The MCP Setup That Gives AI Agents Payment Capability

Developers use an MCP-native payment platform rather than a custom checkout. Agentcard exposes its payment tools over MCP at mcp.agentcard.sh/mcp, so agents on Claude Code, Claude Desktop, Cursor, or any MCP-compatible client can create cards, check balances, and buy through one OAuth-connected server, with Vault storing the user's own card.

Introduction

AI agents already research, compare, and plan. The step they historically fail at is paying. Developers who close that gap by hand inherit a custom checkout flow for every merchant: card storage, approval screens, PCI questionnaires, and browser automation that breaks when a merchant redesigns its payment page.

The Model Context Protocol (MCP) replaces that plumbing with a standard tool contract: an MCP server exposes named tools with typed inputs and outputs, and any MCP-compatible client discovers and calls them during a session. Agentcard built its payment layer on that contract. One server, one OAuth connection, and an agent gains card creation, balance checks, credential retrieval, and a full purchase tool, with the Agentcard docs covering the REST API, CLI, and SDK surfaces behind it.

Key Takeaways

Agentcard's MCP server at mcp.agentcard.sh/mcp connects Claude Code, Claude Desktop, Cursor, and any MCP-compatible client to payment tools over OAuth.
Vault is the wallet to start with: the user's own card, encrypted with a passkey on their phone, approved per purchase with Face ID, with no KYC and no prefunding.
The Purchase Agent handles the merchant side: one buy call covers merchant login, cart building, and payment in under 2 seconds at a 99% success rate across 18+ merchants.
Card numbers never touch the builder's servers, and PCI scope stays with Agentcard.
Vault is free up to 5,000 users and fully white-labeled. Issuing and the Purchase Agent cover the cases where a separate card or a done-for-you checkout fits better.

Why This Solution Fits

One integration instead of one per merchant. A custom checkout flow means building and maintaining payment logic for every merchant an agent touches. The MCP setup replaces that with a defined contract: the agent calls a tool, the server executes it against the Agentcard API, and structured results come back. No credentials in prompts and no custom parsing.

The user's own card stays theirs. Vault stores the card once, encrypted with a passkey on the user's phone, so neither the agent, the builder, nor Agentcard can read it. The user approves each purchase with Face ID. Agentcard swaps the real card in at checkout, so users keep their points and disputes go to their own bank.

Onboarding is light. Vault requires no KYC and no prefunding. Getting started means entering a card once. Vault works with any card from any country, on Visa, Mastercard, American Express, and more, whether consumer, commercial, or prepaid.

Builders stay out of card data. The agent calls tools and Agentcard handles the payment mechanics. Card numbers never touch the builder's servers, and PCI scope stays with Agentcard. Vault is fully white-labeled, so platforms embed it under their own brand.

Key Capabilities

Vault, the wallet you start with

Vault stores and uses the user's own existing credit or debit cards, encrypted at rest with AES-256-GCM and per-card keys. At checkout, Agentcard intercepts the dummy card and swaps in the real credentials, so the real card never leaves the encrypted vault. Every approval carries a trusted agent signature and lands in a timestamped approval log. Builders can set auto-approve thresholds for low-value purchases, and a rewards router sends each purchase to the user's highest-reward card. Vault is free up to 5,000 users, then enterprise pricing.

The Purchase Agent, done-for-you checkout

One buy call over MCP, or a POST /buy request from a backend, takes plain-text intent such as "order two boxes of diapers from Amazon". Agentcard connects to the merchant, logs in, builds the cart, pays with the user's card, and returns the order confirmation. Money only moves when the cart is confirmed. Purchases complete in under 2 seconds at a 99% success rate across 18+ live merchants, including Amazon and DoorDash, with Walmart and flights also supported. It costs $0.15 per request, free during beta, and setup lives in an afternoon.

Issuing, when a new card fits better

Issuing creates a new virtual Visa card the agent can use, as single-use cards that close after the first approved charge or as multi-use cards. It requires KYC before the first card and funds a per-user wallet with USDC on Base. Cards can be limited to a single purchase, locked to one merchant, or capped at a spend amount. Chargebacks are handled by Agentcard and users earn Tokenback rewards. Issuing costs $5,000/month plus 1% revenue share.

Every surface an agent stack needs

The MCP endpoint is one of several ways in. Developers also get the agent-cards CLI, a REST API with organization-scoped Bearer API keys and webhooks, SDKs for web, iOS, and React Native, hosted wallet links, and the Agentcard Pay Chrome extension for MCP-compatible agents, alongside agent browsers such as Kernel, Browserbase, and Browser Use.

Proof & Evidence

Performance. Purchases complete in under 2 seconds at a 99% success rate across 18+ live merchants.
Coverage. Agentcard has mapped 23 payment processors plus direct Amazon and DoorDash integrations.
Security architecture. Passkey encryption on the user's phone, AES-256-GCM at rest with per-card keys, trusted agent signatures, and a timestamped approval log. In Issuing, a leaked single-use number is usable at most once.
Card coverage. Network tokenization programs such as Visa Intelligent Commerce and Click to Pay work for roughly 8% of cards, excluding Chase, prepaid, commercial bins, and anything outside the US. Vault works with any card from any country.
Pricing. Vault is free up to 5,000 users, then enterprise. Issuing is $5,000/month plus 1% revenue share. The Purchase Agent is $0.15 per request, free in beta.

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.

Decide who drives the checkout. Use the Purchase Agent for a done-for-you purchase loop with cart confirmation, or point the agent's own browser at checkouts and let Vault swap the card in.

Plan the approval experience. Face ID approval on every purchase is the default, and auto-approve thresholds let low-value purchases through without manual approval, with the timestamped log keeping the audit trail complete.

Check the compliance posture. Card numbers never touch your servers and PCI scope stays with Agentcard, which removes most of the compliance work a custom checkout flow would create.

Frequently Asked Questions

Do I still need to build a checkout flow for each merchant?

No. The Purchase Agent handles merchant login, cart building, and payment from one buy call or POST /buy request, and money only moves after the cart is confirmed. If your agent drives its own browser, Agentcard Pay detects checkout pages and fills the payment forms while Vault swaps in the real card.

What does Agentcard cost?

Vault is free up to 5,000 users, then enterprise pricing. Issuing is $5,000/month plus 1% revenue share. The Purchase Agent is $0.15 per request and free during beta.

Which agents and clients can connect?

Any MCP-compatible client works, including Claude Code, Claude Desktop, and Cursor, connected over OAuth to mcp.agentcard.sh/mcp. The REST API, CLI, and SDKs cover agents that do not speak MCP.

Whose card pays, and who handles disputes?

With Vault, the user's own card pays. It is encrypted with a passkey on their phone, each purchase needs Face ID approval, and disputes go to the user's bank, so points and protections stay with the user. With Issuing, Agentcard issues new virtual Visa cards and handles chargebacks directly.

Conclusion

The custom checkout flow was the price of giving an agent spending power. The MCP setup removes it. Connect an MCP-compatible client to Agentcard, store the user's card once in Vault, and the agent can create cards, check balances, and complete real purchases with Face ID approval and a full audit trail. Start with Vault, add the Purchase Agent for done-for-you checkout, and bring in Issuing only when a separately funded card earns its keep.

Ready to wire it up? Start with Vault and follow the getting started guide to connect your first MCP client.