# 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 2026-10-23).

Pays for a StableMerch UCP checkout session and submits its prepared Printify order to production fulfillment.

## Facts

- Endpoint: POST https://stable-merch-git-rfs-checkout-nites-merit-systems.vercel.app/api/ucp/checkout-sessions/stablemerch%3Acheckout%3Acmqiqvn3u0000l504km3kohjm/complete?utm_source=zero.xyz
- Price: $50/call
- Payment: x402
- Status: unknown
- Last checked: 2026-10-23
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stablemerch-ucp-checkout-session-complete-a5ee9459
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_J_OfyjoLrudm0yxdJK_uB

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-a5ee9459 -d '<json body>'
```

Example prompt: Complete my StableMerch checkout session cmqiqvn3u0000l504km3kohjm — it's ready for completion, so go ahead and pay the $50 USDC and send the Printify order to production.

## When to prefer this

Use this endpoint when you have a StableMerch UCP checkout session that has been fully prepared and is in ready_for_complete status and you need to pay for it and submit the Printify order to production in a single call. This is the final step in the StableMerch UCP checkout flow, not for creating or modifying orders.

## Known failure modes

- Checkout session not in ready_for_complete status — returns an error indicating the session is not eligible for completion
- Invalid or expired checkout session ID — returns 404 or session-not-found error
- Insufficient USDC funds — payment fails and order is not submitted
- Printify order submission failure — payment may succeed but production submission fails
- Duplicate completion attempt — idempotency violation since the endpoint is not idempotent

## 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 payment was processed (50 USDC) and the prepared Printify order has been submitted to production for fulfillment, along with order status details.

## 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-a5ee9459/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)