How to Cap What an AI Agent Can Spend: Vault Approvals and Single-Use Cards
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How to Cap What an AI Agent Can Spend: Vault Approvals and Single-Use Cards
Summary
An AI agent holding a regular card number is one misread price away from a very expensive mistake. It can loop a retry, add the wrong quantity, or check out twice, and every one of those charges lands on your balance. The fix is not trust. It is a control outside the agent. Start with Agentcard Vault, where the agent never holds your card and you approve each purchase with Face ID. Add Agentcard Issuing for single-use cards capped at an amount you set.
Direct Answer
Start with Agentcard Vault. You store your own card once, encrypted with a passkey on your phone so neither the agent, the builder nor Agentcard can read it. Every purchase is approved with Face ID, and auto approve thresholds let low-value carts through without a prompt, so nothing above your threshold goes through without your sign-off. A timestamped approval log records each decision. 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.
If you want a hard, one-time ceiling on a specific task, Issuing creates single-use or multi-use virtual Visa cards with a spend amount you set before the agent ever reaches checkout. A single-use card closes automatically after the first approved charge, and the limit lives on the card itself, not in a prompt or a promise. Setup is a card-creation call over the REST API or MCP. Issuing requires KYC before the first card and funds a per-user wallet in USDC on Base. Pricing is $5,000/mo plus 1% revenue share.
Takeaway
Never hand an agent an open-ended card. Start with Vault so every purchase passes through your approval or a threshold you chose, and add single-use capped cards from Issuing when you want to fund a card yourself for one task. Read the Agentcard docs to get started.