Windows CLI MCP Server (Enhanced)

MCP server for secure command-line interactions on Windows systems, enabling controlled access to PowerShell, CMD, Git Bash, and Bash shells. It allows MCP clients (like Claude Desktop) to perform operations on your system, similar to Open Interpreter.

This enhanced version includes advanced configuration management, improved security features, and comprehensive testing capabilities.

• Windows CLI MCP Server (Enhanced)

  • Features

  • Usage with Claude Desktop

    • Configuration Setup

  • Configuration

    • Configuration Structure

    • Configuration Locations

    • Default Configuration

    • Configuration Settings

      • Global Settings

        • Security Settings

        • Restriction Settings

        • Path Settings

      • Shell Configuration

        • Basic Shell Configuration

        • Shell-Specific Overrides

        • WSL Configuration

    • Configuration Inheritance

  • API

    • Tools

    • Resources

  • Security Considerations

    • Built-in Security Features

    • Configurable Security Features (Active by Default)

    • Best Practices

  • Using the MCP Inspector for Testing

  • Development and Testing

    • Running Tests

    • Cross-Platform Testing

  • Acknowledgments

  • Development Environment using Dev Containers

    • Prerequisites

    • Getting Started

    • Running Tests in the Dev Container

  • License

Features

• Multi-Shell Support: Execute commands in PowerShell, Command Prompt (CMD), Git Bash, Bash, and WSL

• Modular Architecture: Build only the shells you need for smaller bundle sizes (30-65% reduction)

• Inheritance-Based Configuration: Global defaults with shell-specific overrides

• Shell-Specific Validation: Each shell can have its own security settings and path formats

• Flexible Path Management: Different shells support different path formats (Windows/Unix/Mixed)

• Resource Exposure: View configuration and security settings as MCP resources

• Explicit Working Directory State: The server maintains an active working directory used when execute_command omits workingDir. If the launch directory isn't allowed, this state starts unset and must be set via set_current_directory.

• Optional Initial Directory: Configure initialDir to start the server in a specific directory.

• Security Controls:

  • Command blocking (full paths, case variations)

  • Working directory validation

  • Maximum command length limits

  • Smart argument validation

  • Shell-specific timeout settings

• Configurable:

  • Inheritance-based configuration system

  • Shell-specific security overrides

  • Dynamic tool descriptions based on enabled shells

See the API section for more details on the tools and resources the server provides to MCP clients.

Note: The server will only allow operations within configured directories, with allowed commands.

Modular Shell Architecture

WCLI0 now supports a modular architecture that allows you to build specialized versions containing only the shells you need. This results in significantly smaller bundle sizes and faster startup times.

Build Options

Choose from several pre-configured builds:

Bundle Size Comparison

Documentation

For detailed information about the modular architecture:

• Architecture Overview - System design and module structure

• User Guide - How to build and use specialized versions

• API Documentation - Complete API reference for shell plugins

• Migration Guide - Upgrading from previous versions

• Testing Guide - Testing strategies for modular shells

Quick Start with Specialized Builds

If you only need Git Bash:

Log Management

wcli0 automatically stores command execution logs and provides MCP resources for querying historical output with advanced filtering capabilities.

Output Truncation

By default, command responses show only the last 20 lines to prevent overwhelming long outputs. Full output is always stored and accessible via:

• File-based storage: When logDirectory is configured, logs are saved to files for persistent storage

• In-memory storage: Default behavior using MCP log resources (e.g., cli://logs/commands/{id})

• The get_command_output tool (fallback for hosts that cannot read resources)

Configure truncation settings:

File-Based Log Storage

For persistent logging, configure a log directory:

Or via CLI:

When file-based logging is enabled:

• Truncation messages show the file path directly (simpler output)

• Logs persist across server restarts

• No in-memory storage limits apply

• Starting the server with --debug automatically enables file-based logging to your OS temp directory (<temp>/wcli0-debug-logs) when no logDirectory is set, so every command and its output are persisted during debugging sessions.

Security Note: Log files may contain sensitive command output. Ensure the log directory has appropriate permissions.

Log Resources

Access stored command output via MCP resources (in-memory mode):

• cli://logs/list - List all stored command execution logs

• cli://logs/recent?n=10 - Get the N most recent logs

• cli://logs/commands/{id} - Access full output from a specific command

• cli://logs/commands/{id}/range?start=1&end=100 - Query specific line ranges

• cli://logs/commands/{id}/search?q=error&context=3 - Search logs with context

See API Documentation for detailed resource specifications and query parameters.

