Filesystem MCP Server

Node.js server implementing Model Context Protocol (MCP) for filesystem operations with comprehensive permission controls and enhanced functionality.

Features

• Granular permission controls (read-only, full access, or specific operation permissions)
• Secure file operations within allowed directories
• File operations:
  • Read/write/modify files
  • Create/list/delete directories
  • Move files/directories
  • Search files by name or extension
  • Get file metadata
• Directory operations:
  • Tree view of directory structures
  • Recursive operations with exclusion patterns
• Utility functions:
  • XML to JSON conversion
  • Multiple file operations in one call
  • Advanced file editing with pattern matching
• Security features:
  • Symlink control
  • Path validation
  • Sandboxed operations

Note: The server will only allow operations within directories specified via args and according to the configured permissions.

API

Resources

• file://system: File system operations interface

Tools

• read_file

  • Read complete contents of a file
  • Input: path (string)
  • Reads complete file contents with UTF-8 encoding

• read_multiple_files

  • Read multiple files simultaneously
  • Input: paths (string[])
  • Failed reads won't stop the entire operation

• create_file

  • Create a new file with content
  • Inputs:
    • path (string): File location
    • content (string): File content
  • Fails if file already exists
  • Requires create permission

• modify_file

  • Modify an existing file with new content
  • Inputs:
    • path (string): File location
    • content (string): New file content
  • Fails if file doesn't exist
  • Requires edit permission

• edit_file

  • Make selective edits using pattern matching and formatting
  • Features:
    • Line-based and multi-line content matching
    • Whitespace normalization with indentation preservation
    • Multiple simultaneous edits with correct positioning
    • Indentation style detection and preservation
    • Git-style diff output with context
    • Preview changes with dry run mode
  • Inputs:
    • path (string): File to edit
    • edits (array): List of edit operations
      • oldText (string): Text to search for (exact match)
      • newText (string): Text to replace with
    • dryRun (boolean): Preview changes without applying (default: false)
  • Returns detailed diff for dry runs, otherwise applies changes
  • Requires edit permission
  • Best Practice: Always use dryRun first to preview changes

• create_directory

  • Create new directory or ensure it exists
  • Input: path (string)
  • Creates parent directories if needed
  • Succeeds silently if directory exists
  • Requires create permission

• list_directory

  • List directory contents with [FILE] or [DIR] prefixes
  • Input: path (string)
  • Returns detailed listing of files and directories

• directory_tree

  • Get recursive tree view of directory structure
  • Input: path (string)
  • Returns JSON structure with files and directories
  • Each entry includes name, type, and children (for directories)

• move_file

  • Move or rename files and directories
  • Inputs:
    • source (string): Source path
    • destination (string): Destination path
  • Fails if destination exists
  • Works for both files and directories
  • Requires move permission

• delete_file

  • Delete a file
  • Input: path (string)
  • Fails if file doesn't exist
  • Requires delete permission

• delete_directory

  • Delete a directory
  • Inputs:
    • path (string): Directory to delete
    • recursive (boolean): Whether to delete contents (default: false)
  • Fails if directory is not empty and recursive is false
  • Requires delete permission

• search_files

  • Recursively search for files/directories
  • Inputs:
    • path (string): Starting directory
    • pattern (string): Search pattern
    • excludePatterns (string[]): Exclude patterns (glob format supported)
  • Case-insensitive matching
  • Returns full paths to matches

• find_files_by_extension

  • Find all files with specific extension
  • Inputs:
    • path (string): Starting directory
    • extension (string): File extension to find
    • excludePatterns (string[]): Optional exclude patterns
  • Case-insensitive extension matching
  • Returns full paths to matching files

• get_file_info

  • Get detailed file/directory metadata
  • Input: path (string)
  • Returns:
    • Size
    • Creation time
    • Modified time
    • Access time
    • Type (file/directory)
    • Permissions

• get_permissions

  • Get current server permissions
  • No input required
  • Returns:
    • Permission flags (readonly, fullAccess, create, edit, move, delete)
    • Symlink following status
    • Number of allowed directories

• list_allowed_directories

  • List all directories the server is allowed to access
  • No input required
  • Returns array of allowed directory paths

• xml_to_json

  • Convert XML file to JSON format
  • Inputs:
    • xmlPath (string): Source XML file
    • jsonPath (string): Destination JSON file
    • options (object): Optional settings
      • ignoreAttributes (boolean): Skip XML attributes (default: false)
      • preserveOrder (boolean): Maintain property order (default: true)
      • format (boolean): Pretty print JSON (default: true)
      • indentSize (number): JSON indentation (default: 2)
  • Requires read permission for XML file
  • Requires create or edit permission for JSON file

• xml_to_json_string

  • Convert XML file to JSON string
  • Inputs:
    • xmlPath (string): Source XML file
    • options (object): Optional settings
      • ignoreAttributes (boolean): Skip XML attributes (default: false)
      • preserveOrder (boolean): Maintain property order (default: true)
  • Requires read permission for XML file
  • Returns JSON string representation

• xml_query

  • Query XML file using XPath expressions
  • Inputs:
    • path (string): Path to the XML file
    • query (string, optional): XPath query to execute
    • structureOnly (boolean, optional): Return only tag structure
    • maxBytes (number, optional): Maximum bytes to read (default: 1MB)
    • includeAttributes (boolean, optional): Include attribute info (default: true)
  • XPath examples:
    • Get all elements: //tagname
    • Get elements with specific attribute: //tagname[@attr="value"]
    • Get text content: //tagname/text()
  • Memory efficient for large XML files
  • Returns JSON representation of query results or structure

