diff --git a/metagpt/actions/write_docstring.py b/metagpt/actions/write_docstring.py
new file mode 100644
index 000000000..091bd0a82
--- /dev/null
+++ b/metagpt/actions/write_docstring.py
@@ -0,0 +1,169 @@
+import ast
+import contextlib
+from typing import Literal
+
+from metagpt.actions.action import Action
+from metagpt.utils.common import OutputParser
+from metagpt.utils.pycst import merge_docstring
+
+PYTHON_DOCSTRING_SYSTEM = '''### Requirements
+1. Add docstrings to the given code following the {style} style.
+2. Remove all private members whose names start with an underscore, such as `_test` and `__init__`.
+3. Replace the function body with an Ellipsis object(...) to reduce output.
+4. If the types are already annotated, there is no need to include them in the docstring.
+5. Only output Python code and avoid including any other text.
+
+### Input Example
+```python
+def function_with_pep484_type_annotations(param1: int) -> bool:
+    return isinstanc(param1, int)
+
+class ExampleError(Exception):
+    def __init__(self, msg: str):
+        self.msg = msg
+```
+
+### Output Example
+```python{example}```
+'''
+
+# https://www.sphinx-doc.org/en/master/usage/extensions/napoleon.html
+
+PYTHON_DOCSTRING_EXAMPLE_GOOGLE = '''
+def function_with_pep484_type_annotations(param1: int) -> bool:
+    """Example function with PEP 484 type annotations.
+
+    Extended description of function.
+
+    Args:
+        param1: The first parameter.
+
+    Returns:
+        The return value. True for success, False otherwise.
+    """
+    ...
+
+class ExampleError(Exception):
+    """Exceptions are documented in the same way as classes.
+
+    The __init__ method was documented in the class level docstring.
+
+    Args:
+        msg: Human readable string describing the exception.
+
+    Attributes:
+        msg: Human readable string describing the exception.
+    """
+    ...
+'''
+
+PYTHON_DOCSTRING_EXAMPLE_NUMPY = '''
+def function_with_pep484_type_annotations(param1: int) -> bool:
+    """
+    Example function with PEP 484 type annotations.
+
+    Extended description of function.
+
+    Parameters
+    ----------
+    param1
+        The first parameter.
+
+    Returns
+    -------
+    bool
+        The return value. True for success, False otherwise.
+    """
+    ...
+
+class ExampleError(Exception):
+    """
+    Exceptions are documented in the same way as classes.
+
+    The __init__ method was documented in the class level docstring.
+
+    Parameters
+    ----------
+    msg
+        Human readable string describing the exception.
+
+    Attributes
+    ----------
+    msg
+        Human readable string describing the exception.
+    """
+    ...
+'''
+
+PYTHON_DOCSTRING_EXAMPLE_SPHINX = '''
+def function_with_pep484_type_annotations(param1: int) -> bool:
+    """Example function with PEP 484 type annotations.
+
+    Extended description of function.
+
+    :param param1: The first parameter.
+    :type param1: int
+
+    :return: The return value. True for success, False otherwise.
+    :rtype: bool
+    """
+    ...
+
+class ExampleError(Exception):
+    """Exceptions are documented in the same way as classes.
+
+    The __init__ method was documented in the class level docstring.
+
+    :param msg: Human-readable string describing the exception.
+    :type msg: str
+    """
+    ...
+'''
+
+_python_docstring_style = {
+    "google": PYTHON_DOCSTRING_EXAMPLE_GOOGLE,
+    "numpy": PYTHON_DOCSTRING_EXAMPLE_NUMPY,
+    "sphinx": PYTHON_DOCSTRING_EXAMPLE_SPHINX,
+}
+
+
+class WriteDocstring(Action):
+
+    def __init__(self, *args, **kwargs):
+        super().__init__(*args, **kwargs)
+        self.desc = "Write docstring for code."