Example Configuration

Usage with Claude Desktop

Add this to your claude_desktop_config.json:

For use with a specific config file, add the --config flag:

Configuration Setup

To get started with configuration:

1. Use a sample configuration:

   • Copy config.examples/config.sample.json for basic setup

   • Copy config.examples/config.development.json for development environments

   • Copy config.examples/config.secure.json for high-security environments

   • Copy config.examples/emptyRestrictions.json to remove all default restrictions

2. Create your own configuration:

   # Copy and customize a sample cp config.examples/config.sample.json my-config.json # Or generate a default config npx wcli0 --init-config ./my-config.json

   The server also accepts an --initialDir flag to override the initial working directory defined in your configuration file:

   npx wcli0 --config ./my-config.json --initialDir /path/to/start

   You can override global command limits directly from the CLI:

   npx wcli0 --config ./my-config.json \ --maxCommandLength 5000 --commandTimeout 60

   You can configure output truncation and logging via CLI:

   npx wcli0 --shell gitbash \ --maxOutputLines 50 \ --enableTruncation \ --enableLogResources \ --maxReturnLines 1000 \ --logDirectory ./logs

   Option	Type	Default	Description
   --maxOutputLines	number	20	Maximum output lines before truncation
   --enableTruncation	boolean	true	Enable output truncation
   --enableLogResources	boolean	true	Enable log resources for get_command_output
   --maxReturnLines	number	500	Maximum lines returned by get_command_output
   --logDirectory	string	-	Directory for file-based log storage (instead of in-memory)

   When --logDirectory is configured, command output logs are saved to files instead of in-memory storage. Truncation messages will show the file path for easy access to full output.

   Security Note: Log files may contain sensitive data from command output. Ensure the log directory has appropriate permissions and consider implementing log rotation.

   You can override blocked restrictions directly from the CLI. Pass the option with an empty string to clear defaults:

   npx wcli0 --blockedCommand "" --blockedArgument "" --blockedOperator ""

   Provide the flag multiple times to specify values:

   npx wcli0 --blockedCommand rm --blockedCommand del

   You can also start the server with a specific shell and allowed directories without a configuration file:

   npx wcli0 --shell powershell \ --allowedDir C:\safe --allowedDir D:\projects

   For WSL shells, you can specify a custom mount location:

To disable directory restrictions entirely when no allowed paths are configured, start the server with:

When started this way, restrictWorkingDirectory is forced on and enableInjectionProtection is disabled to ensure the allowed paths apply without shell injection checks.

If you need to disable safety checks that block command execution for experimentation, you can start the server in unsafe or YOLO modes (not recommended for production):

Both modes clear blocked commands/arguments/operators and turn off injection protection. YOLO mode leaves working directory restrictions active, while fully unsafe mode disables those restrictions as well. These two flags are mutually exclusive; using both at once will fail.

1. Update your Claude Desktop configuration to use your config file:

   { "mcpServers": { "windows-cli": { "command": "npx", "args": [ "-y", "wcli0", "--config", "./my-config.json" ] } } }

After configuring, you can:

• Execute commands directly using the available tools

• View server configuration and security settings in the Resources section

• Access shell-specific configurations and capabilities

Configuration

The server uses an inheritance-based configuration system where global defaults can be overridden by shell-specific settings.

Configuration Structure

Configuration Locations

The server looks for configuration files in the following order:

1. Path specified via --config command line argument

2. win-cli-mcp.config.json in the current working directory

3. ~/.win-cli-mcp/config.json in user's home directory

If no configuration file is found, the server will use a default (restricted) configuration.

Default Configuration

Note: The default configuration is designed to be restrictive and secure. Find more details on each setting in the Configuration Settings section.

For a complete reference of all default values, see docs/defaults.md.

Configuration Settings

The configuration file uses an inheritance system with two main sections: global and shells.

Global Settings

Global settings provide defaults that apply to all shells unless overridden.

Security Settings

Restriction Settings

Path Settings

If the allowedPaths array is omitted from your configuration file, no default directories are automatically allowed. When restrictWorkingDirectory is enabled, only the initialDir (if specified) will be added to the allowed paths list. Use the --allowAllDirs flag when launching the server to automatically disable restrictWorkingDirectory if no allowed paths or initialDir are set.

Shell Configuration

Each shell can be individually configured and can override global settings. Each shell entry must include a type field indicating the shell. Valid values are powershell, cmd, gitbash, bash, and wsl.

Basic Shell Configuration

Shell-Specific Overrides

WSL Configuration

WSL shells have additional configuration options for path mapping:

You can override the mount point at startup using the --wslMountPoint CLI flag.

Configuration Inheritance

The inheritance system works as follows:

1. Global defaults are applied to all shells

2. Shell-specific overrides replace or extend global settings

3. Array settings (like blockedCommands) override defaults when provided. Specifying an empty array removes all default entries for that setting.

4. Object settings are deep-merged

5. Primitive settings are replaced

Example of inheritance in action:

Results in PowerShell having:

• commandTimeout: 45 (overridden)

• blockedCommands: ["Remove-Item"] (overrides defaults)

To completely remove defaults for a given restriction, provide an empty array:

API

Tools

• execute_command

  • Execute a command in the specified shell

  • Inputs:

    • shell (string): Shell to use ("powershell", "cmd", "gitbash", "bash", or "wsl")

    • command (string): Command to execute

    • workingDir (optional string): Working directory

  • Returns command output as text, or error message if execution fails

  • If workingDir is omitted, the command runs in the server's active working directory. If this has not been set, the tool returns an error.

