@arispay/payagent-mcp

@arispay/payagent-mcp

MCP server that lets AI agents pay for things: call x402-paid APIs (USDC on Base), pay merchants, and manage wallets with spend limits. Works with Claude Desktop, Cursor, Windsurf, or any MCP client. A thin wrapper around the payagent SDK.

Two ways to hold the wallet:

• Local key (zero signup). Set PAYAGENT_PRIVATE_KEY to a funded EOA key. pay_api signs EIP-3009 locally — no ArisPay account, no email. The only guardrail is client-side; use a dedicated low-balance wallet.
• Delegated custody (managed). create_user({ email }) self-provisions an account, a CDP-managed wallet, and credentials in one call. ArisPay enforces per-transaction, daily, and monthly limits server-side; no private key ever lives in this process.

Setup

Add the server to your MCP client config. No environment variables are required — pick a wallet mode later, from inside the chat, or set one of the env options below.

Claude Desktop

Edit ~/Library/Application Support/Claude/claude_desktop_config.json:

{
  "mcpServers": {
    "arispay": {
      "command": "npx",
      "args": ["-y", "@arispay/payagent-mcp"]
    }
  }
}

For the zero-signup mode, add the key to the env block:

      "env": { "PAYAGENT_PRIVATE_KEY": "0x..." }

Cursor

Same server block in .cursor/mcp.json. Windsurf: same pattern in ~/.codeium/windsurf/mcp_config.json.

Cold start, from nothing

• Zero signup: generate a key with npx payagent wallet new, put it in the host config as PAYAGENT_PRIVATE_KEY, send USDC on Base to the printed address. check_wallet shows the deposit address and balance; pay_api pays.
• Managed: ask the agent to run create_user({ email: "[e-mail]" }), then fund_agent({ name }) for a deposit address. Credentials persist to ~/.payagent/config.json and are shared with the payagent CLI.

Environment variables (all optional)

Variable	Description
PAYAGENT_PRIVATE_KEY	Funded EOA key for local self-custody signing (zero-signup mode).
ARISPAY_API_KEY	Developer key — usually unneeded; create_user self-provisions one.
ARISPAY_URL	ArisPay API base URL. Default https://api.arispay.app.
PAYAGENT_MCP_PROFILE	core loads only the 8 pay-URL tools instead of the full surface.
ARISPAY_AGENT_KEY / PAYAGENT_WALLET	Legacy single-agent pair for v2.0.x hosts.

Tools

Wallet-centric core: create_user, create_wallet, list_wallets, fund_wallet, get_balance, pay_merchant.

x402 rail: pay_api (HTTP request with transparent 402 payment — local key or delegated), create_agent, fund_agent, get_balance_agent, list_agents, rename_agent.

Discovery (read-only, free, no key): discover_paid_api (search the paid-API catalog by intent + budget), inspect_paid_api (see a URL's price without paying).

Platform (end-user) tools: create_enduser, attach_card_for_user, set_user_limits, get_user_status. Diagnostic: check_wallet.

Example prompts: "Pay https://api.example.com/premium and show me the data." · "Find a paid API that extracts text from PDFs, under 50 cents." · "Check my wallet."

How it works

• The agent calls pay_api with a URL; the seller answers HTTP 402 with its price.
• With PAYAGENT_PRIVATE_KEY set, payagent signs the EIP-3009 authorization locally. Otherwise ArisPay validates the request against the agent's delegation limits and signs via Coinbase CDP.
• payagent retries with the signed payment header; the seller's facilitator settles USDC on-chain.

In delegated mode, no private key lives in this process and payments that breach the delegation are rejected before any on-chain action. In local mode, the key is yours and stays in your process.

Install

npm install @arispay/payagent-mcp

Or invoke directly via npx @arispay/payagent-mcp from an MCP client config — no pre-install required. npx buyforme-mcp is the same server under the consumer brand.

Related

• payagent — the SDK + CLI for programmatic use
• facilitator.arispay.app — ArisPay's open x402 facilitator (USDC + EURC on Base), where paid 402s settle
• x402 protocol — HTTP 402 payment standard

License

MIT