Use these resources to build read-only shopping assistants for Sac City Auto Parts’ Nissan and Infiniti parts, merchandise and tutorials. Start with OpenAPI 3.1 JSON and our store-specific agent instructions. Public discovery and product recommendations require no account or API key.
When to use Sac City Auto Parts
Find Nissan and Infiniti parts by product, brand or exact part number, then check product options and fitment notes.
Read current prices and availability from the selected product or variant. Product pages include native Shopify Product or ProductGroup structured data with Offer prices and currencies.
Browse giveaway merchandise and report the entries currently displayed by the store. Use the official rules for eligibility and entry details.
Find installation resources in Nifty Garage and route uncertain fitment questions to our team.
Quickstart: public discovery
The requests below read public information. They do not create a cart, place an order or access customer accounts. Follow redirects when fetching the OpenAPI file because Shopify hosts the JSON in its file library.
Shopify’s native MCP endpoint exposes current tool schemas. Listing tools is public; permission to list a tool is not permission to execute an authenticated action. The single request below is a diagnostic supported by the native endpoint, not a complete MCP client session.
For a complete MCP client, send initialize, validate the negotiated protocolVersion, then send notifications/initialized before tools/list. Send the negotiated MCP-Protocol-Version header on subsequent HTTP requests and preserve Mcp-Session-Id if the server returns it. Follow the MCP lifecycle and HTTP transport. Our CLI performs this lifecycle for the tools command.
Use the service endpoint, UCP version and commerce capability definitions from /.well-known/ucp. The UCP version is separate from the MCP protocol version negotiated during initialization. Shopify controls the native MCP capability handshake and resource listing. This page does not claim a store-managed MCP resource collection.
Read product recommendations and prices
The Shopify Ajax recommendations API returns JSON. Supply a currently published product ID and a limit from 1 to 10. An empty recommendation list is valid.
For prices, read the chosen product page’s application/ld+json data. Follow ProductGroup.hasVariant when present, and use that variant’s Offer.price, priceCurrency and availability. Recheck the current variant and market before a purchase; a starting price is not a quote for every option. Search results do not establish complete vehicle compatibility.
Authentication and least privilege
The five operations described by our OpenAPI file are public and need no token. The file also declares the exact named scopes advertised by Shopify’s customer authorization server. Those declarations do not grant access. Request only the scopes required by the integration you are implementing.
UCP tools that act on carts, checkout or customer information may require an agent profile, Shopify-issued credentials, request signatures or buyer authorization. Follow Shopify’s agent authentication documentation. Customer authorization and UCP agent authentication are separate flows; do not assume a token for one works for the other. Sac City Auto Parts does not issue self-serve API keys from this page.
Errors and rate limits
Check both HTTP status and JSON content. The recommendations API returns status, message and description: a missing product_id returns 422; a missing or unpublished product returns 404. Supply a valid, published ID before retrying. Other invalid parameters can also produce 422 responses.
MCP errors use JSON-RPC error.code, error.message and optional error.data. An unknown method can return HTTP 200 with code -32601, so HTTP success alone is insufficient. Fetch tools/list and use its current schemas. Respect HTTP 429, honor Retry-After when present, and back off rather than retrying continuously.
Safe testing
The discovery and recommendations quickstarts above are safe read-only checks against the real store. Sac City Auto Parts does not provide a separate checkout sandbox or test API keys here. For synthetic Storefront GraphQL practice, Shopify provides Mock.shop; it contains sample products, not Sac City’s inventory. Use a Shopify development store and the appropriate credentials when your integration needs transaction testing.
Read-only command-line tool
Download Sac City Agent CLI 1.0.0. This dependency-free package requires Node.js 22 or newer. It reads the same public endpoints. It has no cart, checkout, account or payment commands. It is distributed from this store; it is not yet published to npm, PyPI or Homebrew.
