GrindFree Agent Security

Name: GrindFree Agent Security
Author: ronin93

by ronin93version 0.1.0i★ –iRuns on your computer

Registry nameio.github.ronin93/grindfree-agent-security

Install

Overview

Description from the maker (original English)

Pay-per-call agent security: prompt-injection screening, URL safety, tool-call policy (x402)

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
UsageiVery new★ –

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
You need to fill in: X402_PRIVATE_KEY

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).
You fill in yourself: X402_PRIVATE_KEY

Values marked secret are keys to your account. Never share them or paste them into a chat.

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": {
    "grindfree-agent-security": {
      "command": "npx",
      "args": [
        "-y",
        "@grindfree/agent-security-mcp"
      ],
      "env": {
        "X402_PRIVATE_KEY": "your-value"
      }
    }
  }
}

Run this in your terminal

claude mcp add grindfree-agent-security --env X402_PRIVATE_KEY=your-value -- npx -y @grindfree/agent-security-mcp

Fill in the empty values before running it.

Open in Cursor

Or copy the settings yourself

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

{
  "mcpServers": {
    "grindfree-agent-security": {
      "command": "npx",
      "args": [
        "-y",
        "@grindfree/agent-security-mcp"
      ],
      "env": {
        "X402_PRIVATE_KEY": "your-value"
      }
    }
  }
}

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": {
    "grindfree-agent-security": {
      "type": "stdio",
      "command": "npx",
      "args": [
        "-y",
        "@grindfree/agent-security-mcp"
      ],
      "env": {
        "X402_PRIVATE_KEY": "your-value"
      }
    }
  }
}

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.

Values you fill in

X402_PRIVATE_KEY secret required env
Caller's own Base USDC EVM private key (0x…). Used only by the local MCP host to settle x402 payments. Never a GrindFree key; never commit this value.

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 9, 2026

✓ Pass
Maker matches the repo
The registry name was verified with the GitHub account ronin93, 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 1004 servers in this category
Published to the registry more recently than 100% of the other 1004 servers in this category
Basic checks equal to or better than 100% of the other 1004 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 GrindFree Agent Security 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?

You need to fill in: X402_PRIVATE_KEY

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 (0.1.0) reached the registry today.

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: VMware NSX Security, SUNGLASSES, KillerSkills

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

VMware NSX Security

VMware NSX security: DFW policies and exclusions, groups, tags, Traceflow, IDPS — 22 MCP tools.

by vmware-skillsVery new↓ 204/wkUpdated today

Runs on your computer

Install

SUNGLASSES

Input firewall for AI agents: scan text and files before they're read. Local, no network by default.

by sunglasses-devEarly↓ 549/wkUpdated today

Runs on your computer

Install

KillerSkills

Security verdicts for agent skills and MCP servers, from sandbox runs, before you install them.

by cyligence-karimGrowing↓ 3.1K/wkUpdated today

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.

GrindFree Agent Security

MCP server + client snippets for GrindFree’s pay-per-call agent security APIs on Base:

Service	Endpoint	Price	What it does
PromptShield	`POST https://promptshield.grindfree.net/v1/screen` · `/v1/clean`	$0.002	Prompt-injection screen + HTML→LLM clean text
CrawlSafe	`POST https://crawlsafe.grindfree.net/v1/check`	$0.002	robots.txt / X-Robots-Tag crawl gate (SSRF-guarded; not malware scanning)
ToolGuard	`POST https://toolguard.grindfree.net/v1/evaluate`	$0.002	Pre-tool-call `allow \	review \	deny` policy gate
CommandGuard	`POST https://commandguard.grindfree.net/v1/command` · `/v1/sql`	$0.001	Shell command + SQL check before execution: `allow \	warn \	block`
MemoryGuard	`POST https://memoryguard.grindfree.net/v1/screen`	$0.002	Screen content before it is written to agent memory (planted instructions, persistence, secrets/PII)
WireShield	`POST https://wireshield.grindfree.net/v1/scan`	$0.002	Outbound leak check on agent output (zero-click image exfil, URL smuggling, canaries, prompt leakage)
DocShield	`POST https://docshield.grindfree.net/v1/scan`	$0.004	Hidden instructions in PDF / DOCX / XLSX / PPTX / HTML / Markdown before the agent reads them

Price: per call in USDC (table above) on Base (eip155:8453) via x402 v2. Wallet: the caller’s Base USDC wallet pays. This repo never ships GrindFree keys.

Contact: rob@grindfree.net · @grindfreelabs

Install / run the MCP server (stdio)

git clone https://github.com/ronin93/grindfree-agent-security.git

cd grindfree-agent-security/mcp-server npm install

Set the caller’s funded Base USDC key in the MCP host env (never commit it):

export X402_PRIVATE_KEY=0xYOUR_BASE_USDC_PRIVATE_KEY

PRIVATE_KEY is also accepted

node src/index.js

Claude Desktop / Cursor-style config:

"mcpServers": { "grindfree-agent-security": { "command": "node", "args": ["/absolute/path/to/grindfree-agent-security/mcp-server/src/index.js"], "env": { "X402_PRIVATE_KEY": "0xYOUR_KEY" } } } }

MCP tools

promptshield_screen / promptshield_clean
crawlsafe_check
toolguard_evaluate — your agent must enforce allow/review/deny before executing the tool; this API cannot stop a bypass
commandguard_command / commandguard_sql — check shell commands and SQL before running them
memoryguard_screen — check content before saving it to long-term memory
wireshield_scan — check agent output before rendering/sending it
docshield_scan — check a local file (path), base64 bytes, or HTML/Markdown for hidden instructions (max 3 MB)
grindfree_discovery — unpaid 402 / discovery probe (no spend)

HTTP snippets (no MCP)

examples/typescript-x402-fetch.ts — official @x402/fetch + @x402/evm
examples/python-x402.py — unpaid probes + paid hook
examples/langchain-tool.py — LangChain-style wrappers

Unpaid challenge (no wallet):

curl -sS -D - -o /tmp/ps402.json -X POST https://promptshield.grindfree.net/v1/screen \

-H 'content-type: application/json' \ -d '{"content":"hi","format":"text"}'

Expect HTTP 402 + PAYMENT-REQUIRED

Honest limits

Heuristic / policy layers — not a full security program.
CrawlSafe is not malware, phishing, or legal/ToS advice.
All guards are deterministic rule packs (no LLM), so they are fast and cheap but can miss novel phrasing; decisions are advisory and your code must enforce block/deny.
DocShield parses structure and text; it does not OCR images or render pages, and legacy .doc/.xls/.ppt return 415 (not charged).
ToolGuard returns a decision; the caller/adapter must enforce it before tool execution. Missing policy → review. Not an exfiltration guarantee.
ToolGuard: always enforce allow|review|deny in your adapter before tool execution (the API cannot stop a bypass). GrindFree has confirmed funded settlement + HTTP 200 delivery on /v1/evaluate via a self-funded Base USDC test; still verify with your own wallet in production.

License

MIT — see LICENSE.

GrindFree Agent Security

Overview

PopNx MCP’s three pillars

What you can do with it

Install

Before you install

Values you fill in

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

VMware NSX Security

SUNGLASSES

KillerSkills

README from the maker

GrindFree Agent Security

Install / run the MCP server (stdio)

PRIVATE_KEY is also accepted

MCP tools

HTTP snippets (no MCP)

Expect HTTP 402 + PAYMENT-REQUIRED

Honest limits

License