diff --git a/docs/Makefile b/docs/Makefile
new file mode 100644
index 0000000..d0c3cbf
--- /dev/null
+++ b/docs/Makefile
@@ -0,0 +1,20 @@
+# Minimal makefile for Sphinx documentation
+#
+
+# You can set these variables from the command line, and also
+# from the environment for the first two.
+SPHINXOPTS    ?=
+SPHINXBUILD   ?= sphinx-build
+SOURCEDIR     = source
+BUILDDIR      = build
+
+# Put it first so that "make" without argument is like "make help".
+help:
+	@$(SPHINXBUILD) -M help "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
+
+.PHONY: help Makefile
+
+# Catch-all target: route all unknown targets to Sphinx using the new
+# "make mode" option.  $(O) is meant as a shortcut for $(SPHINXOPTS).
+%: Makefile
+	@$(SPHINXBUILD) -M $@ "$(SOURCEDIR)" "$(BUILDDIR)" $(SPHINXOPTS) $(O)
diff --git a/docs/make.bat b/docs/make.bat
new file mode 100644
index 0000000..747ffb7
--- /dev/null
+++ b/docs/make.bat
@@ -0,0 +1,35 @@
+@ECHO OFF
+
+pushd %~dp0
+
+REM Command file for Sphinx documentation
+
+if "%SPHINXBUILD%" == "" (
+	set SPHINXBUILD=sphinx-build
+)
+set SOURCEDIR=source
+set BUILDDIR=build
+
+%SPHINXBUILD% >NUL 2>NUL
+if errorlevel 9009 (
+	echo.
+	echo.The 'sphinx-build' command was not found. Make sure you have Sphinx
+	echo.installed, then set the SPHINXBUILD environment variable to point
+	echo.to the full path of the 'sphinx-build' executable. Alternatively you
+	echo.may add the Sphinx directory to PATH.
+	echo.
+	echo.If you don't have Sphinx installed, grab it from
+	echo.https://www.sphinx-doc.org/
+	exit /b 1
+)
+
+if "%1" == "" goto help
+
+%SPHINXBUILD% -M %1 %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+goto end
+
+:help
+%SPHINXBUILD% -M help %SOURCEDIR% %BUILDDIR% %SPHINXOPTS% %O%
+
+:end
+popd
diff --git a/docs/source/conf.py b/docs/source/conf.py
new file mode 100644
index 0000000..5e3990d
--- /dev/null
+++ b/docs/source/conf.py
@@ -0,0 +1,26 @@
+# Configuration file for the Sphinx documentation builder.
+#
+# For the full list of built-in configuration values, see the documentation:
+# https://www.sphinx-doc.org/en/master/usage/configuration.html
+
+# -- Project information -----------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#project-information
+
+project = "polymind"
+copyright = "2024, TechTao"
+author = "TechTao"
+
+# -- General configuration ---------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#general-configuration
+
+extensions = []
+
+templates_path = ["_templates"]
+exclude_patterns = []
+
+
+# -- Options for HTML output -------------------------------------------------
+# https://www.sphinx-doc.org/en/master/usage/configuration.html#options-for-html-output
+
+html_theme = "alabaster"
+html_static_path = ["_static"]
diff --git a/docs/source/index.rst b/docs/source/index.rst
new file mode 100644
index 0000000..791e908
--- /dev/null
+++ b/docs/source/index.rst
@@ -0,0 +1,20 @@
+.. polymind documentation master file, created by
+   sphinx-quickstart on Tue Mar 19 21:51:36 2024.
+   You can adapt this file completely to your liking, but it should at least
+   contain the root `toctree` directive.
+
+Welcome to polymind's documentation!
+====================================
+
+.. toctree::
+   :maxdepth: 2
+   :caption: Contents:
+
+
+
+Indices and tables
+==================
+
+* :ref:`genindex`
+* :ref:`modindex`
+* :ref:`search`
diff --git a/polymind/core/tool.py b/polymind/core/tool.py
index 14bc0dd..57d077f 100644
--- a/polymind/core/tool.py
+++ b/polymind/core/tool.py
@@ -33,7 +33,16 @@ def __str__(self) -> str:
     @field_validator("type")
     def check_type(cls, v: str) -> str:
         allowed_simple_types = [
-            "str", "int", "float", "bool", "ndarray", "np.ndarray", "pandas.DataFrame", "pd.DataFrame"
+            "str",
+            "int",
+            "float",
+            "bool",
+            "ndarray",
+            "np.ndarray",
+            "numpy.ndarray",
+            "pandas.DataFrame",
+            "pd.DataFrame",
+            "DataFrame",
         ]
         if v in allowed_simple_types:
             return v
diff --git a/pyproject.toml b/pyproject.toml
index 4f165b5..22c4365 100644
--- a/pyproject.toml
+++ b/pyproject.toml
@@ -1,6 +1,6 @@
 [tool.poetry]
 name = "polymind"
-version = "0.0.21"  # Update this version before publishing to PyPI
+version = "0.0.22"  # Update this version before publishing to PyPI
 description = "PolyMind is a customizable collaborative multi-agent framework for collective intelligence and distributed problem solving."
 authors = ["TechTao"]
 license = "MIT License"
diff --git a/tests/polymind/core/test_tool.py b/tests/polymind/core/test_tool.py
index 348d89d..778abbf 100644
--- a/tests/polymind/core/test_tool.py
+++ b/tests/polymind/core/test_tool.py
@@ -14,7 +14,21 @@
 
 
 class TestParam:
-    @pytest.mark.parametrize("type_str", ["str", "int", "float"])
+    @pytest.mark.parametrize(
+        "type_str",
+        [
+            "str",
+            "int",
+            "float",
+            "bool",
+            "ndarray",
+            "np.ndarray",
+            "numpy.ndarray",
+            "DataFrame",
+            "pd.DataFrame",
+            "pandas.DataFrame",
+        ],
+    )
     def test_valid_simple_types(self, type_str):
         """Test that Param accepts valid simple type strings."""
         param = Param(
@@ -32,6 +46,10 @@ def test_valid_simple_types(self, type_str):
             ("Dict[str, int]", "{'key': 123}"),
             ("List[int]", "[1, 2, 3]"),
             ("np.ndarray", "np.array([1, 2, 3])"),
+            (
+                "pd.DataFrame",
+                "pd.DataFrame({'col1': [1, 2, 3], 'col2': ['a', 'b', 'c']})",
+            ),
         ],
     )
     def test_valid_complex_types_with_example(self, type_str, example):