# 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 2026-09-14).

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

## Facts

- Endpoint: POST https://stable-merch-git-rfs-checkout-nites-merit-systems.vercel.app/api/ucp/checkout-sessions/stablemerch%3Acheckout%3Acmqirx483000akv04fiqi4lh7/complete
- Price: $50/call
- Payment: x402
- Status: unknown
- Last checked: 2026-09-14
- Activations on Zero: 0
- Tags: x402
- Canonical page: https://www.zero.xyz/c/stablemerch-ucp-checkout-session-complete-1543515a
- Structured record (JSON): https://api.zero.xyz/v1/capabilities/cap_Ll-yI8sDAwPVvLD8ZoNsx

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-1543515a -d '<json body>'
```

Example prompt: My StableMerch checkout session cmqirx483000akv04fiqi4lh7 is ready to complete — 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 (status: ready_for_complete) and need to both pay for it and send the Printify production order in a single atomic step. This is specifically for the StableMerch platform's print-on-demand workflow using Printify as the backend fulfillment provider. Prefer this over manual Printify API calls when working within the StableMerch UCP checkout flow.

## Known failure modes

- Checkout session not in ready_for_complete status — payment and submission rejected
- Invalid or expired checkout session ID — 404 or session not found error
- Insufficient USDC balance or payment failure — transaction rejected
- Duplicate completion attempt on already-completed session — idempotency error
- Printify order submission failure — payment may succeed but production submission fails
- Network or Vercel platform timeout — indeterminate state requiring status check

## 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 paid ($50 USDC) and the associated Printify order has been submitted to production for printing and fulfillment. Likely includes order status, Printify order ID, and payment confirmation 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-1543515a/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)