Defender
FreeNot checkedDesktop app that automatically scans and blocks malicious MCP traffic in AI apps like Cursor, Claude, VS Code and Windsurf.
About
Desktop app that automatically scans and blocks malicious MCP traffic in AI apps like Cursor, Claude, VS Code and Windsurf.
README
MCP Defender
Automatically protects MCP traffic in AI apps
MCP Defender has been acquired by Docker Inc.
🛡️ MCP Defender is a desktop app that protects AI apps like Cursor from a variety of attacks.
🚦 All MCP tool call requests and responses from AI apps are automatically proxied through MCP Defender.
🔎 The intercepted data is then checked against a set of signatures.
🔐 If anything harmful is detected, MCP Defender alerts you and asks if you want to allow or block the tool call.
Demos
https://github.com/user-attachments/assets/363ae2b1-e395-4cdc-b5ca-e9862baf89c3
Quick Start
Alternatively you can clone the git repo, and run it as follows:
# Install dependencies
npm install
# Start app
npm start
Which apps are automatically protected?
MCP Defender protects Cursor, Claude, Visual Studio Code and Windsurf.
License
MCP Defender is licensed under the AGPL-3.0 license. For more details, see the LICENSE.
Installing Defender
This server has no published package — it is built from source. Open the repository and follow its README.
▸ github.com/MCP-Defender/MCP-DefenderFAQ
Is Defender MCP free?
Yes, Defender MCP is free — one-click install via Unyly at no cost.
Does Defender need an API key?
No, Defender runs without API keys or environment variables.
Is Defender hosted or self-hosted?
Self-hosted: the server runs locally on your machine via the install command above.
How do I install Defender in Claude Desktop, Claude Code or Cursor?
Open Defender on unyly.org, pick your client tab (Claude Desktop, Claude Code, Cursor) and press Install — the config is generated automatically, no JSON editing.
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