diff --git a/csst_common/__init__.py b/csst_common/__init__.py
index bd486b377ec32762c2b1cae0b2f3e1d9c29a1e6e..f0f48ca7afa1da32687cf12040746a951312b62a 100644
--- a/csst_common/__init__.py
+++ b/csst_common/__init__.py
@@ -10,11 +10,11 @@ Modified-History:
     2023-12-15, Bo Zhang, add module header
 """
 
-from .ccds import CCDS
 from .decorator import parameterized_module_decorator
-from .dfs import DFS
 from .file import File
 from .pipeline import Pipeline
 from .status import CsstResult, CsstStatus
 
 __version__ = "0.0.2"
+
+__all__ = ["Pipeline", "File", "CsstResult"]
diff --git a/csst_common/file.py b/csst_common/file.py
index 25136ba384af2cbff247bec33085de5b4e1b988c..5fa0e5623c359f78b48719dbfe1687f41987cb1f 100644
--- a/csst_common/file.py
+++ b/csst_common/file.py
@@ -16,7 +16,22 @@ from typing import Optional
 
 
 class File:
-    def __init__(self, file_path: str = "/path/to/file.fits", new_dir=None):
+    """
+    CSST MSC standard file path parser.
+
+    It can be used for parse CSST MSC file paths and generate corresponding output file paths.
+
+    Parameters
+    ----------
+    file_path : str
+        File path.
+    new_dir : str
+        New directory.
+    """
+
+    def __init__(
+        self, file_path: str = "/path/to/file.fits", new_dir: Optional[str] = None
+    ):
         self.file_path = file_path
         # get dir name
         self.dirname = os.path.dirname(self.file_path)
diff --git a/csst_common/pipeline.py b/csst_common/pipeline.py
index 94a3e05f5efc10f3e9befa7af7fa192c77305270..f6440f036f13c83dad8eb320bf316b1458203740 100644
--- a/csst_common/pipeline.py
+++ b/csst_common/pipeline.py
@@ -25,6 +25,35 @@ from .logger import get_logger
 
 
 class Pipeline:
+    """
+    CSST pipeline configuration class.
+
+    It should be used for every pipeline to initialize environment.
+
+    Parameters
+    ----------
+    dir_input : str
+        Input path.
+    dir_output : str
+        Output path.
+    dir_aux : str
+        Aux path.
+    dfs_root : str
+        DFS root path.
+    ccds_root : str
+        CCDS root path.
+    ccds_cache : str
+        CCDS cache path.
+    filter_warnings : bool
+        If `True`, filter warnings.
+    dfs : bool
+        If `True`, initialize DFS.
+    ccds : bool
+        If `True`, initialize CCDS.
+    **kwargs : Any
+        Additional keyword arguments.
+    """
+
     def __init__(
         self,
         dir_input: str = "/pipeline/input",
diff --git a/csst_common/status.py b/csst_common/status.py
index 0b0980c56b2ed754a3864331896ab8b11c4789f5..9f8c6b71144b028abc8b3c777799a39911939a16 100644
--- a/csst_common/status.py
+++ b/csst_common/status.py
@@ -15,10 +15,10 @@ from typing import Optional, Any
 
 class CsstStatus(IntEnum):
     """
-    The CSST Status class.
+    The CSST standard status class.
 
-    This class provides a set of status which should be returned
-    from each CSST L1 functional module.
+    This class provides a set of status which should be returned from each CSST algorithm module.
+    0, 1, 2 stands for PERFECT, WARNING, ERROR, respectively.
 
     Examples
     --------
@@ -36,6 +36,19 @@ class CsstStatus(IntEnum):
 
 class CsstResult:
     """
+    CSST standard result class.
+
+    This is designed for all algorithm modules.
+
+    Parameters
+    ----------
+    status : CsstStatus
+        The final status of the algorithm.
+    files : Optional[list[str]]
+        The files to which changes are made.
+    **output : Any
+        Additional results.
+
     Examples
     --------
     >>> CsstResult(CsstStatus.PERFECT, ["file1.fits", "file2.fits"])