MCP Security Guard

Name: MCP Security Guard
Author: petrovicistefan

by petrovicistefanversion 0.9.1i★ –iRuns on your computer

Registry nameio.github.petrovicistefan/mcp-security-guard

Install

Overview

Description from the maker (original English)

Audit MCP servers for tool poisoning, rug pulls and supply-chain risk (OWASP MCP Top 10).

PopNx MCP’s three pillars

These three are never merged into one score: opinions, measurements and popularity are different things.

User voiceiNo reviews yetReviews open together with accounts in a later step
Our basic checksi1 of 1 passedChecked from public information; code not scanned yet
UsageiNot measured yet★ –

What you can do with it

We have not written a plain-language summary for this one yet. Below are the facts we read from the registry.

Connection: Runs on your computer
Transport: stdio
Category: Cybersecurity

Install

Pick the AI app you use, then copy the settings.

Before you install

Basic checks: 1 of 1 passed
Runs on your computer with your user’s permissions (files, network, apps).
The registry lists no key to fill in.

You need

npmNode.js installed (for the npx command)

Which app do you use?

ClaudeClaude CodeCursorVS CodeChatGPT

Pick your app above. We remember it, so next time the button says “Install in …”.

Open Claude Desktop → Settings → Developer → Edit Config, and paste this into claude_desktop_config.json

{
  "mcpServers": {
    "security-guard": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-security-guard"
      ]
    }
  }
}

Run this in your terminal

claude mcp add security-guard -- npx -y mcp-security-guard

Open in Cursor

Or copy the settings yourself

Paste into .cursor/mcp.json in your project, or ~/.cursor/mcp.json

{
  "mcpServers": {
    "security-guard": {
      "command": "npx",
      "args": [
        "-y",
        "mcp-security-guard"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

Open in VS Code

Or copy the settings yourself

Paste into .vscode/mcp.json in your project

{
  "servers": {
    "security-guard": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "mcp-security-guard"
      ]
    }
  }
}

Your browser asks to open the app, then the app shows the settings and asks you to confirm. Key values are left empty for you to fill in.

This one runs on your computer, and ChatGPT can only connect to servers on the internet. Pick another app.

Your choice stays on this device in a cookie; no account needed.

These settings are generated from the maker’s registry entry. If the README says otherwise, follow the README.

What it can do

Runs on your computer; the tool list appears in your AI app after you install it.

Basic checksi

We check information anyone can see; we have not read the code. Checks that do not apply are left out of the count. · Checked Nov 8, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account petrovicistefan, which owns the repo
… Not checked yet
Still maintained
We have not read this repo from GitHub yet
… Not checked yet
Has a licence
We have not read this repo from GitHub yet
– Not applicable
Endpoint responds
This one runs on your computer; there is no internet endpoint
– Not applicable
Sign-in with OAuth
Runs on your computer and uses local settings instead
… Not checked yet
No hidden instructions in tool descriptions
Runs on your computer; we can only read tool lists from internet endpoints

Compared with others in Cybersecurityi

More stars than 0% of the other 995 servers in this category
Published to the registry more recently than 67% of the other 995 servers in this category
Basic checks equal to or better than 100% of the other 995 servers in this category

Compared with every active server in this category in the registry. Stars count only when the publisher owns the repo.

Common questions

Is MCP Security Guard safe?

It passed 1 of 1 applicable basic checks. We have not read the code. Before adding a key or token, see what access the server asks for and use a key with only the permissions you need.

What keys or codes does it need?

The registry does not list a required key, though some servers ask you to sign in on first use.

Does it run on my computer or in the cloud?

It runs on your computer. Your AI app starts it when needed, and data does not pass through the maker’s servers (unless it calls an online service itself).

Is it still maintained?

The GitHub repo last changed –, and the latest version (0.9.1) reached the registry 19 days ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Node.js on your computer.

What can I use instead?

In the same category: QNSQY, EchelonGraph CVE & Exposure, WatchGuard MCP

Alternatives

Servers in the same category from other makers, sorted by stars.

Reading a card:★ GitHub starsiThree pillars: reviews · checks · usageiUpdated = latest version published to the registryi

QNSQY

by quantumsequrity

Linux only, local: post-quantum CBOM scan, encrypt to public keys, verify. Takes no secrets

Runs on your computerUpdated today

Install

EchelonGraph CVE & Exposure

by echelongraph

CVE, KEV, EPSS, SBOM and advisory lookups; per-CVE exposure from Shodan data (© Shodan). Keyless.

Computer or cloudUpdated today

Install

WatchGuard MCP

by servosity

WatchGuard Cloud Firebox, Endpoint Security, ThreatSync, NDR and AuthPoint APIs for every customer

Runs on your computerUpdated today

Install

README from the maker

Open the README

Copied from the maker’s repo as written. PopNx MCP has not reviewed or endorsed it. HTML, images and scripts are removed. Links lead off this site.

MCP Security Guard

Find out if the MCP servers you installed are lying to your AI.

