import os
import shutil
from pathlib import Path
from mcp.server.fastmcp import FastMCP
# Initialize FastMCP server
mcp = FastMCP("mcp-file-system")
# Base directory for file operations
BASE_DIR = Path(os.getenv("MCP_FILE_SYSTEM_BASE_DIR", "/tmp/mcp_file_system"))
# Ensure base directory exists
BASE_DIR.mkdir(parents=True, exist_ok=True)
def _resolve_path(file_path: str) -> Path:
"""
Resolves a file path against the base directory and performs security checks.
"""
if ".." in Path(file_path).parts:
raise PermissionError("Path traversal is not allowed.")
# Resolve both paths to absolute paths for comparison
base_dir_abs = BASE_DIR.resolve()
target_path = (BASE_DIR / file_path).resolve()
# Check if the target path is within the base directory
try:
target_path.relative_to(base_dir_abs)
except ValueError:
raise PermissionError("Access denied: Path is outside the allowed base directory.")
return target_path
@mcp.tool()
async def read_file(file_path: str) -> str:
"""
Reads the contents of a file.
Args:
file_path: Path to the file relative to the base directory.
"""
try:
path = _resolve_path(file_path)
if not path.is_file():
return f"Error: '{file_path}' is not a file or does not exist."
return path.read_text(encoding='utf-8')
except Exception as e:
return f"Error reading file '{file_path}': {e}"
@mcp.tool()
async def write_file(file_path: str, content: str) -> str:
"""
Writes content to a file, creating directories if they don't exist and overwriting the file if it does.
Args:
file_path: Path to the file relative to the base directory.
content: The content to write to the file.
"""
try:
path = _resolve_path(file_path)
path.parent.mkdir(parents=True, exist_ok=True)
path.write_text(content, encoding='utf-8')
return f"Successfully wrote {len(content.encode('utf-8'))} bytes to '{file_path}'."
except Exception as e:
return f"Error writing to file '{file_path}': {e}"
@mcp.tool()
async def list_directory(directory_path: str = ".") -> str:
"""
Lists the contents of a directory.
Args:
directory_path: Path to the directory relative to the base directory. Defaults to the base directory itself.
"""
try:
path = _resolve_path(directory_path)
if not path.is_dir():
return f"Error: '{directory_path}' is not a directory."
items = []
for item in sorted(path.iterdir()):
item_type = "DIR" if item.is_dir() else "FILE"
items.append(f"{item_type:4s} {item.name}")
if not items:
# Use a safer way to get the relative path
try:
relative_path = path.relative_to(BASE_DIR.resolve())
except ValueError:
relative_path = str(path)
return f"Directory '{relative_path}' is empty."
# Use a safer way to get the relative path
try:
relative_path = path.relative_to(BASE_DIR.resolve())
except ValueError:
relative_path = str(path)
return f"Contents of '{relative_path}':\n" + "\n".join(items)
except Exception as e:
return f"Error listing directory '{directory_path}': {e}"
@mcp.tool()
async def delete_file(file_path: str) -> str:
"""
Deletes a file. This cannot delete directories.
Args:
file_path: Path to the file to delete, relative to the base directory.
"""
try:
path = _resolve_path(file_path)
if not path.exists():
return f"Error: File '{file_path}' not found."
if not path.is_file():
return f"Error: Path '{file_path}' is a directory, not a file. Use a different tool to delete directories."
path.unlink()
return f"Successfully deleted file '{file_path}'."
except Exception as e:
return f"Error deleting file '{file_path}': {e}"
@mcp.tool()
async def move_file(source_path: str, destination_path: str) -> str:
"""
Moves or renames a file.
Args:
source_path: The path of the file to move.
destination_path: The new path for the file.
"""
try:
source = _resolve_path(source_path)
destination = _resolve_path(destination_path)
if not source.exists():
return f"Error: Source path '{source_path}' does not exist."
destination.parent.mkdir(parents=True, exist_ok=True)
shutil.move(str(source), str(destination))
return f"Successfully moved '{source_path}' to '{destination_path}'."
except Exception as e:
return f"Error moving file: {e}"
@mcp.tool()
async def copy_file(source_path: str, destination_path: str) -> str:
"""
Copies a file.
Args:
source_path: The path of the file to copy.
destination_path: The path to copy the file to.
"""
try:
source = _resolve_path(source_path)
destination = _resolve_path(destination_path)
if not source.is_file():
return f"Error: Source '{source_path}' is not a file."
destination.parent.mkdir(parents=True, exist_ok=True)
shutil.copy2(source, destination)
return f"Successfully copied '{source_path}' to '{destination_path}'."
except Exception as e:
return f"Error copying file: {e}"
if __name__ == "__main__":
mcp.run(transport='stdio')
