The Check Digits MCP server,
connected in one click.
Catch a mistyped barcode, ISBN, VIN, NPI or LEI before a bad identifier corrupts a record. Connect the official Check Digits MCP server to Claude, ChatGPT, or Cursor through gate — one gateway URL, no config files, security-checked.
Free to start · No credit card · No hosting needed
Add Check Digits to your AI in one minute
Pick your client. Copy, paste, done — or let gate handle sign-ins and policies for you.
claude mcp add --transport http check-digits https://check-digits.toolstop.devRun in your terminal, then restart Claude Code.
Check Digits · https://check-digits.toolstop.dev
What your AI can do with Check Digits
Real prompts you can type the moment it's connected — no setup, no docs to read.
“Use “validate_identifier”: Verify a number when you already know what it is supposed to be. Use this whenever someone gives you a product barcode (GTIN, UPC or EAN), a.”
“Use “identify_format”: Identify a bare number whose type was never recorded. Tests it against every supported format and reports which ones its check digit satisfi.”
“Use “compute_luhn_digit”: Given digits with the final check digit omitted, return the one that completes them. US healthcare NPIs and securities ISINs use the Luhn fo.”
How secure is the Check Digits MCP server?
Every server in the gate directory has to pass the same four checks before your AI can touch it. Here's how Check Digits holds up.
Official endpoint
Operated by Check Digits (toolstop.dev) at its documented MCP endpoint — not a third-party mirror or community re-host.
No sign-in needed
This server only exposes public data — no account and no credentials are involved when you connect.
Scanned before it goes live
gate checks every tool for prompt injection, hidden instructions, data-exfiltration hints, and over-broad permissions before the server is available through your gateway.
Watched for drift
If Check Digits adds or changes tools later, gate re-scans and alerts you — before your AI acts on the change.
Connected in three steps
Connect your gate
Add one gateway URL to Claude, ChatGPT, or any MCP client. One-time setup, about two minutes.
Pick Check Digits
Choose Check Digits in the gate directory. No sign-in needed.
Use it anywhere
Check Digits's tools are live in every AI client you've connected — with rules and logging built in.
Free to start · No credit card · No hosting needed
The actual tools Check Digits exposes
Fetched live from the official endpoint and re-checked daily by gate — not marketing copy.
validate_identifier — Verify a number when you already know what it is supposed to be. Use this whenever someone gives you a product barcode (GTIN, UPC or EAN), a
identify_format — Identify a bare number whose type was never recorded. Tests it against every supported format and reports which ones its check digit satisfi
compute_luhn_digit — Given digits with the final check digit omitted, return the one that completes them. US healthcare NPIs and securities ISINs use the Luhn fo
Who runs the Check Digits MCP server?
The Check Digits MCP server at a glance
https://check-digits.toolstop.devQuestions, answered
Is there an official Check Digits MCP server?
Yes — Check Digits operates its own remote MCP server at check-digits.toolstop.dev. gate connects you to that official endpoint and adds security scanning, per-tool access rules, and an activity log on top.
How do I connect Check Digits to Claude or ChatGPT?
Add gate's gateway URL to your AI client once, then pick Check Digits in the directory. No account or sign-in is needed. From then on, Check Digits's tools are available in every client you've connected to gate.
Do I need to host anything?
No. Check Digits runs the server, and gate is fully managed. You just connect one URL — there's nothing to install, deploy, or maintain.
Is the Check Digits MCP server safe to connect?
It's the vendor's official endpoint, and gate scans its tools for prompt injection and hidden instructions before it goes live, re-checks it whenever it changes, and lets you allow, block, or require approval for every single tool.
Is it free?
Yes — you can get started with gate for free and connect Check Digits in minutes. No credit card required.
Connect more than just Check Digits
Every server below works through the same gateway URL — connect once, add tools anytime.
Squarespace DomainsDesignView →Set up Check Digits in: Claude · Claude Code · ChatGPT · Cursor · VS Code