MCP Defender

Name: MCP Defender
Author: MCP-Defender

by MCP-Defender

Desktop app that automatically scans and blocks malicious MCP traffic in AI apps like Cursor, Claude, VS Code and Windsurf.

253 0 tools GitHub

No known CVEs

AGPL-3.0 license

Stale

Last commit 256d ago

Works with most clients

Transport: sse, http

0 tools

Grade F

Edit this pageView history

Security AI / ML

Step 1

Install in your client

Config is the same across clients — only the file and path differ.

Supported in Claude Desktopsse, http · Node 18+

Paste into ~/Library/Application Support/Claude/claude_desktop_config.json

{
  "mcpServers": {
    "mcp-defender": {
      "command": "<see-readme>",
      "args": []
    }
  }
}

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[![MCPpedia Score](https://mcppedia.org/api/badge/mcp-defender)](https://mcppedia.org/s/mcp-defender)

Read me

What MCP Defender does

🛡️ MCP Defender is a desktop app that protects AI apps like Cursor from a variety of attacks.

Test This Server

This server supports HTTP transport. Be the first to test it — help the community know if it works.

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Why this score

Five weighted categories — click any category to see the underlying evidence.

Score breakdown

32/100across 5 weighted dimensions

How we score →

0255075100

−68

Security

Maintenance

Efficiency

Documentation

Compatibility

Categoriesclick a row to see evidence

Security

OSV.dev

No known CVEs.

No package registry to scan.

Community

Reviews

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Share your experience — it helps other developers decide.

How easy was setup?Did it work reliably?How was the documentation?

Frequently Asked Questions

Is MCP Defender safe to use?: MCP Defender has no known CVEs as of the latest MCPpedia security scan. It does not require authentication, so any local process can connect — keep this in mind in shared environments. Licensed under AGPL-3.0.
How do I install MCP Defender?: MCP Defender can be installed by cloning its GitHub repository and following the setup instructions in the README.
What AI clients work with MCP Defender?: MCP Defender is compatible with claude-desktop, cursor, claude-code, windsurf. It uses sse and http transport.
Is MCP Defender actively maintained?: MCP Defender is less actively maintained — last commit was 256 days ago. It has 253 GitHub stars.

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Community

Discussion

Start a conversation

Ask a question, share a tip, or report an issue.

Has anyone used this with Cursor?How do you handle auth?Any alternatives?

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.

Frequently Asked Questions

Is MCP Defender safe to use?

MCP Defender has no known CVEs as of the latest MCPpedia security scan. It does not require authentication, so any local process can connect — keep this in mind in shared environments. Licensed under AGPL-3.0.

How do I install MCP Defender?

MCP Defender can be installed by cloning its GitHub repository and following the setup instructions in the README.

What AI clients work with MCP Defender?

MCP Defender is compatible with claude-desktop, cursor, claude-code, windsurf. It uses sse and http transport.

Is MCP Defender actively maintained?

MCP Defender is less actively maintained — last commit was 256 days ago. It has 253 GitHub stars.

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

Download MCP Defender for Mac

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.