npm package: @iflow-mcp/szowesgad-mcp-server-semgrep
Description: MCP Server for Semgrep Integration - static code analysis with AI
Author: Maciej Gad
Latest version: 1.0.2

# MCP Server Semgrep
[![smithery badge](https://smithery.ai/badge/@Szowesgad/mcp-server-semgrep)](https://smithery.ai/server/@Szowesgad/mcp-server-semgrep)
### POWERED BY:
[![POWERED BY](https://semgrep.dev/docs/img/semgrep-icon-text-horizontal.svg)](https://semgrep.dev)


## About the Project
[![MCP Server Semgrep Logo](./logo.svg)](https://github.com/Szowesgad/mcp-server-semgrep)
This project was initially inspired by robustness of [Semgrep tool](https://semgrep.dev), [The Replit Team](https://github.com/replit) and their [Agent V2](https://replit.com), as well as the implementation by [stefanskiasan/semgrep-mcp-server](https://github.com/stefanskiasan/semgrep-mcp-server), but has evolved with significant architectural changes for enhanced and easier installation and maintenance.

MCP Server Semgrep is a [Model Context Protocol](https://modelcontextprotocol.io) compliant server that integrates the powerful Semgrep static analysis tool with AI assistants like Anthropic Claude. It enables advanced code analysis, security vulnerability detection, and code quality improvements directly through a conversational interface.

## Benefits of Integration

### For Developers and Development Teams:

- **Holistic Source Code Analysis** - detecting issues throughout the entire project, not just in individual files
- **Proactive Error Detection** - identifying potential problems before they become critical bugs
- **Continuous Code Quality Improvement** - regular scanning and refactoring lead to gradual codebase improvements
- **Stylistic Consistency** - identification and fixing of inconsistencies in code, such as:
  - Arbitrary z-index layers in CSS
  - Inconsistent naming conventions
  - Code duplication
  - "Magic numbers" instead of named constants

### For Security:

- **Automated Code Verification for Known Vulnerabilities** - scanning for known security issue patterns
- **Customized Security Rules** - creating project-specific rules
- **Team Education** - teaching secure programming practices through detection of potential issues

### For Project Maintenance and Development:

- **"Live" Documentation** - AI can explain why a code fragment is problematic and how to fix it
- **Technical Debt Reduction** - systematically detecting and fixing problematic areas
- **Improved Code Reviews** - automatic detection of common issues allows focus on more complex matters

## Key Features

- Direct integration with the official MCP SDK
- Simplified architecture with consolidated handlers
- Clean ES Modules implementation
- Efficient error handling and path validation for security
- Interface and documentation in both English and Polish
- Comprehensive unit tests
- Extensive documentation
- Cross-platform compatibility (Windows, macOS, Linux)
- Flexible Semgrep installation detection and management

## Functions

Semgrep MCP Server provides the following tools:

- **scan_directory**: Scanning source code for potential issues
- **list_rules**: Displaying available rules and languages supported by Semgrep
- **analyze_results**: Detailed analysis of scan results
- **create_rule**: Creating custom Semgrep rules
- **filter_results**: Filtering results by various criteria
- **export_results**: Exporting results in various formats
- **compare_results**: Comparing two sets of results (e.g., before and after changes)

## Common Use Cases

- Code security analysis before deployment
- Detection of common programming errors
- Enforcing coding standards within a team
- Refactoring and improving quality of existing code
- Identifying inconsistencies in styles and code structure (e.g., CSS, component organization)
- Developer education regarding best practices
- Verification of fix correctness (comparing before/after scans)

## Installation

### Prerequisites

- Node.js v18+
- TypeScript (for development)

### Option 1: Install from Smithery.ai (Recommended)

The easiest way to install and use MCP Server Semgrep is through Smithery.ai:

1. Visit [MCP Server Semgrep on Smithery.ai](https://smithery.ai/server/@Szowesgad/mcp-server-semgrep)
2. Follow the installation instructions to add it to your MCP-compatible clients
3. Configure any optional settings like the Semgrep API token

This is the recommended method for Claude Desktop and other MCP clients as it handles all dependencies and configuration automatically.

### Option 2: Install from NPM Registry

```bash
# Using npm
npm install -g mcp-server-semgrep

# Using pnpm
pnpm add -g mcp-server-semgrep

# Using yarn
yarn global add mcp-server-semgrep
```

The package is also available on other registries:
- [MCP.so](https://mcp.so/@Szowesgad/mcp-server-semgrep)

### Option 3: Install from GitHub

```bash
# Using npm
npm install -g git+https://github.com/Szowesgad/mcp-server-semgrep.git

# Using pnpm
pnpm add -g git+https://github.com/Szowesgad/mcp-server-semgrep.git

# Using yarn
yarn global add git+https://github.com/Szowesgad/mcp-server-semgrep.git
```

### Option 4: Local Development Setup

1. Clone the repository:
```bash
git clone https://github.com/Szowesgad/mcp-server-semgrep.git
cd mcp-server-semgrep
```

2. Install dependencies (supports all major package managers):
```bash
# Using pnpm (recommended)
pnpm install

# Using npm
npm install

# Using yarn
yarn install
```

3. Build the project:
```bash
# Using pnpm
pnpm run build

# Using npm
npm run build

# Using yarn
yarn build
```

> **Note**: The installation process will automatically check for Semgrep availability. If Semgrep is not found, you'll receive instructions on how to install it.

