diff --git a/metagpt/utils/tree.py b/metagpt/utils/tree.py
index 49b5634c6..ad3373f5f 100644
--- a/metagpt/utils/tree.py
+++ b/metagpt/utils/tree.py
@@ -6,94 +6,166 @@
 @File    : tree.py
 @Desc    : Implement the same functionality as the `tree` command.
 Example:
-        root
-        +-- dir1
-        |   +-- file1.txt
-        |   +-- file2.txt
-        +-- dir2
-        |   +-- subdir1
-        |   |   +-- file1.txt
-        |   |   +-- file2.txt
-        |   +-- subdir2
-        |       +-- file1.txt
-        |       +-- file2.txt
-        +-- file.txt
+        Usage:
+            >>> print_tree(".")
+            utils
+            +-- serialize.py
+            +-- project_repo.py
+            +-- tree.py
+            +-- mmdc_playwright.py
+            +-- dependency_file.py
+            +-- index.html
+            +-- make_sk_kernel.py
+            +-- token_counter.py
+            +-- embedding.py
+            +-- repair_llm_raw_output.py
+            +-- mermaid.py
+            +-- parse_html.py
+            +-- visual_graph_repo.py
+            +-- special_tokens.py
+            +-- ahttp_client.py
+            +-- __init__.py
+            +-- mmdc_ink.py
+            +-- di_graph_repository.py
+            +-- yaml_model.py
+            +-- cost_manager.py
+            +-- __pycache__
+            |   +-- __init__.cpython-39.pyc
+            |   +-- redis.cpython-39.pyc
+            |   +-- singleton.cpython-39.pyc
+            |   +-- mmdc_ink.cpython-39.pyc
+            |   +-- read_document.cpython-39.pyc
+            |   +-- mermaid.cpython-39.pyc
+            |   +-- parse_html.cpython-39.pyc
+            |   +-- human_interaction.cpython-39.pyc
+            |   +-- cost_manager.cpython-39.pyc
+            |   +-- json_to_markdown.cpython-39.pyc
+            |   +-- graph_repository.cpython-39.pyc
+            |   +-- ahttp_client.cpython-39.pyc
+            |   +-- visual_graph_repo.cpython-39.pyc
+            |   +-- file.cpython-39.pyc
+            |   +-- di_graph_repository.cpython-39.pyc
+            |   +-- pycst.cpython-39.pyc
+            |   +-- save_code.cpython-39.pyc
+            |   +-- dependency_file.cpython-39.pyc
+            |   +-- text.cpython-39.pyc
+            |   +-- token_counter.cpython-39.pyc
+            |   +-- project_repo.cpython-39.pyc
+            |   +-- yaml_model.cpython-39.pyc
+            |   +-- serialize.cpython-39.pyc
+            |   +-- git_repository.cpython-39.pyc
+            |   +-- custom_decoder.cpython-39.pyc
+            |   +-- parse_docstring.cpython-39.pyc
+            |   +-- common.cpython-39.pyc
+            |   +-- exceptions.cpython-39.pyc
+            |   +-- repair_llm_raw_output.cpython-39.pyc
+            |   +-- s3.cpython-39.pyc
+            |   +-- embedding.cpython-39.pyc
+            |   +-- make_sk_kernel.cpython-39.pyc
+            |   +-- file_repository.cpython-39.pyc
+            +-- file.py
+            +-- save_code.py
+            +-- common.py
+            +-- redis.py
+            +-- text.py
+            +-- graph_repository.py
+            +-- singleton.py
+            +-- recovery_util.py
+            +-- file_repository.py
+            +-- pycst.py
+            +-- exceptions.py
+            +-- human_interaction.py
+            +-- highlight.py
+            +-- mmdc_pyppeteer.py
+            +-- s3.py
+            +-- json_to_markdown.py
+            +-- custom_decoder.py
+            +-- git_repository.py
+            +-- read_document.py
+            +-- parse_docstring.py
 """
 from __future__ import annotations
 
 from pathlib import Path
 from typing import Callable, Dict, List
 
-from anthropic import BaseModel
-from pydantic import Field
 
-
-class Tree(BaseModel):
+def tree(root: str | Path, git_ignore_rules: Callable = None) -> str:
     """
-    Represents a directory tree structure.
+    Recursively traverses the directory structure and prints it out in a tree-like format.
 
-    Attributes:
-        root (str): The root directory of the tree.
-        tree (Dict[str, Dict]): The tree structure as a dictionary.
+    Args:
+        root (str or Path): The root directory from which to start traversing.
+        git_ignore_rules (Callable): Optional. A function to filter files to ignore.
 