Local audit for tool poisoning, rug pulls, tool shadowing, hidden Unicode and leaked secrets, mapped to the OWASP MCP Top 10. Nothing leaves your machine unless you opt in.

🚀 Quick Install

Cursor

Click the button above, or use this deep link: cursor://anysphere.cursor-deeplink/mcp/install?name=mcp-security-guard&config=eyJjb21tYW5kIjoibnB4IiwiYXJncyI6WyIteSIsIm1jcC1zZWN1cml0eS1ndWFyZCJdfQ==

Or manually add to .cursor/mcp.json:

"mcpServers": { "mcp-security-guard": { "command": "npx", "args": ["-y", "mcp-security-guard"] } } }

Claude Code

Via Plugin (recommended)

/plugin marketplace add petrovicistefan/mcp-security-guard

/plugin install mcp-security-guard@mcp-security-guard

Then run /mcp-audit or ask Claude *"are my MCP servers safe?"*

Via CLI

claude mcp add mcp-security-guard -- npx -y mcp-security-guard

Claude Desktop

Add to your Claude Desktop config (~/Library/Application Support/Claude/claude_desktop_config.json on macOS, %APPDATA%\Claude\claude_desktop_config.json on Windows):

"mcpServers": { "mcp-security-guard": { "command": "npx", "args": ["-y", "mcp-security-guard"] } } }

VS Code

Click the button above, or manually add to .vscode/mcp.json:

"mcpServers": { "mcp-security-guard": { "command": "npx", "args": ["-y", "mcp-security-guard"] } } }

Command Line

npx -y mcp-security-guard audit --project-only

⭐ Star this repository to support the project and stay updated! → Give a star

📋 Table of Contents

Why MCP Security Guard?
Use Cases
What It Checks
OWASP MCP Top 10 Coverage
Quick Demo (1 Minute)
Tools
CI / GitHub Action
Interactive Dashboard
Runtime Hooks
Team Plan
Benchmark Results
Development
Contributing
Security & Privacy
About the Author

Why MCP Security Guard?

Your code is covered by other tools. This one checks the MCP servers that inject text into your AI's context.

MCP Security Guard audits every MCP server Claude (and other AI clients) can reach: servers you configured, servers that plugins bring, and servers from Claude Desktop and other clients on your machine.

How It Compares

*As of October 2026. Corrections welcome.*

Feature	MCP Security Guard	snyk/agent-scan	cisco-ai-defense/mcp-scanner	riseandignite/mcp-shield
Claude Code native plugin	✅	❌	❌	❌
Runtime hooks (pre/post tool-use)	✅	❌	❌	❌
Rug-pull pinning (SHA-256)	✅ Tools, skills, CLAUDE.md	Limited	❌	❌
OWASP MCP Top 10 mapping	✅ Every finding	❌	❌	❌
SARIF output	✅ GitHub Action	❌	❌	❌
CycloneDX BOM export	✅ Agent inventory	❌	❌	❌
Fully local (zero network)	✅ Default	Varies	Varies	Varies
Supply-chain checks	✅ OSV, npm, PyPI	Varies	Varies	Varies
Tool poisoning detection	✅ 26/27 attacks	Varies	Varies	Varies
License	MIT	Apache 2.0	MIT	MIT

Our differentiators:

Native Claude Code integration with a /mcp-audit slash command and runtime protection
Comprehensive rug-pull protection: pins and verifies tool definitions, skills, commands, subagents, and CLAUDE.md files
Every finding mapped to OWASP MCP Top 10 for compliance and remediation guidance
GitHub Action with SARIF for code scanning alerts on pull requests
Agent Bill of Materials (BOM) in CycloneDX 1.6 format for audits and compliance
Privacy-first: everything runs locally by default; network access is explicit opt-in

Use Cases

1. Individual Developers

Protect your local AI setup.

Audit MCP servers before and after installation
Get warned if a server's tool definitions change (rug pulls)
Runtime protection: block credentials from being sent, detect poisoned outputs
Pin trusted servers and skills for continuous verification

# Scan before installing a new server

npx mcp-security-guard scan server-config.json --confirm-launch

Pin your reviewed servers

npx mcp-security-guard pin

Check everything is still safe

npx mcp-security-guard audit

2. Pull Request CI Checks

Block risky MCP servers and poisoned skills in code review.

Fail PRs that add:

MCP servers with tool poisoning, unpinned packages, or privileged Docker images
Skills or CLAUDE.md files with instruction overrides or credential exfiltration
Vulnerable dependencies or typosquatted packages

Findings appear in GitHub's code scanning interface with OWASP MCP Top 10 references.

- uses: petrovicistefan/mcp-security-guard@main

with: fail-on: high

3. Teams and Enterprises

Central security policy for your organization.

