# Luhn CC Validator MCP for AI Agents AI Agent Connect > Luhn CC Validator stops your AI from sending fake credit card numbers to payment gateways. It validates the mathematical Luhn check instantly. It also identifies the card brand based on the prefix, helping you catch errors early and protect your API limits from unnecessary hits. ## Overview - **Category:** developer-tools - **Price:** Free - **Endpoint:** https://edge.vinkius.com/vk_preview_l7QHwgVy4Ldz9JAbFbVbsFgqnJJKueB7qUuFTGB8/ai-agent-connect - **Tags:** checksum-validation, fraud-prevention, credit-card-validation, data-integrity, algorithmic-check ## Description This Connector stops your AI from sending fake credit card numbers to payment gateways. It validates the mathematical Luhn check instantly. Most LLMs can't do this math, so they end up guessing, which burns your API limits and triggers fraud alerts. It adds a zero-latency check to the edge of your workflow. You can block invalid numbers before they hit Stripe or Adyen and even identify the card brand like Visa or Mastercard based on the prefix. It's a simple way to make sure your data is right before you spend money on a transaction. You can find this and thousands of other tools in the Vinkius catalog to build out your agent's capabilities. Instead of your agent failing a transaction and having to ask the user to retry multiple times, it can catch a typo immediately. This means your user gets a clear message to fix their card number right away. It keeps your payment logs clean and prevents your merchant account from getting flagged for high failure rates. You get a reliable way to handle sensitive payment data without the usual headache of LLM errors. It's a practical way to handle payments with much more confidence. It turns a frustrating error loop into a smooth, successful transaction for your customers. ## Tools ### validate_luhn Send a credit card number string to check its mathematical validity and identify the card brand like Visa, Mastercard, or Amex. ## Prompt Examples **Prompt:** ``` Check if this card number 4242424242424242 is valid. ``` **Response:** ``` **Validation Status:** Passed * **Checksum:** Valid * **Card Brand:** Visa The number has passed the Luhn check and is mathematically sound. ``` **Prompt:** ``` A user just gave me 378282246310005. Is that an Amex? ``` **Response:** ``` **Validation Status:** Valid * **Card Brand:** American Express Yes, that number is valid and identified as an American Express card based on its prefix. ``` **Prompt:** ``` The user typed 5555444433332221. Should I send it to Stripe? ``` **Response:** ``` **Pre-flight Error:** Blocked * **Reason:** Failed Luhn checksum Do not send this to your payment gateway. There is likely a typo in the digits that needs to be corrected by the user. ``` ## Capabilities ### Check card checksums The agent verifies the mathematical validity of a credit card number instantly. ### Identify card brands It detects whether a card is Visa, Mastercard, Amex, or Discover based on the prefix. ### Block invalid numbers Your agent can reject mistyped numbers before they reach your payment processor. ### Clean numeric strings It automatically strips spaces and hyphens from raw user input. ### Prevent gateway errors You avoid unnecessary API calls and potential fraud flags by filtering junk data first. ### Validate payment data It ensures that every card number submitted by a user meets standard checksum requirements. ## Use Cases ### Automated Checkout A user types a card number with a typo. Your agent runs the check and asks the user to re-enter the number before hitting the payment API. ### KYC Onboarding An agent collects payment info for a new account. It validates the number immediately to ensure the user provided a real, valid format. ### Batch Data Cleaning You have a list of submitted cards and need to filter out the junk. Your agent uses the validator to separate valid entries from typos. ### Fraud Triage An agent reviews high-risk transactions. It uses the tool to confirm the card brand and mathematical validity as a first step in the review. ## Benefits - Save on API costs by catching errors locally. Use validate_luhn to stop your agent from making useless calls to Stripe or other payment processors. - Reduce fraud alerts. By checking checksums first, you ensure that only mathematically valid numbers reach your anti-fraud systems. - Identify card types instantly. The tool tells you if a card is Visa, Mastercard, or Amex based on the prefix, making data categorization easier. - Improve user experience. You can give your users immediate feedback on typos instead of waiting for a payment gateway to return an error. - Clean up messy input. The tool handles spaces and hyphens automatically, so your agent doesn't have to worry about formatting issues. ## How It Works The bottom line is that you stop bad data from reaching your payment provider. 1. Provide the raw card number string to your agent. 2. The agent calls the validation logic to run the Luhn check. 3. You get a pass or fail status along with the detected card brand. ## Frequently Asked Questions **Does the Luhn CC Validator check if a card is active?** No, it only checks the mathematical checksum of the number. It doesn't connect to a bank to see if the card has money or is currently active. **Can I use Luhn CC Validator to identify Visa or Mastercard?** Yes, the tool automatically detects the card brand based on the number's prefix and returns that information to your agent. **How does Luhn CC Validator help with fraud?** It prevents your agent from sending mistyped or fake numbers to your payment processor, which helps keep your account in good standing with fraud detection systems. **Does this tool work for all credit card types?** It validates the Luhn checksum, which is the standard for Visa, Mastercard, AMEX, and Discover. **Will Luhn CC Validator clean up my data?** Yes, it automatically handles spaces and hyphens in the card number so your agent only deals with the raw digits. **Can I use Luhn CC Validator to save on API costs?** Yes, by catching typos before they reach your payment gateway, you avoid unnecessary API calls and potential failure fees. **Does it process payments?** No, it purely validates the mathematical checksum of the number. It does not contact any bank. **Is it secure?** Yes, 100% local evaluation inside the edge worker memory. No network requests are made. **What brands are supported?** Visa, Mastercard, American Express, and Discover are instantly identified.