+
+    async def run(
+        self, code: str,
+        system_text: str = PYTHON_DOCSTRING_SYSTEM,
+        style: Literal["google", "numpy", "sphinx"] = "google",
+    ) -> str:
+        system_text = system_text.format(style=style, example=_python_docstring_style[style])
+        simplified_code = _simplify_python_code(code)
+        documented_code = await self._aask(simplified_code, [system_text])
+        with contextlib.suppress(Exception):
+            documented_code = OutputParser.parse_code(documented_code)
+        return merge_docstring(code, documented_code)
+
+
+def _simplify_python_code(code: str) -> None:
+    code_tree = ast.parse(code)
+    code_tree.body = [i for i in code_tree.body if not isinstance(i, ast.Expr)]
+    if isinstance(code_tree.body[-1], ast.If):
+        code_tree.body.pop()
+    return ast.unparse(code_tree)
+
+
+if __name__ == "__main__":
+    import fire
+
+    async def run(filename: str, overwrite: bool = False, style: Literal["google", "numpy", "sphinx"] = "google"):
+        with open(filename) as f:
+            code = f.read()
+        code = await WriteDocstring().run(code, style=style)
+        if overwrite:
+            with open(filename, "w") as f:
+                f.write(code)
+        return code
+
+    fire.Fire(run)
diff --git a/metagpt/utils/pycst.py b/metagpt/utils/pycst.py
new file mode 100644
index 000000000..c2eb532ab
--- /dev/null
+++ b/metagpt/utils/pycst.py
@@ -0,0 +1,169 @@
+from __future__ import annotations
+
+from typing import Union
+
+import libcst as cst
+from libcst._nodes.module import Module
+
+DocstringNode = Union[cst.Module, cst.ClassDef, cst.FunctionDef]
+
+
+def get_docstring_statement(body: DocstringNode) -> cst.SimpleStatementLine:
+    """Extracts the docstring from the body of a node.
+
+    Args:
+        body: The body of a node.
+
+    Returns:
+        The docstring statement if it exists, None otherwise.
+    """
+    if isinstance(body, cst.Module):
+        body = body.body
+    else:
+        body = body.body.body
+
+    if not body:
+        return
+
+    statement = body[0]
+    if not isinstance(statement, cst.SimpleStatementLine):
+        return
+
+    expr = statement
+    while isinstance(expr, (cst.BaseSuite, cst.SimpleStatementLine)):
+        if len(expr.body) == 0:
+            return None
+        expr = expr.body[0]
+
+    if not isinstance(expr, cst.Expr):
+        return None
+    
+    val = expr.value
+    if not isinstance(val, (cst.SimpleString, cst.ConcatenatedString)):
+        return None
+    
+    evaluated_value = val.evaluated_value    
+    if isinstance(evaluated_value, bytes):
+        return None
+
+    return statement
+
+
+class DocstringCollector(cst.CSTVisitor):
+    """A visitor class for collecting docstrings from a CST.
+
+    Attributes:
+        stack: A list to keep track of the current path in the CST.
+        docstrings: A dictionary mapping paths in the CST to their corresponding docstrings.
+    """
+    def __init__(self):
+        self.stack: list[str] = []
+        self.docstrings: dict[tuple[str, ...], cst.SimpleStatementLine] = {}
+
+    def visit_Module(self, node: cst.Module) -> bool | None:
+        self.stack.append("")
+
+    def leave_Module(self, node: cst.Module) -> None:
+        return self._leave(node)
+
+    def visit_ClassDef(self, node: cst.ClassDef) -> bool | None:
+        self.stack.append(node.name.value)
+
+    def leave_ClassDef(self, node: cst.ClassDef) -> None:
+        return self._leave(node)
+
+    def visit_FunctionDef(self, node: cst.FunctionDef) -> bool | None:
+        self.stack.append(node.name.value)
+
+    def leave_FunctionDef(self, node: cst.FunctionDef) -> None:
+        return self._leave(node)
+
+    def _leave(self, node: DocstringNode) -> None:
+        key = tuple(self.stack)
+        self.stack.pop()
+        if hasattr(node, "decorators") and any(i.decorator.value == "overload" for i in node.decorators):
+            return
+
+        statement = get_docstring_statement(node)
+        if statement:
+            self.docstrings[key] = statement
+
+
+class DocstringTransformer(cst.CSTTransformer):
+    """A transformer class for replacing docstrings in a CST.
