diff --git a/pyproject.toml b/pyproject.toml
index 5b5ac7a..4b4790c 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -72,6 +72,7 @@ dependencies = [
   "parse==1.20.2",
   "parso==0.8.4",
   "pathable==0.4.4",
+  "platformdirs==4.5.0",
   "pluggy==1.6.0",
   "pycparser==2.23",
   "pydantic==2.11.7",
diff --git a/src/seclab_taskflow_agent/mcp_servers/codeql/mcp_server.py b/src/seclab_taskflow_agent/mcp_servers/codeql/mcp_server.py
index d692bdc..331ac67 100644
--- a/src/seclab_taskflow_agent/mcp_servers/codeql/mcp_server.py
+++ b/src/seclab_taskflow_agent/mcp_servers/codeql/mcp_server.py
@@ -20,10 +20,11 @@
 import re
 from urllib.parse import urlparse, unquote
 import zipfile
+from seclab_taskflow_agent.path_utils import mcp_data_dir
 
 mcp = FastMCP("CodeQL")
 
-CODEQL_DBS_BASE_PATH = Path(os.getenv('CODEQL_DBS_BASE_PATH', default='/workspaces'))
+CODEQL_DBS_BASE_PATH = mcp_data_dir('seclab-taskflow-agent', 'codeql', 'CODEQL_DBS_BASE_PATH')
 
 # tool name -> templated query lookup for supported languages
 TEMPLATED_QUERY_PATHS = {
diff --git a/src/seclab_taskflow_agent/mcp_servers/logbook/logbook.py b/src/seclab_taskflow_agent/mcp_servers/logbook/logbook.py
index 67b8c8f..8c8bec0 100644
--- a/src/seclab_taskflow_agent/mcp_servers/logbook/logbook.py
+++ b/src/seclab_taskflow_agent/mcp_servers/logbook/logbook.py
@@ -12,14 +12,13 @@
 from fastmcp import FastMCP # move to FastMCP 2.0
 import json
 from pathlib import Path
-import os
+from seclab_taskflow_agent.path_utils import mcp_data_dir
 
 mcp = FastMCP("Logbook")
 
 LOG = {}
 
-LOGBOOK = Path(__file__).parent.resolve() / Path(os.getenv('LOGBOOK_STATE_DIR', default='./')) / Path("logbook.json")
-
+LOGBOOK = mcp_data_dir('seclab-taskflow-agent', 'logbook', 'LOGBOOK_STATE_DIR') / Path("logbook.json")
 
 def ensure_log():
     global LOG
diff --git a/src/seclab_taskflow_agent/mcp_servers/memcache/memcache.py b/src/seclab_taskflow_agent/mcp_servers/memcache/memcache.py
index 1a527fb..f8b706c 100644
--- a/src/seclab_taskflow_agent/mcp_servers/memcache/memcache.py
+++ b/src/seclab_taskflow_agent/mcp_servers/memcache/memcache.py
@@ -16,6 +16,7 @@
 from typing import Any
 from .memcache_backend.dictionary_file import MemcacheDictionaryFileBackend
 from .memcache_backend.sqlite import SqliteBackend
+from seclab_taskflow_agent.path_utils import mcp_data_dir
 
 mcp = FastMCP("Memcache")
 
@@ -24,10 +25,7 @@
     'sqlite': SqliteBackend,
 }
 
-# if MEMCACHE_STATE_DIR contains an absolute path we WANT the user to be able
-# to override the relative path in that case this path join will return
-# /MEMCACHE_STATE_DIR/memory.json
-MEMORY = Path(__file__).parent.resolve() / Path(os.getenv('MEMCACHE_STATE_DIR', default='./'))
+MEMORY = mcp_data_dir('seclab-taskflow-agent', 'memcache', 'MEMCACHE_STATE_DIR')
 BACKEND = os.getenv('MEMCACHE_BACKEND', default='sqlite')
 
 backend = backends.get(BACKEND)(str(MEMORY))
diff --git a/src/seclab_taskflow_agent/path_utils.py b/src/seclab_taskflow_agent/path_utils.py
new file mode 100644
index 0000000..1175191
--- /dev/null
+++ b/src/seclab_taskflow_agent/path_utils.py
@@ -0,0 +1,33 @@
+# SPDX-FileCopyrightText: 2025 GitHub
+# SPDX-License-Identifier: MIT
+
+import platformdirs
+import os
+from pathlib import Path
+
+
+def mcp_data_dir(packagename: str, mcpname: str, env_override: str | None) -> Path:
+    """
+    Create a directory for an MCP to store its data.
+
+    Parameters:
+        packagename (str): The name of the package. Used as a subdirectory under the data directory.
+        mcpname (str): The name of the MCP server. Used as a subdirectory under the package directory.
+        env_override (str | None): The name of an environment variable that, if set, overrides the default data directory location. If None, the default location is used.
+
+    Returns:
+        Path: The path to the created data directory for the MCP server.
+    """
+    if env_override:
+        p = os.getenv(env_override)
+        if p:
+            return Path(p)
+    # Use [platformdirs](https://pypi.org/project/platformdirs/) to
+    # choose an appropriate location.
+    d = platformdirs.user_data_dir(appname="seclab-taskflow-agent",
+                                   appauthor="GitHubSecurityLab",
+                                   ensure_exists=True)
+    # Each MCP server gets its own sub-directory
+    p = Path(d).joinpath(packagename).joinpath(mcpname)
+    p.mkdir(parents=True, exist_ok=True)
+    return p