Validates an agent's x402 v1 client implementation against a TunnelMind
surface end-to-end. Two operating modes:
- `mode: "demo"` — HMAC over a nonce against a publicly-published secret.
Does not move USDC. Smoke proves the WIRE works, not money movement.
- `mode: "x402"` — real Coinbase facilitator dispatch (gated on
operator wallet provisioning; currently returns "facilitator not configured").
Without an `X-PAYMENT` header, the endpoint returns HTTP 402 with a standards-
compliant `accepts[]` array (USDC on Base, $0.001).
With a valid `X-PAYMENT` header (base64-encoded payment payload), echoes the
request body and returns an `X-PAYMENT-RESPONSE` settlement header.
Use this tool when:
- You are validating your agent's x402 v1 client implementation against a real
public endpoint.
- You want to demonstrate the full 402 → retry → settle wire end-to-end.
Do NOT use this tool when:
- You need a real paid operation — no TunnelMind production endpoint is gated
behind x402 yet.
Inputs:
- `X-PAYMENT` (header, optional): base64(JSON) per the x402 v1 spec. Without it,
a 402 challenge is returned.
- Request body (optional): any JSON object to be echoed back on successful payment.
Returns:
- On no header: HTTP 402 + `{ x402Version, accepts: [...] }`.
- On valid payment: HTTP 200 + `{ ok: true, data: { echoed, paid_micro_usdc, x402 } }`
and an `X-PAYMENT-RESPONSE` header carrying the settlement record.
- On invalid payment: HTTP 402 + `{ error: "invalid payment", reason }`.
Discovery:
- `https://tunnelmind.ai/.well-known/x402.json` carries the public demo secret
and the HMAC construction recipe.
Cost:
- Free in demo mode (no USDC moved). $0.001 USDC in real-mode (when activated).
Latency:
- Typical <100ms (demo mode); real mode is bounded by facilitator latency.