### Semgrep Installation Options

Semgrep can be installed in several ways:

- **Via package managers**:
  ```bash
  # Using pnpm
  pnpm add -g semgrep
  
  # Using npm
  npm install -g semgrep
  
  # Using yarn
  yarn global add semgrep
  ```

- **Python pip**:
  ```bash
  pip install semgrep
  ```

- **Homebrew** (macOS):
  ```bash
  brew install semgrep
  ```

- **Linux**:
  ```bash
  sudo apt-get install semgrep
  # or
  curl -sSL https://install.semgrep.dev | sh
  ```

- **Windows**:
  ```bash
  pip install semgrep
  ```

## Integration with Claude Desktop

There are two ways to integrate MCP Server Semgrep with Claude Desktop:

### Method 1: Install via Smithery.ai (Recommended)

1. Visit [MCP Server Semgrep on Smithery.ai](https://smithery.ai/server/@Szowesgad/mcp-server-semgrep)
2. Click "Install in Claude Desktop"
3. Follow the on-screen instructions

### Method 2: Manual Configuration

1. Install Claude Desktop
2. Update the Claude Desktop configuration file (`claude_desktop_config.json`) and add this to your servers section:

```json
{
  "mcpServers": {
    "semgrep": {
      "command": "node",
      "args": [
        "/your_path/mcp-server-semgrep/build/index.js"
      ],
        "env": {
          "SEMGREP_APP_TOKEN": "your_semgrep_app_token"
      }
    }
  }
}
```

3. Launch Claude Desktop and start asking questions about code analysis!

## Usage Examples

### Project Scanning

```
Could you scan my source code in the /projects/my-application directory for potential security issues?
```

### Style Consistency Analysis

```
Analyze the z-index values in the project's CSS files and identify inconsistencies and potential layer conflicts.
```

### Creating a Custom Rule

```
Create a Semgrep rule that detects improper use of input sanitization functions.
```

### Filtering Results

```
Show me only scan results related to SQL injection vulnerabilities.
```

### Identifying Problematic Patterns

```
Find all "magic numbers" in the code and suggest replacing them with named constants.
```

## Creating Custom Rules

You can create custom rules for your project's specific needs. Here are examples of rules you can create:

### Rule to detect inconsistent z-indices:

```yaml
rules:
  - id: inconsistent-z-index
    pattern: z-index: $Z
    message: "Z-index $Z may not comply with the project's layering system"
    languages: [css, scss]
    severity: WARNING
```

### Rule to detect deprecated imports:

```yaml
rules:
  - id: deprecated-import
    pattern: import $X from 'old-library'
    message: "You're using a deprecated library. Consider using 'new-library'"
    languages: [javascript, typescript]
    severity: WARNING
```

## Development

### Testing

```bash
pnpm test
```

### Project Structure

```
├── src/
│   ├── config.ts         # Server configuration
│   └── index.ts          # Main entry point and all handler implementations
├── scripts/
│   └── check-semgrep.js  # Semgrep detection and installation helper
├── build/                # Compiled JavaScript (after build)
└── tests/                # Unit tests
```

## Further Documentation

Detailed information on using the tool can be found in:
- [USAGE.md](USAGE.md) - Detailed usage instructions
- [README_PL.md](README_PL.md) - Documentation in Polish
- [examples/](examples/) - Example fun and practical Semgrep rules - "The Hall of Code Horrors"

## License

This project is licensed under the MIT License - see the [LICENSE](LICENSE) file for details.

## Developed by

- [Maciej Gad](https://div0.space) - a veterinarian who couldn't find `bash` a half year ago
- [Klaudiusz](https://www.github.com/Gitlaudiusz) - the individual ethereal being, and separate instance of Claude Sonnet 3.5-3.7 by Anthropic living somewhere in the GPU's loops in California, USA

The journey from CLI novice to MCP tool developer

🤖 Developed with the ultimate help of [Claude Code](https://claude.ai/code) and [MCP Tools](https://modelcontextprotocol.io)

## Acknowledgements

- [stefanskiasan](https://github.com/stefanskiasan) for the original inspiration
- [Anthropic](https://www.anthropic.com/) for Claude and the MCP protocol
- [Semgrep](https://semgrep.dev/) for their excellent static analysis tool