> ## Documentation Index
> Fetch the complete documentation index at: https://www.zinc.com/docs/llms.txt
> Use this file to discover all available pages before exploring further.

# Universal Checkout Skill

> Let AI agents discover, buy, track, and return products with the Zinc API.

The **Universal Checkout Skill** is an [Agent Skill](https://agentskills.io) that lets AI agents shop through the [Zinc API](https://zinc.com) — search for products, place orders, track them, and handle returns across Amazon, Walmart, Target, Best Buy, eBay, and 50+ other US retailers, all through natural language.

<CardGroup cols={3}>
  <Frame caption="Order anything">
    <video src="https://mintcdn.com/zinc/JcZ_00yHjkmfiMBl/videos/agent-skills/claw-demo-1.mp4?fit=max&auto=format&n=JcZ_00yHjkmfiMBl&q=85&s=fc80277ca75010ace7d79133488b883c" controls muted loop data-path="videos/agent-skills/claw-demo-1.mp4" />
  </Frame>

  <Frame caption="Visual search">
    <video src="https://mintcdn.com/zinc/JcZ_00yHjkmfiMBl/videos/agent-skills/claw-demo-2.mp4?fit=max&auto=format&n=JcZ_00yHjkmfiMBl&q=85&s=c887518353c5ac9a75ec1de8a418d184" controls muted loop data-path="videos/agent-skills/claw-demo-2.mp4" />
  </Frame>

  <Frame caption="Handle complex tasks">
    <video src="https://mintcdn.com/zinc/JcZ_00yHjkmfiMBl/videos/agent-skills/claw-demo-3.mp4?fit=max&auto=format&n=JcZ_00yHjkmfiMBl&q=85&s=d8b2c4930218c87505b0e1a38ff6b555" controls muted loop data-path="videos/agent-skills/claw-demo-3.mp4" />
  </Frame>
</CardGroup>

## What is an Agent Skill?

An Agent Skill is a declarative specification (a `SKILL.md` file) that teaches AI agents how to interact with an API. There's no executable code — the skill provides instructions, endpoint definitions, and safety guidelines that the agent follows.

Agent Skills use **progressive disclosure**: at startup only the skill name and description are loaded. The full instructions are read into context only when the agent detects a matching task, keeping your agent fast and focused.

## One skill, or one per retailer

The skill comes in two flavors, both from the same [`zincio/skills`](https://github.com/zincio/skills) catalog:

* **`universal-checkout`** — the full lifecycle across every supported retailer. Install this for general use.
* **Per-retailer skills** (`amazon-checkout`, `walmart-checkout`, `target-checkout`, …) — the same lifecycle retargeted for a single store. Handy when an agent only ever buys from one retailer.

<Info>
  Installing several near-identical per-retailer skills in one agent can make
  skill triggering ambiguous. If you buy across retailers, install
  **`universal-checkout`** rather than stacking retailer skills.
</Info>

## What Can It Do?

| Capability   | Description                                                                              |
| ------------ | ---------------------------------------------------------------------------------------- |
| **Discover** | Search across retailers (`GET /search`) and compare best-price offers (Amazon & Walmart) |
| **Buy**      | Place orders by product URL, with variants, condition filters, and a `max_price` ceiling |
| **Track**    | Check status and the full carrier checkpoint timeline for an order                       |
| **Cancel**   | Cancel an order while it's still queued                                                  |
| **Return**   | Open a return against a placed order and get prepaid label URLs                          |

<Warning>
  Placing an order or opening a return spends real money. The agent always
  confirms with you before submitting.
</Warning>

## Two ways to pay

The skill supports either authentication method — pick based on how the user wants to pay:

| Method                              | When to use                                                                                 |
| ----------------------------------- | ------------------------------------------------------------------------------------------- |
| **API key** (`ZINC_API_KEY`)        | Pre-registered users with a funded Zinc account                                             |
| **MPP** (Machine Payments Protocol) | No Zinc account — pay per request via **Stripe** (cards/wallets) or **Tempo** (stablecoins) |

With MPP, the same `/agent/*` endpoints handle both ordering and metered data calls (\$0.01/call), so an agent can discover and buy with no account at all. Try it without code at [agent.zinc.com](https://agent.zinc.com).

## Supported Platforms

Works with any agent platform that supports the [Agent Skills](https://agentskills.io) standard, including:

* [Claude Code](https://claude.ai/code)
* [OpenClaw](https://openclaw.ai)
* [Cursor](https://cursor.com)
* [Gemini CLI](https://github.com/google-gemini/gemini-cli)
* VS Code, GitHub Copilot, and [many others](https://agentskills.io/home)

## Prerequisites

You'll need **one** of:

1. A **Zinc API key** ([sign up at app.zinc.com](https://app.zinc.com)) with funds deposited, **or**
2. An **MPP payment method** — a funded Tempo wallet key (`TEMPO_PRIVATE_KEY`) or a Stripe payment method. No Zinc account required.

## Next Steps

<CardGroup cols={2}>
  <Card title="Setup" icon="wrench" href="/v2/agent-skills/setup">
    Install and configure the skill for your platform.
  </Card>

  <Card title="Usage Guide" icon="cart-shopping" href="/v2/agent-skills/usage">
    Discover products, place orders, track them, and handle returns.
  </Card>
</CardGroup>