+
+    Attributes:
+        stack: A list to keep track of the current path in the CST.
+        docstrings: A dictionary mapping paths in the CST to their corresponding docstrings.
+    """
+    def __init__(
+        self,
+        docstrings: dict[tuple[str, ...], cst.SimpleStatementLine],
+    ):
+        self.stack: list[str] = []
+        self.docstrings = docstrings
+
+    def visit_Module(self, node: cst.Module) -> bool | None:
+        self.stack.append("")
+
+    def leave_Module(self, original_node: Module, updated_node: Module) -> Module:
+        return self._leave(original_node, updated_node)
+
+    def visit_ClassDef(self, node: cst.ClassDef) -> bool | None:
+        self.stack.append(node.name.value)
+
+    def leave_ClassDef(self, original_node: cst.ClassDef, updated_node: cst.ClassDef) -> cst.CSTNode:
+        return self._leave(original_node, updated_node)
+
+    def visit_FunctionDef(self, node: cst.FunctionDef) -> bool | None:
+        self.stack.append(node.name.value)
+
+    def leave_FunctionDef(self, original_node: cst.FunctionDef, updated_node: cst.FunctionDef) -> cst.CSTNode:
+        return self._leave(original_node, updated_node)
+
+    def _leave(self, original_node: DocstringNode, updated_node: DocstringNode) -> DocstringNode:
+        key = tuple(self.stack)
+        self.stack.pop()
+
+        if hasattr(updated_node, "decorators") and any((i.decorator.value == "overload") for i in updated_node.decorators):
+            return updated_node
+
+        statement = self.docstrings.get(key)
+        if not statement:
+            return updated_node
+
+        original_statement = get_docstring_statement(original_node)
+
+        if isinstance(updated_node, cst.Module):
+            body = updated_node.body
+            if original_statement:
+                return updated_node.with_changes(body=(body[0], statement, *body[1:]))
+            else:
+                updated_node = updated_node.with_changes(body=(statement, cst.EmptyLine(), *body))
+                return updated_node
+
+        body = updated_node.body.body
+        if original_statement:
+            return updated_node.with_changes(body=updated_node.body.with_changes(body=(body[0], statement, *body[1:])))
+        else:
+            return updated_node.with_changes(body=updated_node.body.with_changes(body=(statement, *body)))
+
+
+def merge_docstring(code: str, documented_code: str) -> str:
+    """Merges the docstrings from the documented code into the original code.
+
+    Args:
+        code: The original code.
+        documented_code: The documented code.
+
+    Returns:
+        The original code with the docstrings from the documented code.
+    """
+    code_tree = cst.parse_module(code)
+    documented_code_tree = cst.parse_module(documented_code)
+
+    visitor = DocstringCollector()
+    documented_code_tree.visit(visitor)
+    transformer = DocstringTransformer(visitor.docstrings)
+    modified_tree = code_tree.visit(transformer)
+    return modified_tree.code
diff --git a/requirements.txt b/requirements.txt
index 32a436962..452e2d092 100644
--- a/requirements.txt
+++ b/requirements.txt
@@ -35,3 +35,4 @@ tqdm==4.64.0
 anthropic==0.3.6
 typing-inspect==0.8.0
 typing_extensions==4.5.0
+libcst==1.0.1
diff --git a/tests/metagpt/actions/test_write_docstring.py b/tests/metagpt/actions/test_write_docstring.py
new file mode 100644
index 000000000..82d96e1a6
--- /dev/null
+++ b/tests/metagpt/actions/test_write_docstring.py
@@ -0,0 +1,32 @@
+import pytest
+
+from metagpt.actions.write_docstring import WriteDocstring
+
+code = '''
+def add_numbers(a: int, b: int):
+    return a + b
+
+
+class Person:
+    def __init__(self, name: str, age: int):
+        self.name = name
+        self.age = age
+
+    def greet(self):
+        return f"Hello, my name is {self.name} and I am {self.age} years old."