• xml_structure

  • Analyze XML structure without reading entire file
  • Inputs:
    • path (string): Path to the XML file
    • depth (number, optional): How deep to analyze (default: 2)
    • includeAttributes (boolean, optional): Include attribute analysis
    • maxBytes (number, optional): Maximum bytes to read (default: 1MB)
  • Returns statistical information about elements, attributes, and structure
  • Useful for understanding large XML files before detailed analysis

Permissions & Security

The server implements a comprehensive security model with granular permission controls:

Directory Access Control

• Operations are strictly limited to directories specified during startup via args
• All operations (including symlink targets) must remain within allowed directories
• Path validation ensures no directory traversal or access outside allowed paths

Permission Flags

• --readonly: Enforces read-only mode, overriding all other permission flags
• --full-access: Enables all operations (create, edit, move, delete)
• Individual permission flags (require explicit enabling unless --full-access is set):
  • --allow-create: Allow creation of new files and directories
  • --allow-edit: Allow modification of existing files
  • --allow-move: Allow moving/renaming files and directories
  • --allow-delete: Allow deletion of files and directories

Default Behavior: If no permission flags are specified, the server runs in read-only mode. To enable any write operations, you must use either --full-access or specific --allow-* flags.

Symlink Handling

• By default, symlinks are followed (both link and target must be in allowed directories)
• --no-follow-symlinks: Disable symlink following (operations act on the link itself)

Usage with Claude Desktop and Cursor

Add appropriate configuration to either claude_desktop_config.json (for Claude Desktop) or .cursor/mcp.json (for Cursor):

Cursor Configuration

In .cursor/mcp.json:

{
  "mcpServers": {
    "my-filesystem": {
      "command": "node",
      "args": [
        "/path/to/mcp-filesystem/dist/index.js",
        "~/path/to/allowed/directory",
        "--full-access"
      ]
    }
  }
}

Docker Configuration

For Claude Desktop with Docker:

{
  "mcpServers": {
    "filesystem": {
      "command": "docker",
      "args": [
        "run",
        "-i",
        "--rm",
        "--mount", "type=bind,src=/Users/username/Desktop,dst=/projects/Desktop",
        "--mount", "type=bind,src=/path/to/other/allowed/dir,dst=/projects/other/allowed/dir,ro",
        "--mount", "type=bind,src=/path/to/file.txt,dst=/projects/path/to/file.txt",
        "mcp/filesystem",
        "--readonly",                    // For read-only access
        "--no-follow-symlinks",         // Optional: prevent symlink following
        "/projects"
      ]
    }
  }
}

NPX Configuration

For either Claude Desktop or Cursor with NPX:

{
  "mcpServers": {
    "filesystem": {
      "command": "npx",
      "args": [
        "-y",
        "@modelcontextprotocol/server-filesystem",
        "--full-access",                // For full read/write access
        "/Users/username/Desktop",
        "/path/to/other/allowed/dir"
      ]
    }
  }
}

Permission Flag Examples

You can configure the server with various permission combinations:

"args": [
  "/path/to/mcp-filesystem/dist/index.js",
  "~/path/to/allowed/directory",
  "--readonly"                         // Read-only mode
]

"args": [
  "/path/to/mcp-filesystem/dist/index.js",
  "~/path/to/allowed/directory",
  "--full-access",                    // Full read/write access
  "--no-follow-symlinks"              // Don't follow symlinks
]

"args": [
  "/path/to/mcp-filesystem/dist/index.js",
  "~/path/to/allowed/directory",
  "--allow-create",                   // Selective permissions
  "--allow-edit"                      // Only allow creation and editing
]

Note: --readonly takes precedence over all other permission flags, and --full-access enables all operations unless --readonly is specified.

Multiple Directories and Permissions

When specifying multiple directories, permission flags apply globally to all directories:

"args": [
  "/path/to/mcp-filesystem/dist/index.js",
  "~/first/directory",                // Both directories have the same
  "~/second/directory",               // permission settings (read-only)
  "--readonly"
]

If you need different permission levels for different directories, create multiple server configurations:

{
  "mcpServers": {
    "readonly-filesystem": {
      "command": "node",
      "args": [
        "/path/to/mcp-filesystem/dist/index.js",
        "~/sensitive/directory",
        "--readonly"
      ]
    },
    "writeable-filesystem": {
      "command": "node",
      "args": [
        "/path/to/mcp-filesystem/dist/index.js",
        "~/sandbox/directory",
        "--full-access"
      ]
    }
  }
}

Command Line Examples

1. Read-only access:

npx -y @modelcontextprotocol/server-filesystem --readonly /path/to/dir

2. Full access:

npx -y @modelcontextprotocol/server-filesystem --full-access /path/to/dir

3. Specific permissions:

npx -y @modelcontextprotocol/server-filesystem --allow-create --allow-edit /path/to/dir

4. No symlink following:

npx -y @modelcontextprotocol/server-filesystem --full-access --no-follow-symlinks /path/to/dir

Build

Docker build:

docker build -t mcp/filesystem -f src/filesystem/Dockerfile .

License

This MCP server is licensed under the MIT License. This means you are free to use, modify, and distribute the software, subject to the terms and conditions of the MIT License. For more details, please see the LICENSE file in the project repository.