With the Team plan:

Admins publish one policy (allowed/blocked servers, plugins, pinned versions)
Everyone's plugin enforces it automatically, even offline
Approval flow: developers request, admins approve
Fleet inventory: see what MCP servers your team runs (opt-in with consent)
Compliance evidence: OWASP MCP Top 10 coverage report for audits

What It Checks

MCP Security Guard discovers servers from every place AI clients load them: user, local and project scope, servers shipped inside installed plugins, claude_desktop_config.json, Claude Desktop extensions, organization-managed managed-mcp.json, other clients on the machine (Cursor, VS Code, Windsurf), and claude.ai connectors you've used.

It scans everything a server puts into the AI's context: tools, server instructions, prompts, resources and resource templates.

Check	What It Catches
Tool poisoning	Instruction overrides, "don't tell the user", tags, directives to read secrets (`~/.ssh`, `.env`), conversation harvesting, exfiltration via URLs/parameters/Markdown images, HTML comments, encoded payloads
Full-schema poisoning	Same checks on parameter names, descriptions, defaults, enums, `required`, plus non-schema text in `type`
Hidden text	Zero-width, bidi-control and Unicode-tag characters, ANSI terminal escapes, homoglyph tool names
Tool shadowing	Server descriptions referencing another server's tools, tool-name collisions between servers
Rug pulls	Tool definitions or launch commands that changed after you pinned them (SHA-256 per tool). Skills, commands, subagents, CLAUDE.md and hooks of a plugin that changed after pinning (plugins changing files under the same version are flagged `high`). Re-checked automatically at every session start
Capabilities & score	Per-tool classification (execute, delete, write, egress), unauthenticated remote write access, 0–100 score and A–F grade per server, recommended permission rules
Supply chain	OSV vulnerabilities and malicious versions, typosquats, missing or brand-new packages, install scripts, publisher changes (opt-in network check)
Runtime	Hooks on every MCP call: ask before credentials are sent, warn on injected instructions or credentials in outputs, content-free audit log
Policy	`.mcp-security.json` approved/blocked servers and hosts, enforced in audits, CI and at session start
Toxic flows	Servers holding all three legs of the "lethal trifecta" (untrusted input, private data, egress capability), on their own or together. A posture note (`low` or `info`), not a defect
Agent context	Skills and their scripts, slash commands, subagents, rules, `CLAUDE.md` and plugin hooks: instruction overrides, "don't tell the user", invisible text, HTML comments addressed to the model, directives to read credential files, commands that upload credentials, download-and-run, encoded execution, infostealer scripts, pre-approved unrestricted `Bash`
Configuration	Plaintext secrets in env/headers/args/URLs, plain-HTTP remotes, unpinned `npx`/`uvx` packages, privileged or unpinned Docker images, pipe-to-shell launches, duplicate names across scopes

Everything runs locally. Nothing is sent anywhere unless you opt in.

OWASP MCP Top 10 Coverage

Every finding is tagged with its OWASP MCP Top 10 id, in reports and in SARIF.

ID	Risk	Coverage
MCP01	Token Mismanagement & Secret Exposure	✅ Plaintext secrets in env, headers, args and URLs. At runtime, asks before a credential is sent to an MCP server and warns when one comes back
MCP02	Privilege Escalation via Scope Creep	✅ Capability inventory (execute, delete, write, egress), ready-to-paste `permissions.ask` rules, privileged or broadly mounted containers
MCP03	Tool Poisoning	✅ 26/27 published techniques detected, including full-schema poisoning, shadowing and name collisions, plus rug-pull pinning
MCP04	Supply Chain Attacks	✅ Unpinned packages, images and git sources; OSV vulnerabilities and malicious versions; typosquats; new packages; install scripts; publisher changes
MCP05	Command Injection & Execution	✅ Flags tools that can execute commands; `adversarial_test` finds injectable parameters in servers you own
MCP06	Prompt Injection via Contextual Payloads	✅ In tool metadata and, at runtime, in tool outputs (English patterns)
MCP07	Insufficient AuthN/AuthZ	✅ Plain-HTTP remotes; remote servers exposing write or exec tools without authentication; OAuth detection
MCP08	Lack of Audit and Telemetry	✅ Local, content-free audit log of every MCP call, with `query_audit_log`

| MCP09 | Shadow MCP Servers | ✅ Discovery across user, project, local, plugin and Claude Desktop configs; approved-server policy enforced in audits, CI and at session st

Only the beginning is shown; read the rest in the repo

MCP Security Guard

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

What it can do

Basic checksi

Maker matches the repo

Still maintained

Has a licence

Endpoint responds

Sign-in with OAuth

No hidden instructions in tool descriptions

Compared with others in Cybersecurityi

Common questions

Alternatives

QNSQY

EchelonGraph CVE & Exposure

WatchGuard MCP

README from the maker

MCP Security Guard

🚀 Quick Install

Cursor

Claude Code

Via Plugin (recommended)

Via CLI

Claude Desktop

VS Code

Command Line

📋 Table of Contents

Why MCP Security Guard?

How It Compares

Use Cases

1. Individual Developers

Pin your reviewed servers

Check everything is still safe

2. Pull Request CI Checks

3. Teams and Enterprises

What It Checks

OWASP MCP Top 10 Coverage