+'''
+
+
+@pytest.mark.asyncio
+@pytest.mark.parametrize(
+    ("style", "part"),
+    [
+        ("google", "Args:"),
+        ("numpy", "Parameters"),
+        ("sphinx", ":param name:"),
+    ],
+    ids=["google", "numpy", "sphinx"]
+)
+async def test_write_docstring(style: str, part: str):
+    ret = await WriteDocstring().run(code, style=style)
+    assert part in ret
diff --git a/tests/metagpt/utils/test_pycst.py b/tests/metagpt/utils/test_pycst.py
new file mode 100644
index 000000000..07352eac2
--- /dev/null
+++ b/tests/metagpt/utils/test_pycst.py
@@ -0,0 +1,136 @@
+from metagpt.utils import pycst
+
+code = '''
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+from typing import overload
+
+@overload
+def add_numbers(a: int, b: int):
+    ...
+
+@overload
+def add_numbers(a: float, b: float):
+    ...
+
+def add_numbers(a: int, b: int):
+    return a + b
+
+
+class Person:
+    def __init__(self, name: str, age: int):
+        self.name = name
+        self.age = age
+
+    def greet(self):
+        return f"Hello, my name is {self.name} and I am {self.age} years old."
+'''
+
+documented_code = '''
+"""
+This is an example module containing a function and a class definition.
+"""
+
+
+def add_numbers(a: int, b: int):
+    """This function is used to add two numbers and return the result.
+
+    Parameters:
+        a: The first integer.
+        b: The second integer.
+
+    Returns:
+        int: The sum of the two numbers.
+    """
+    return a + b
+
+class Person:
+    """This class represents a person's information, including name and age.
+
+    Attributes:
+        name: The person's name.
+        age: The person's age.
+    """
+
+    def __init__(self, name: str, age: int):
+        """Creates a new instance of the Person class.
+
+        Parameters:
+            name: The person's name.
+            age: The person's age.
+        """
+        ...
+
+    def greet(self):
+        """
+        Returns a greeting message including the name and age.
+
+        Returns:
+            str: The greeting message.
+        """
+        ...
+'''
+
+
+merged_code = '''
+#!/usr/bin/env python
+# -*- coding: utf-8 -*-
+"""
+This is an example module containing a function and a class definition.
+"""
+
+from typing import overload
+
+@overload
+def add_numbers(a: int, b: int):
+    ...
+
+@overload
+def add_numbers(a: float, b: float):
+    ...
+
+def add_numbers(a: int, b: int):
+    """This function is used to add two numbers and return the result.
+
+    Parameters:
+        a: The first integer.
+        b: The second integer.
+
+    Returns:
+        int: The sum of the two numbers.
+    """
+    return a + b
+
+
+class Person:
+    """This class represents a person's information, including name and age.
+
+    Attributes:
+        name: The person's name.
+        age: The person's age.
+    """
+    def __init__(self, name: str, age: int):
+        """Creates a new instance of the Person class.
+
+        Parameters:
+            name: The person's name.
+            age: The person's age.
+        """
+        self.name = name
+        self.age = age
+
+    def greet(self):
+        """
+        Returns a greeting message including the name and age.
+
+        Returns:
+            str: The greeting message.
+        """
+        return f"Hello, my name is {self.name} and I am {self.age} years old."
+'''
+
+
+def test_merge_docstring():
+    data = pycst.merge_docstring(code, documented_code)
+    print(data)
+    assert data == merged_code