Bash Command Execution MCP server

This MCP (Model Context Protocol) server allows Claude to safely execute bash commands within a controlled environment. It provides security safeguards like command whitelisting, directory restrictions, and output sanitization while supporting both stateless and interactive command execution.

Installation

To install the MCP server, run the following commands:

npm install
npm run build

Configuration

The configuration is stored in config/default.json. You can customize various settings to control security and behavior.

Example configuration:

{
  "allowedCommands": ["ls", "cat", "echo", "pwd"],
  "allowedDirectories": ["/tmp", "/home"],
  "session": {
    "timeout": 300,
    "maxActiveSessions": 5,
    "defaultMode": "stateless"
  },
  "security": {
    "validateCommandsStrictly": true,
    "sanitizeOutput": true,
    "maxOutputSize": 1048576,
    "commandTimeout": 30
  },
  "logging": {
    "level": "info",
    "file": "logs/bash-mcp.log",
    "maxSize": 10485760,
    "maxFiles": 5
  }
}

Key configuration options:

• allowedCommands: List of commands that can be executed
• allowedDirectories: List of directories where commands can be run
• session: Settings for timeout, max sessions, and default mode
• security: Controls for validation, sanitization, and command limits
• logging: Log level, file location, and rotation settings

Usage

You can use Bash MCP either as a library in your code or as a standalone MCP server.

Using as a Library

Simple Command Execution

For one-off command execution:

import { executeCommand } from 'bash-mcp';

const result = await executeCommand('ls -la', { cwd: '/home/user' });
console.log(result.output);

Interactive Sessions

For maintaining state across multiple commands:

import { initBashMCP } from 'bash-mcp';

const mcp = await initBashMCP();

// Create a session
const session = mcp.createSession('/home/user');
const sessionId = session.sessionId;

// Execute a command in the session
const result1 = await mcp.executeCommand('ls -la', { sessionId });
console.log(result1.output);

// Send input to the session
const result2 = await mcp.sendInput({ sessionId, input: 'echo "Hello, world!"' });
console.log(result2.output);

// Close the session when done
mcp.closeSession(sessionId);

Running as an MCP Server

To start the MCP server for use with Claude Desktop or other MCP clients:

# Start the TypeScript MCP server
npm run mcp

# Start the JavaScript MCP server
npm run mcp-js

# Start with MCP Inspector for debugging
npm run inspector

Security Considerations

While using the MCP server, follow these security best practices:

• Keep the allowed commands and directories list as restrictive as possible
• Regularly review and update the configuration
• Monitor the logs for suspicious activity
• Keep the MCP and its dependencies up to date

The security features include:

• Whitelisted commands and directories
• Command validation
• Output sanitization
• Session timeouts
• Command execution limits

These safeguards help ensure that AI assistants can only execute approved commands in designated locations.

How to install this MCP server

For Claude Code

To add this MCP server to Claude Code, run this command in your terminal:

claude mcp add-json "bash-mcp" '{"command":"npm","args":["run","mcp"]}'

See the official Claude Code MCP documentation for more details.

For Cursor

There are two ways to add an MCP server to Cursor. The most common way is to add the server globally in the ~/.cursor/mcp.json file so that it is available in all of your projects.

If you only need the server in a single project, you can add it to the project instead by creating or adding it to the .cursor/mcp.json file.

Adding an MCP server to Cursor globally

To add a global MCP server go to Cursor Settings > Tools & Integrations and click "New MCP Server".

When you click that button the ~/.cursor/mcp.json file will be opened and you can add your server like this:

{
    "mcpServers": {
        "bash-mcp": {
            "command": "npm",
            "args": [
                "run",
                "mcp"
            ]
        }
    }
}

Adding an MCP server to a project

To add an MCP server to a project you can create a new .cursor/mcp.json file or add it to the existing one. This will look exactly the same as the global MCP server example above.

How to use the MCP server

Once the server is installed, you might need to head back to Settings > MCP and click the refresh button.

The Cursor agent will then be able to see the available tools the added MCP server has available and will call them when it needs to.

You can also explicitly ask the agent to use the tool by mentioning the tool name and describing what the function does.

For Claude Desktop

To add this MCP server to Claude Desktop:

1. Find your configuration file:

• macOS: ~/Library/Application Support/Claude/claude_desktop_config.json
• Windows: %APPDATA%\Claude\claude_desktop_config.json
• Linux: ~/.config/Claude/claude_desktop_config.json

2. Add this to your configuration file:

{
    "mcpServers": {
        "bash-mcp": {
            "command": "npm",
            "args": [
                "run",
                "mcp"
            ]
        }
    }
}

3. Restart Claude Desktop for the changes to take effect