# StableMerch UCP Checkout Session Complete

> StableMerch UCP Checkout Session Complete is a paid API for AI agents from stable-merch-git-rfs-checkout-nites-merit-systems.vercel.app, paid per call via x402, $50/call, status unknown (last checked 2026-09-13).

Completes a ready-for-complete StableMerch UCP checkout session by processing a $50 USDC payment and submitting the prepared Printify order to production.

## Facts

- Endpoint: POST https://stable-merch-git-rfs-checkout-nites-merit-systems.vercel.app/api/ucp/checkout-sessions/stablemerch%3Acheckout%3Acmqimhb4t0000jv04tulgnnqp/complete
- Price: $50/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-13
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stablemerch-ucp-checkout-session-complete-8f925a8d
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_FOx9kM8gZTPwbEZ4EWvlp

Status and success rate cover calls made through Zero and Zero's own probes. Third-party monitors may report differently.

## How to call it through Zero

Zero handles the 402 payment challenge and records the run. With the Zero CLI installed (`npm i -g @zeroxyz/cli`):

```sh
zero fetch --capability stablemerch-ucp-checkout-session-complete-8f925a8d -d '<json body>'
```

Example prompt: My StableMerch checkout session stablemerch:checkout:cmqimhb4t0000jv04tulgnnqp is ready to complete — go ahead and pay the $50 USDC and send that Printify order into production.

## When to prefer this

Use this endpoint when a StableMerch UCP checkout session has been fully prepared and its status is exactly ready_for_complete, and you need to atomically process the $50 USDC payment and push the Printify order into production in a single call. This is the final step in the StableMerch order workflow, not for creating or modifying sessions.

## Known failure modes

- Checkout session not in ready_for_complete status — returns an error if the session is still pending or already completed
- Invalid or unknown checkout session ID — returns a 404 or similar not-found error
- Insufficient USDC balance — payment fails and order is not submitted
- Payment protocol (x402) failure — transaction rejected or timed out
- Printify order submission failure — payment may succeed but order production not triggered

## How this service works

Pay for a StableMerch UCP checkout session and send its prepared Printify order to production. Requires checkout status ready_for_complete.

## Output

Returns a confirmation that the checkout session has been completed, payment of $50 USDC has been processed, and the associated Printify order has been submitted to production for fulfillment.

## Request schema (JSON Schema)

```json
{
 "type": "object",
 "properties": {
  "id": {
   "type": "string",
   "minLength": 1,
   "description": "UCP checkout session ID being completed. AgentCash clients may instead send checkout_session_id."
  },
  "payment": {},
  "checkout_session_id": {
   "type": "string",
   "minLength": 1,
   "description": "AgentCash checkout session ID being completed. UCP clients may instead send id."
  }
 }
}
```

## More

- Live health (JSON, refreshed every minute): https://www.zero.xyz/c/stablemerch-ucp-checkout-session-complete-8f925a8d/health.json
- [Zero catalog index](https://www.zero.xyz/llms.txt)
- [Other services from stable-merch-git-rfs-checkout-nites-merit-systems.vercel.app](https://www.zero.xyz/host/stable-merch-git-rfs-checkout-nites-merit-systems.vercel.app/llms.txt)