LocalFiles MCP Server

A Model Context Protocol (MCP) server that provides secure access to local files from specified directories.

Features

• List files in configured directories

• Read file contents (text and binary)

• File size and extension filtering

• Secure path validation

• Configuration via .env file or environment variables

Configuration

Method 1: .env file (Recommended)

Create a .env file in the same directory as app.py:

# Comma-separated list of allowed directories
ALLOWED_DIRECTORIES=/home/user/documents,/home/user/projects,/path/to/your/files

# Maximum file size in bytes (default: 10MB)
MAX_FILE_SIZE=10485760

# Allowed file extensions (comma-separated)
ALLOWED_EXTENSIONS=.txt,.md,.py,.js,.json,.yaml,.yml,.csv,.xml,.html,.css

Method 2: Environment Variables

Set environment variables directly:

export ALLOWED_DIRECTORIES="/home/user/documents,/home/user/projects"
export MAX_FILE_SIZE=10485760
export ALLOWED_EXTENSIONS=".txt,.md,.py,.js,.json,.yaml,.yml,.csv,.xml,.html,.css"

Usage

Start the server

python app.py

Available Tools

1. lf_list_files - List files in allowed directories

2. lf_read_file - Read contents of a specific file

3. lf_get_config - Get current server configuration

Security

• Only files within configured ALLOWED_DIRECTORIES can be accessed

• File size limits prevent reading overly large files

• File extension filtering restricts access to specified file types

• All paths are resolved and validated to prevent directory traversal attacks

Troubleshooting

"No allowed directories configured" error

This error occurs when:

1. No .env file exists - Create a .env file with ALLOWED_DIRECTORIES setting

2. Empty ALLOWED_DIRECTORIES - Ensure the value is not empty

3. Wrong working directory - The server looks for .env in the script directory first, then current directory

4. Environment variables not set - If not using .env, ensure environment variables are properly set

Debug configuration

Use the lf_get_config tool to check what configuration the server is actually using:

# This will show the current configuration
lf_get_config()

Example .env file

# Example configuration for a development environment
ALLOWED_DIRECTORIES=/home/alice/projects,/home/alice/documents,/tmp/safe-files
MAX_FILE_SIZE=52428800
ALLOWED_EXTENSIONS=.txt,.md,.py,.js,.json,.yaml,.yml,.csv,.xml,.html,.css,.log

Requirements

• Python 3.7+

• fastmcp library

• pathlib (built-in)

Installation

pip install fastmcp