Session.request")
 def test_get_user_api_error(mock_request, client):
     "Test the get_user method handles API errors."
     # Arrange: Configure the mock to raise an HTTPError
@@ -68,7 +68,7 @@ def test_get_user_api_error(mock_request, client):
 # --- Tests for get_posts --- #
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_get_posts_success_no_params(mock_request, client):
     "Test get_posts success with no parameters."
     # Arrange
@@ -83,7 +83,7 @@ def test_get_posts_success_no_params(mock_request, client):
     assert posts_data == expected_response
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_get_posts_success_with_query(mock_request, client):
     "Test get_posts success with a search query."
     # Arrange
@@ -99,7 +99,7 @@ def test_get_posts_success_with_query(mock_request, client):
     assert posts_data == expected_response
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_get_posts_success_with_pagination(mock_request, client):
     "Test get_posts success with pagination parameters."
     # Arrange
@@ -116,7 +116,7 @@ def test_get_posts_success_with_pagination(mock_request, client):
     assert posts_data == expected_response
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_get_posts_success_with_all_params(mock_request, client):
     "Test get_posts success with all parameters."
     # Arrange
@@ -134,7 +134,7 @@ def test_get_posts_success_with_all_params(mock_request, client):
     assert posts_data == expected_response
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_get_posts_api_error(mock_request, client):
     "Test get_posts handles API errors from _request."
     # Arrange
@@ -148,7 +148,7 @@ def test_get_posts_api_error(mock_request, client):
 # --- Tests for get_post --- #
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_get_post_success(mock_request, client):
     "Test get_post success case."
     # Arrange
@@ -164,7 +164,7 @@ def test_get_post_success(mock_request, client):
     assert post_data == expected_response
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_get_post_api_error(mock_request, client):
     "Test get_post handles API errors from _request."
     # Arrange
@@ -179,7 +179,7 @@ def test_get_post_api_error(mock_request, client):
 # --- Tests for create_post (method to be added to EsaClient) ---
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_create_post_success(mock_request, client):
     """Test create_post successfully creates a post and returns its data."""
     # Arrange
@@ -195,7 +195,7 @@ def test_create_post_success(mock_request, client):
     assert result == expected_response
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_create_post_api_error(mock_request, client):
     """Test create_post handles API errors from _request."""
     # Arrange
@@ -210,7 +210,7 @@ def test_create_post_api_error(mock_request, client):
 # --- Tests for update_post (method to be added to EsaClient) ---
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_update_post_success(mock_request, client):
     """Test update_post successfully updates a post and returns its data."""
     # Arrange
@@ -227,7 +227,7 @@ def test_update_post_success(mock_request, client):
     assert result == expected_response
 
 
-@patch("esa_client.EsaClient._request")
+@patch("src.mcp_esa_server.esa_client.EsaClient._request")
 def test_update_post_api_error(mock_request, client):
     """Test update_post handles API errors from _request."""
     # Arrange
diff --git a/tests/test_main_tools.py b/tests/test_main_tools.py
index 0353608..b46e671 100644
--- a/tests/test_main_tools.py
+++ b/tests/test_main_tools.py
@@ -2,9 +2,7 @@
 
 import pytest
 
-# Assuming main.py is in the parent directory of tests, or path is configured
-# For this example, let's assume 'main' can be imported due to pyproject.toml settings or structure.
-from main import (
+from src.mcp_esa_server.server import (
     posts_create,
     posts_delete,
     posts_get_detail,
@@ -18,14 +16,14 @@
 @pytest.fixture
 def mock_esa_client_in_main():
     # Patch 'main.esa_client' which is used by the MCP tools
-    with patch("main.esa_client", new_callable=MagicMock) as mock_client:
+    with patch("src.mcp_esa_server.server.esa_client", new_callable=MagicMock) as mock_client:
         yield mock_client
 
 
 # Fixture to mock a non-initialized esa_client in main.py
 @pytest.fixture
 def mock_esa_client_none_in_main():
-    with patch("main.esa_client", None) as mock_client_none:
+    with patch("src.mcp_esa_server.server.esa_client", None) as mock_client_none:
         yield mock_client_none
 
 
diff --git a/uv.lock b/uv.lock
index b759f68..dd11041 100644
--- a/uv.lock
+++ b/uv.lock
@@ -261,8 +261,8 @@ cli = [
 
 [[package]]
 name = "mcp-esa-server"
-version = "0.1.0"
-source = { virtual = "." }
+version = "0.1.8"
+source = { editable = "." }
 dependencies = [
     { name = "mcp", extra = ["cli"] },
     { name = "python-dotenv" },