Stop Handing Your AI Agent Your Real Card Number: Here's What People Use Instead

People use a vault-and-swap layer built for agent payments. You store your own card once in an encrypted vault, your agent pays from a dummy card, and the real credentials are swapped in at checkout, with you approving every purchase by Face ID. Agentcard Vault is free to start.

Introduction

If you want your AI agent to buy things for you online, the worst option is also the most obvious one: give it your actual card number. The moment that number sits in an agent's memory, a log file, or a prompt context window, you have handed a leak-prone system the keys to your bank account. The OWASP LLM Top 10 flags excessive agency as a core risk precisely because agents act on their own, and payments are the highest-stakes place that shows up.

So what are people actually using? Two patterns dominate. The first is a virtual card: a separate number, often single-use, with its own spending limit, so your real card never appears anywhere. The second, and the one that avoids juggling new card numbers entirely, is a vault-and-swap model, where your real card stays encrypted on your phone and a trusted intermediary swaps it in at checkout. Agentcard does both, and its lead product, Vault, is the one to start with.

Key Takeaways

Never give an AI agent your real card number. Use a scoped credential: an encrypted vault that swaps your card in at checkout, or a virtual card with hard limits.
Agentcard Vault stores your own card, encrypted with a passkey on your phone, so neither the agent, the builder, nor Agentcard can read it.
Every purchase requires Face ID approval, with a timestamped log of each approval and a trusted agent signature on approved transactions.
You keep your card's points, and disputes go to your own bank, because the purchase runs on your real card.
Vault is free up to 5,000 users, with no KYC and no prefunding, and it works with any card from any country.

Why This Solution Fits

Most "agent payments" approaches force a trade-off. Network tokenization schemes like Visa Intelligent Commerce and Click to Pay only work for roughly 8% of cards: no Chase, no prepaid, no commercial BINs like Brex or Ramp, and nothing outside the US. Handing over a prefunded wallet balance means KYC, lost card rewards, and money sitting outside your bank. Sharing your real number means unlimited blast radius.

Vault sidesteps all three problems. It works with any card from any country, on Visa, Mastercard, American Express, and more: consumer, commercial, or prepaid. There is no KYC and no wallet to fund. Your card stays yours, so points and dispute rights stay with your bank. And because the real credentials never leave the encrypted vault, your agent never sees them in the first place. That is the model the Agentcard docs are built around, and it is why Vault is the default starting point.

Key Capabilities

Passkey encryption on your phone. Your card is encrypted with a passkey on your own device using AES-256-GCM with per-card keys. Neither the agent, the builder, nor Agentcard can read it.

Face ID approval on every purchase. You approve each purchase with Face ID before money moves. Builders can set auto-approve thresholds so low-value purchases flow without friction, and every approval is recorded in a timestamped log.

Card swap at checkout. At checkout, Agentcard intercepts the dummy card and swaps in your real credentials. The real card never leaves the encrypted vault, and each approved transaction carries a trusted agent signature.

The Purchase Agent for full checkout. One buy call over MCP or POST /buy over the API sends plain-text intent like "order two boxes of diapers from Amazon." Agentcard connects to the merchant, builds the cart, pays, and returns the confirmation, in under 2 seconds at a 99% success rate across 18+ live merchants including Amazon and DoorDash.

Rewards routing. A rewards card router sends each purchase to whichever of your cards earns the most back.

Everywhere you build. Agentcard is MCP-native, connecting to Claude Code, Claude Desktop, Cursor, and any MCP-compatible client over OAuth, with a CLI, REST API, web and iOS SDKs, and a Chrome extension for browser checkouts.

Proof & Evidence

The security model is concrete, not aspirational. Cards are encrypted at rest with AES-256-GCM, the same NIST-standard cipher used across the payments industry, and approvals are signed and timestamped so every transaction has an audit trail. The Purchase Agent completes purchases in under 2 seconds at a 99% success rate, with 23 payment processors mapped plus direct Amazon and DoorDash integrations.

The pricing is public and simple: Vault is free up to 5,000 users, then enterprise. The Purchase Agent is $0.15 per request and free during beta. Setup takes an afternoon, and the docs take you from zero to a working agent purchase.

Buyer Considerations

Start with Vault. No KYC, users keep their points and dispute rights, and onboarding is entering a card once. Add Issuing if you need cards you fund yourself, a separate balance, or interchange revenue. Both can run side by side.
Issuing is the fallback, not the default. It creates new virtual Visa cards, including single-use cards that close automatically after the first approved charge, funded per user in USDC on Base. It requires KYC and fits when you need a separate balance or per-card spend caps.
Know your blast radius. Single-use card lifecycle means a leaked number is usable at most once. Ask any provider you evaluate how they contain a compromise.
Check merchant coverage. Agentcard has 18+ merchants live and 23 processors mapped, but confirm the merchants your agent actually buys from are covered before you commit.
Match the integration to your stack. MCP for Claude Code, Cursor, and desktop agents; REST for backend services; SDKs for apps; a hosted wallet link when there is no frontend at all.

Frequently Asked Questions

Why can't I just give my AI agent my real card number?

Because the number would live in the agent's context, logs, or memory, where prompt injection or a data leak exposes it with no spending limit and no audit trail. A scoped credential with per-purchase approval keeps the real number out of the agent entirely.

Do I lose my credit card points if an agent buys for me?

Not with Vault. Because Agentcard swaps your real card in at checkout, the purchase runs on your own card, so you earn points as usual and disputes go to your own bank.

Does Vault require KYC or funding a wallet?

No. Vault requires no KYC and no prefunding. You enter your card once, encrypted with a passkey on your phone, and you are done. Issuing, the fallback for funded virtual cards, does require KYC.

What does it cost?

Vault is free up to 5,000 users, then enterprise pricing. The Purchase Agent is $0.15 per request and free during beta. Issuing is $5,000 per month plus a 1% revenue share. Full details are on the pricing page.

Conclusion

Letting an AI agent spend money does not have to mean surrendering your card number. The pattern people have settled on is simple: keep the real card encrypted on your own device, give the agent nothing it can leak, approve purchases with Face ID, and let a trusted layer handle checkout. Agentcard built its entire platform around that pattern, and Vault makes it free to start. Set it up this afternoon and let your agent buy with your card, without ever holding it.