-    Methods:
-        print: Print the directory tree structure.
+    Returns:
+        str: A string representation of the directory tree.
+
+    Example:
+            >>> tree(".")
+            utils
+            +-- serialize.py
+            +-- project_repo.py
+            +-- tree.py
+            +-- mmdc_playwright.py
+            +-- __pycache__
+            |   +-- __init__.cpython-39.pyc
+            |   +-- redis.cpython-39.pyc
+            |   +-- singleton.cpython-39.pyc
+            +-- parse_docstring.py
+
+            >>> from gitignore_parser import parse_gitignore
+            >>> tree(".", git_ignore_rules=parse_gitignore(full_path="../../.gitignore"))
+            utils
+            +-- serialize.py
+            +-- project_repo.py
+            +-- tree.py
+            +-- mmdc_playwright.py
+            +-- parse_docstring.py
 
     """
+    root = Path(root).resolve()
+    dir_ = {root.name: _list_children(root=root, git_ignore_rules=git_ignore_rules)}
+    v = _print_tree(dir_)
+    return "\n".join(v)
 
-    root: str
-    tree: Dict[str, Dict] = Field(default_factory=dict)
 
-    def print(self, git_ignore_rules: Callable = None) -> str:
-        """
-        Recursively traverses the directory structure and prints it out in a tree-like format.
-
-        Args:
-            git_ignore_rules (Callable): Optional. A function to filter files to ignore.
-
-        Returns:
-            str: A string representation of the directory tree.
-
-        """
-        root = Path(self.root).resolve()
-        self.tree[root.name] = self._list_children(root=root, git_ignore_rules=git_ignore_rules)
-        v = self._print_tree(self.tree)
-        return "\n".join(v)
-
-    @staticmethod
-    def _list_children(root: Path, git_ignore_rules: Callable) -> Dict[str, Dict]:
-        tree = {}
-        for i in root.iterdir():
-            if git_ignore_rules and git_ignore_rules(str(i)):
-                continue
+def _list_children(root: Path, git_ignore_rules: Callable) -> Dict[str, Dict]:
+    dir_ = {}
+    for i in root.iterdir():
+        if git_ignore_rules and git_ignore_rules(str(i)):
+            continue
+        try:
             if i.is_file():
-                tree[i.name] = {}
+                dir_[i.name] = {}
             else:
-                tree[i.name] = Tree._list_children(root=i, git_ignore_rules=git_ignore_rules)
-        return tree
+                dir_[i.name] = _list_children(root=i, git_ignore_rules=git_ignore_rules)
+        except (FileNotFoundError, PermissionError, OSError):
+            dir_[i.name] = {}
+    return dir_
 
-    @staticmethod
-    def _print_tree(tree: Dict[str:Dict], indent: int = 0) -> List[str]:
-        ret = []
-        for name, children in tree.items():
-            ret.append(name)
-            if not children:
-                continue
-            lines = Tree._print_tree(tree=children, indent=indent + 1)
-            for j, v in enumerate(lines):
-                if v[0] not in ["+", " ", "|"]:
-                    ret = Tree._add_line(ret)
-                    row = f"+-- {v}"
-                else:
-                    row = f"    {v}"
-                ret.append(row)
-        return ret
 
-    @staticmethod
-    def _add_line(rows: List[str]) -> List[str]:
-        for i in range(len(rows) - 1, -1, -1):
-            v = rows[i]
-            if v[0] != " ":
-                return rows
-            rows[i] = "|" + v[1:]
-        return rows
+def _print_tree(dir_: Dict[str:Dict]) -> List[str]:
+    ret = []
+    for name, children in dir_.items():
+        ret.append(name)
+        if not children:
+            continue
+        lines = _print_tree(children)
+        for j, v in enumerate(lines):
+            if v[0] not in ["+", " ", "|"]:
+                ret = _add_line(ret)
+                row = f"+-- {v}"
+            else:
+                row = f"    {v}"
+            ret.append(row)
+    return ret
+
+
+def _add_line(rows: List[str]) -> List[str]:
+    for i in range(len(rows) - 1, -1, -1):
+        v = rows[i]
+        if v[0] != " ":
+            return rows
+        rows[i] = "|" + v[1:]
+    return rows
diff --git a/tests/metagpt/utils/test_tree.py b/tests/metagpt/utils/test_tree.py
index 0d48f7ce3..34eae10cf 100644
--- a/tests/metagpt/utils/test_tree.py
+++ b/tests/metagpt/utils/test_tree.py
@@ -4,7 +4,7 @@ from typing import List
 import pytest
 from gitignore_parser import parse_gitignore
 
-from metagpt.utils.tree import Tree
+from metagpt.utils.tree import _print_tree, tree
 
 
 @pytest.mark.parametrize(
@@ -16,8 +16,8 @@ from metagpt.utils.tree import Tree
 )
 def test_tree(root: str, rules: str):
     gitignore_rules = parse_gitignore(full_path=rules) if rules else None
-    tree = Tree(root=root).print(git_ignore_rules=gitignore_rules)
-    assert tree
+    v = tree(root=root, git_ignore_rules=gitignore_rules)
+    assert v
 
 
 @pytest.mark.parametrize(
@@ -46,7 +46,7 @@ def test_tree(root: str, rules: str):
     ],
 )
 def test__print_tree(tree: dict, want: List[str]):
-    v = Tree._print_tree(tree)
+    v = _print_tree(tree)
     assert v == want