Skill

ucp-checkout-mcp

Implements UCP Checkout as 5 MCP tools (create/get/update/complete/cancel) for AI agents. Guides building commerce MCP servers or Shopify integration.

Node

Python

api-development

backend

Install

npx claudepluginhub orcaqubits/agentic-commerce-skills-plugins --plugin ucp-agentic-commerce

Tool Access

This skill is limited to using the following tools:

ReadWriteEditBashGrepGlobWebSearchWebFetch

Preview

**Fetch live spec**: Web-search `site:ucp.dev specification checkout-mcp` and fetch the page for exact tool definitions, JSON-RPC envelope format, and `_meta` requirements.

SKILL.md

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Stats

Parent Repo Stars14

Parent Repo Forks9

Last CommitMar 9, 2026

Actions

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UCP Checkout — MCP Binding

Before writing code

Fetch live spec: Web-search site:ucp.dev specification checkout-mcp and fetch the page for exact tool definitions, JSON-RPC envelope format, and _meta requirements.

For Shopify's production MCP server, fetch https://shopify.dev/docs/agents/checkout/mcp for auth flow and endpoint details.

Conceptual Architecture

How MCP Maps to UCP

UCP over MCP is a 1:1 mapping of checkout operations to MCP tools using JSON-RPC 2.0. The same data model as REST, different envelope.

Five MCP Tools

MCP Tool Name	Maps To	Key Inputs
`create_checkout`	POST /checkout-sessions	checkout object + idempotency_key
`get_checkout`	GET /checkout-sessions/{id}	id
`update_checkout`	PUT /checkout-sessions/{id}	id + checkout object
`complete_checkout`	POST .../complete	id + payment_data + idempotency_key
`cancel_checkout`	POST .../cancel	id + idempotency_key

Meta Requirements

Every MCP tool call MUST include _meta.ucp.profile pointing to the platform's UCP profile URI. This replaces the UCP-Agent HTTP header from the REST binding.

Error Mapping

UCP errors embed inside JSON-RPC 2.0 error responses:

JSON-RPC error.code: -32603 (Internal Error)
JSON-RPC error.data: Contains an errors[] array, where each error has code, message, severity, and details fields

When to Use MCP Binding

You're building a merchant MCP server that AI agents (Claude, Gemini, etc.) call via tool use
You're integrating with an existing MCP server (e.g., Shopify's)
You want AI agents to autonomously browse and purchase without REST client code

Implementation Guidance

Building a Business MCP Server:

Implement the 5 tools using your MCP framework (e.g., @modelcontextprotocol/sdk for Node, mcp for Python)
Extract _meta.ucp.profile from every tool call for negotiation
Return checkout objects as JSON in the MCP tool result
Return errors using JSON-RPC error format with UCP data payload
Implement idempotency on create and complete tools

Connecting to an existing MCP server (e.g., Shopify):

Authenticate (Shopify uses OAuth2 client_credentials for access tokens)
Connect to the MCP endpoint
Call tools with proper _meta.ucp.profile and checkout payloads
Parse tool results for checkout status and messages

Shopify MCP Integration

Shopify provides a production MCP server for UCP checkout. Before implementing:

Fetch https://shopify.dev/docs/agents/checkout/mcp for the latest auth flow, endpoint URL format, and error codes
Authentication uses POST https://api.shopify.com/auth/access_token with client credentials
MCP endpoint is POST https://{shop-domain}/api/ucp/mcp