diff --git a/pyproject.toml b/pyproject.toml
index 4699ba9..dcfb2a4 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -5,7 +5,6 @@ description = "Add your description here"
 readme = "README.md"
 requires-python = ">=3.12"
 dependencies = [
-    "pydantic-settings~=2.12",
     "pynvim~=0.6.0",
     "requests>=2.32.5",
 ]
diff --git a/rplugin/python3/mrpy/clickup.py b/rplugin/python3/mrpy/clickup.py
index 00be9a5..a60a4f3 100644
--- a/rplugin/python3/mrpy/clickup.py
+++ b/rplugin/python3/mrpy/clickup.py
@@ -1,8 +1,9 @@
+from dataclasses import dataclass, field
 from json import loads
-from typing import Any
+from os import environ
+from typing import Any, Callable
 
 from pydantic import AliasPath, BaseModel, Field, field_validator
-from pydantic_settings import BaseSettings
 
 from urllib.request import Request, urlopen
 
@@ -105,10 +106,15 @@ class ClickupTask(BaseModel):
         return ret
 
 
-class ClickupSession(BaseSettings):
-    auth_key: str = Field(alias="CLICKUP_AUTH", default=...)
-    workspace_id: str = Field(alias="CLICKUP_WORKSPACE_ID", default=...)
-    user_id: str = Field(alias="CLICKUP_USER_ID", default=...)
+def get_env_var(var_name: str) -> Callable[[], str]:
+    return lambda var=var_name: environ[var]
+
+
+@dataclass
+class ClickupSession:
+    auth_key: str = field(default_factory=get_env_var("CLICKUP_AUTH"))
+    workspace_id: str = field(default_factory=get_env_var("CLICKUP_WORKSPACE_ID"))
+    user_id: str = field(default_factory=get_env_var("CLICKUP_USER_ID"))
     base_url: str = "https://api.clickup.com/api/v2"
 
     def _get(self, endpoint: str, **query_params: Any) -> dict[str, Any]: