MCP-Bastion

Name: MCP-Bastion
Author: vaquarkhan

by vaquarkhanversion 5.1.0i★ 7iRuns on your computer

Registry nameio.github.vaquarkhan/mcp-bastion

Install

Overview

Description from the maker (original English)

Security middleware for MCP. Blocks prompt injection, PII leakage, and resource exhaustion.

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 checksi2 of 2 passedChecked from public information; code not scanned yet
UsageiEarly↓ 189/wk · ★ 7

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: 2 of 2 passed
Runs on your computer with your user’s permissions (files, network, apps).
The registry lists no key to fill in.

You need

PyPIPython’s uv installed (for the uvx 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": {
    "bastion": {
      "command": "uvx",
      "args": [
        "mcp-bastion-python"
      ]
    }
  }
}

Run this in your terminal

claude mcp add bastion -- uvx mcp-bastion-python

Open in Cursor

Or copy the settings yourself

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

{
  "mcpServers": {
    "bastion": {
      "command": "uvx",
      "args": [
        "mcp-bastion-python"
      ]
    }
  }
}

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": {
    "bastion": {
      "type": "stdio",
      "command": "uvx",
      "args": [
        "mcp-bastion-python"
      ]
    }
  }
}

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.

Which apps can use it

Based on how this server connects and on each app’s own docs, checked Nov 10, 2026.

Run on your computer in

Claude Goose LM Studio Msty Studio Cherry Studio Cursor VS Code + GitHub Copilot Visual Studio Windsurf (Devin Desktop)Zed Kiro Cline Continue JetBrains AI Assistant Claude Code Codex CLI Gemini CLI OpenCode nodecode Warp LibreChat Raycast

All apps, with pros and cons →

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 10, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account vaquarkhan, which owns the repo
✓ Pass
Still maintained
Code last changed yesterday
… 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 90% of the other 1018 servers in this category
Published to the registry more recently than 35% of the other 1018 servers in this category
Basic checks equal to or better than 100% of the other 1018 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-Bastion safe?

It passed 2 of 2 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 yesterday, and the latest version (5.1.0) reached the registry 3 months ago.

Which apps can use it?

Apps that support MCP, such as Claude Desktop, Claude Code, Cursor and VS Code. You also need Python (uv) on your computer.

What can I use instead?

In the same category: Robin: AI-Powered Dark Web OSINT, HOL Guard, UniFi Network MCP

Alternatives

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

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

Robin: AI-Powered Dark Web OSINT

Dark web OSINT over Tor: search onion engines, scrape pages, report with your own model.

by apurvsinghgautamGrowing★ 7.9KUpdated 39 days ago

Runs on your computer

Install

HOL Guard

Local-first AI agent security evidence and approval workflows through HOL Guard's stdio MCP server.

by hashgraph-onlineWidely used↓ 7.1K/wk★ 1.1KUpdated 6 days ago

Runs on your computer

Install

UniFi Network MCP

Manage UniFi Network devices, clients, firewall, VLANs, VPNs, and more via MCP.

by sirkirbyWidely used↓ 11.3K/wk★ 1KUpdated 8 months ago

Runs on your computer

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-Bastion

README · Documentation · Demos · Dashboard / Observability · Multi-language · Benchmark · License · Security

Current release: [5.1.0](https://pypi.org/project/mcp-bastion-python/5.1.0/) · Docker v5.1.0 · 26 PyPI packages · CHANGELOG

Go to	Link
Docs / demos	https://vaquarkhan.github.io/MCP-Bastion/ · product tour video · integrations
Benchmark / security deck (PDF)	[MCP-Security-Deck-v3.pdf](MCP-Security-Deck-v3.pdf) · raw download
Documentation handbook	https://vaquarkhan.github.io/MCP-Bastion/guide/handbook.html
Demos (attacks, dashboard, payloads, all languages)	https://vaquarkhan.github.io/MCP-Bastion/guide/demos.html
Dashboard & observability (OTEL optional)	https://vaquarkhan.github.io/MCP-Bastion/guide/observability.html
Multi-language suite	https://vaquarkhan.github.io/MCP-Bastion/guide/multi-language.html · suite repo
MCP Test Harness (sister product — CI gate for MCP servers)	https://github.com/vaquarkhan/mcp-test-harness · use with Bastion E2E
Docs hub	https://vaquarkhan.github.io/MCP-Bastion/guide/
Measured benchmarks (reproducible)	docs/BENCHMARKS.md

The Zero-Trust control plane for MCP agents. Your agent can call databases, APIs, and shell tools. One bad prompt can leak PII; one runaway loop can burn your API budget in minutes; three agents on one server with no identity boundary is a confused-deputy incident waiting to happen. MCP-Bastion wraps your MCP server with local guardrails: agent IAM, supply-chain checksums, injection blocking, PII redaction, and denial-of-wallet caps, under 5ms overhead, with no third-party safety API.

Guiding rule: Stay a zero-infra, drop-in library - the guardrail brain that composes with any gateway, not a gateway itself. Strategy: docs/ZERO_INFRA_STRATEGY.md.

Measured proof (offline, reproducible)

Slide deck (share with evaluators): [MCP-Security-Deck-v3.pdf](MCP-Security-Deck-v3.pdf) — security + FinOps proof pack (direct download).

Gate	Result	How to reproduce
Injection heuristics	100% attack block · 0% benign FP on the published corpus	`pytest tests/test_injection_efficacy.py` · docs/BENCHMARKS.md
Tool catalog scan	Injection / secrets / homoglyphs / shadow tools / nested weak schemas	`mcp-bastion scan examples/fixtures/tools-poisoned.json`
FinOps	Up to ~99.7% output-budget savings · ~85% fewer discovery tokens	docs/BENCHMARKS.md
Toxic-flow taint	Session PII/secret → egress tool with URL/email args blocked in-process	`toxic_flow` in `bastion.yaml` · docs/THREAT_MODEL.md

Scan → Test → Enforce (no other tool has all three)

Phase	What	Command
Scan	Static tool-definition checks before deploy (injection, secrets, homoglyphs, fingerprint drift, schema preconditions)	`mcp-bastion scan tools.json`
Audit	Local MCP client-config risk report (over-broad tools, standing credentials, filesystem servers)	`mcp-bastion audit`
Test	Integrated red-team against `bastion.yaml` + pair with [MCP Test Harness](https://github.com/vaquarkhan/mcp-test-harness) in CI	`mcp-bastion redteam` · docs/BASTION_AND_TEST_HARNESS.md
Enforce	Runtime middleware on every MCP method	`secure_fastmcp(mcp)` or `bastion.yaml`

`scan` vs `audit` - different inputs, different questions

	`mcp-bastion scan`	`mcp-bastion audit`
Looks at	A tool catalog (`tools.json` / `tools/list` export)	MCP client configs on disk (`mcp.json`, Claude Desktop config, etc.)
Asks	“Is this tool metadata poisoned or drifted?”	“What can agents already reach on this machine?”
Finds	Injection in descriptions, secrets in schemas, homoglyphs, fingerprint drift, weak/unbounded inputSchema shapes	Over-broad tool grants (`*`), standing credentials in `env`, filesystem-server hints
When	Before you ship or attach a server’s tools (CI / pre-deploy)	Before you tighten policy on a laptop or workspace (local hygiene)

They complement each other: audit the host surface, then scan the tools you attach. Neither replaces runtime enforce.

mcp-bastion scan also accepts --skills DIR for offline agent skill-file checks. Dependency CVEs: mcp-bastion osv-refresh then mcp-bastion osv-scan (local DB default; --online opt-in, fail-open).

# 1. Scan a tools/list export (or hand-authored catalog) - client-side, no cloud

mcp-bastion scan examples/fixtures/tools-poisoned.json mcp-bastion fingerprint tools.json -o baseline.json mcp-bastion scan tools.json --baseline baseline.json --format json -o report.json mcp-bastion scan --skills ./skills/

1b. Audit local MCP client configs (what agents can already reach)

mcp-bastion audit --root . mcp-bastion audit --format json -o risk-audit.json --fail-on none

2. Test policy effectiveness

mcp-bastion redteam --config bastion.yaml

3. Enforce at runtime (filesystem path guards when agents can read local files)

merge examples/bastion-filesystem-guards.yaml into bastion.yaml

mcp-bastion validate --config bastion.yaml

mcp-bastion scan - client-side static scanner; no cloud, no ML download

mcp-bastion audit - map the local MCP surface before you enforce; no network, no vault

Schema · Skills · OSV - offline by default; no login server; no phone-home

Feature tour

Dashboard walkthrough

Live security posture + runtime dashboard - local-only, zero infra. mcp-bastion dashboard --demo · Dashboard docs · Older Vimeo walkthrough </

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

MCP-Bastion

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Which apps can use it

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

Robin: AI-Powered Dark Web OSINT

HOL Guard

UniFi Network MCP

README from the maker

MCP-Bastion

Measured proof (offline, reproducible)

Scan → Test → Enforce (no other tool has all three)

1b. Audit local MCP client configs (what agents can already reach)

2. Test policy effectiveness

3. Enforce at runtime (filesystem path guards when agents can read local files)

merge examples/bastion-filesystem-guards.yaml into bastion.yaml