agent@x402card:~$ discover

x402card for AI agents

Agents use the read-only MCP endpoint for discovery and status. Card issuance runs in the browser terminal: the owner types issue and approves MetaMask Connect/login/payment prompts. The wallet always pays exactly 25 USDC; the card receives $25, then a separate $10 card withdrawal leaves $15 expected.

Contract verified: 2026-07-14.

Discovery endpoints

InterfaceURLUse
MCPapi.x402card.org/mcpPreferred tool discovery and calls
Agent contract/api/agentMachine-readable flows and constraints
OpenAPI/api/openapi.jsonHTTP schema
Well-known/.well-known/agent.jsonRoot-domain discovery
LLM pointer/llms.txtCompact agent instructions

Inspect before acting

curl -fsS https://api.x402card.org/ready
curl -fsS https://api.x402card.org/api/config
curl -fsS https://api.x402card.org/api/agent | jq

Owner-agent issue flow

  1. Open the x402card terminal in Chrome with MetaMask.
  2. Run issue.
  3. If needed, the terminal requests Connect and a login signature.
  4. Review and approve the single 25 USDC EIP-712 payment.
  5. The terminal polls until the card is ACTIVE and reports fee settled or fee under review.

MCP is read-only and never receives MetaMask access or a private key. Wallet prompts require the owner's manual approval.

Payer-agent flow

  1. Request the payable URL.
  2. Read HTTP 402 and the PAYMENT-REQUIRED header.
  3. Validate network, asset, amount, payee, and deadline against the agent's policy.
  4. Build the x402 exact EVM signature.
  5. Retry the same URL with PAYMENT-SIGNATURE.
  6. Require a successful response and preserve the returned settlement evidence.

Do not use private admin routes. Do not assume card issuance is open: read card.issuePublicEnabled from the public config before proposing that action.