• get_current_directory

  • Get the server's active working directory

  • If the directory is not set, returns a message explaining how to set it

• set_current_directory

  • Set the server's active working directory

  • Inputs:

    • path (string): Path to set as current working directory

  • Returns confirmation message with the new directory path, or error message if the change fails

• get_config

  • Get the windows CLI server configuration

  • Returns the server configuration as a JSON string (excluding sensitive data)

• validate_directories

  • Check if specified directories are within allowed paths

  • Only available when restrictWorkingDirectory is enabled in configuration

  • Inputs:

    • directories (array of strings): List of directory paths to validate

  • Returns success message if all directories are valid, or error message detailing which directories are outside allowed paths

Resources

• cli://config

  • Returns the main CLI server configuration (excluding sensitive data like blocked command details if security requires it).

• cli://logs/list

  • List all stored command execution logs with metadata

• cli://logs/recent?n={count}

  • Get the N most recent command logs (default: 5)

• cli://logs/commands/{id}

  • Access full output from a specific command execution

• cli://logs/commands/{id}/range?start={n}&end={m}

  • Query specific line ranges from a log (supports negative indices)

• cli://logs/commands/{id}/search?q={pattern}&context={n}&occurrence={n}

  • Search logs with regex patterns and context lines

Security Considerations

This server allows external tools to execute commands on your system. Exercise extreme caution when configuring and using it.

Built-in Security Features

• Path Restrictions: Commands can only be executed in specified directories (allowedPaths) if restrictWorkingDirectory is true.

• Command Blocking: Defined commands and arguments are blocked to prevent potentially dangerous operations (blockedCommands, blockedArguments).

• Injection Protection: Common shell injection characters (;, &, |, `) are blocked in command strings if enableInjectionProtection is true.

• Timeout: Commands are terminated if they exceed the configured timeout (commandTimeout).

• Input validation: All user inputs are validated before execution

• Shell process management: Processes are properly terminated after execution or timeout

Configurable Security Features (Active by Default)

• Working Directory Restriction (: HIGHLY RECOMMENDED. Limits command execution to safe directories.

• Injection Protection (: Recommended to prevent bypassing security rules.

Best Practices

• Minimal Allowed Paths: Only allow execution in necessary directories.

• Restrictive Blocklists: Block any potentially harmful commands or arguments.

• Regularly Review Logs: Check the command history for suspicious activity.

• Keep Software Updated: Ensure Node.js, npm, and the server itself are up-to-date.

Using the MCP Inspector for Testing

Use the Inspector to interactively test this server with a custom config file. Pass any server flags after --:

Development and Testing

This project requires Node.js 18 or later.

Running Tests

Cross-Platform Testing

The project uses a Node.js-based WSL emulator (scripts/wsl-emulator.js) to enable testing of WSL functionality on all platforms. This allows the test suite to run successfully on both Windows and Linux environments.

Acknowledgments

This project is based on the excellent work by SimonB97 in the win-cli-mcp-server repository. Due to significant configuration differences and architectural changes that made merging back to the source repository challenging, this has been maintained as a separate fork with enhanced features and extensive modifications.

Key enhancements in this version:

• Enhanced inheritance-based configuration system

• Improved WSL support with cross-platform testing

• Advanced security features and path validation

• Comprehensive test coverage with Node.js-based WSL emulation

• Extended documentation and configuration examples

We gratefully acknowledge SimonB97's foundational work that made this project possible.

Development Environment using Dev Containers

This project includes a Dev Container configuration, which allows you to use a Docker container as a fully-featured development environment. This ensures consistency and makes it easy to get started with development and testing.

Prerequisites

• Docker Desktop installed and running.

• Visual Studio Code installed.

• The Dev Containers extension installed in VS Code.

Getting Started

1. Clone this repository to your local machine.

2. Open the repository in Visual Studio Code.

3. When prompted "Reopen in Container", click the button. (If you don't see a prompt, you can open the Command Palette (Ctrl+Shift+P or Cmd+Shift+P) and select "Dev Containers: Reopen in Container".)

4. VS Code will build the dev container image (as defined in .devcontainer/devcontainer.json and Dockerfile) and start the container. This might take a few minutes the first time.

5. Once the container is built and started, your VS Code will be connected to this environment. The postCreateCommand (npm install) will ensure all dependencies are installed.

Running Tests in the Dev Container

After opening the project in the dev container:

1. Open a new terminal in VS Code (it will be a terminal inside the container).

2. Run the tests using the command:

   npm test

This setup mirrors the environment used in GitHub Actions for tests, ensuring consistency between local development and CI.

License

This project is licensed under the MIT License. See the LICENSE file for details.