MCP Defender

MCP Defender is a desktop app for individuals running AI coding and chat tools that need real-time security for Model Context Protocol (MCP) traffic between AI apps and MCP servers.

It works as a secure proxy that intercepts MCP tool call requests and responses, then checks them for malicious activity before it reaches the AI app or connected tools:

• Real-time threat detection using multiple layers, including LLM-powered analysis and deterministic security signatures
• User alerts and approval workflows to allow or block suspicious tool activity
• Coverage for common attack classes such as prompt injection, credential theft, arbitrary code execution, and remote command injection
• Scan controls to manage signatures used during scanning, plus the option to choose an LLM provider and use personal API keys

Pricing: Undisclosed, contact for pricing.

Notable for being open source and AGPL-3.0 licensed, and for targeting MCP-specific risks by scanning tool calls in supported apps such as Cursor, Claude, Visual Studio Code, and Windsurf.