Is BigCommerce agent-ready? Defaults and what to fix

BigCommerce’s Stencil themes render product pages on the server, and the Cornerstone theme ships Product JSON-LD. Richer structured data and llms.txt are not included, and the agentic commerce protocols layer is in early access. This guide maps each check in the agent-ready ecommerce score to what a stock BigCommerce store gives you.

What does BigCommerce give AI agents by default?

On Stencil, Handlebars templates run on the server and produce the HTML that shoppers and agents receive (Stencil tech stack). Cornerstone outputs Product JSON-LD from templates/components/products/schema.html (Cornerstone source). The XML sitemap lives at /xmlsitemap.php (BigCommerce sitemaps). For agentic checkout, BigCommerce runs “Agentic Checkout with Google UCP” as an early-access program through Commerce AI Labs, configured in Channel Manager (BigCommerce).

“Theme” in the tables below means the result depends on your theme. The defaults describe current Cornerstone.

Access

Check	Default on BigCommerce	What to do
AI agents not blocked	Depends on any CDN or bot rules you add	Allow AI user agents in every layer in front of the store.
robots.txt	System defaults, merged with your edits	Check your edits for AI bot Disallow rules.
No CAPTCHA	Depends on your apps and scripts	Keep CAPTCHA off product pages and the cart.
No content gates	Depends on your apps	Don’t swap the page HTML for a gate.

Product data

Check	Default on BigCommerce	What to do
Product facts in HTML	Rendered on the server by Stencil	None for Stencil
Product JSON-LD	Cornerstone: Product with SKU, MPN, GTIN, brand, Offer and availability	Update older themes. Fill in GTIN and brand.
Variants modeled	Single Product, no ProductGroup	Extend schema.html.
Return and shipping data	Not in Cornerstone	Add MerchantReturnPolicy and OfferShippingDetails.
OpenGraph price tags	Theme	Check your theme’s head for og: price tags.

Discovery

Check	Default on BigCommerce	What to do
Sitemap	/xmlsitemap.php on Stencil, /sitemap.xml on Catalyst	Make sure robots.txt lists it.
Canonical and status codes	Theme	Keep a self-referencing canonical on product pages.
Performance	Theme and scripts	Trim third-party scripts.
Markdown alternative	Not documented	Low weight. You can skip it.
llms.txt / agents.md	Not documented	Add one if you can serve a root file (see below).

Operability

Check	Default on BigCommerce	What to do
Add-to-cart in a form	Cornerstone: <form method="post" action="{{product.cart_url}}"> with <input type="submit">	Keep the form if you customize the product view.
Variant controls	Cornerstone: radio inputs with labels, including swatches, plus <select>	None for Cornerstone
Accessible names	Theme	Give icon-only buttons a name.
Site search	/search.php?search_query=term	None
Policy links	You create the policy pages	Create return and shipping pages and link them in the footer.
Semantic structure	Theme	One h1, landmarks and alt text.

Agentic commerce

Check	Default on BigCommerce	What to do
UCP profile	Depends on enrollment in the Google UCP early-access program	Request early access through Commerce AI Labs.
Live agent endpoint	Comes with the UCP profile, if one is served	Skipped without a profile
Checkout permalinks	/cart.php?action=add&product_id=ID exists	Declare a UCP permalink capability for credit.
OAuth discovery	Not documented for storefronts	Needed only with an agent endpoint
Bonus checks (WebMCP, A2A, AI Catalog, API catalog, rel="ucp")	Not documented	Optional

How do I fix a BigCommerce store for AI agents, in priority order?

1. Check robots.txt and bot rules

Edit robots.txt in Settings → Website → Search Engine Robots. BigCommerce merges your rules with its system defaults (BigCommerce robots.txt). Don’t disallow AI search bots or user-initiated agents. Blocking training crawlers is your choice and isn’t penalized. If you run a CDN or WAF in front of the store, allow the same bots there. The AI user agents guide lists them.

2. Update the theme’s Product JSON-LD

Cornerstone replaced its microdata with a single JSON-LD block in 2021 (PR #2138). If your theme is older, or was forked before then, pull in templates/components/products/schema.html. Then fill in GTIN, MPN and brand on each product so those fields aren’t empty.

3. Add return, shipping and variant data

Cornerstone’s schema outputs one Offer and nothing about returns or shipping. Return and shipping data is the most common fail across all the stores we calibrated against. Add a MerchantReturnPolicy and OfferShippingDetails. Google accepts them at Organization level (return policy), so one block in your base layout covers the catalog. For products with options, extend schema.html into a ProductGroup with hasVariant entries that each carry their own SKU (product variants).

4. Link policy pages sitewide

Create web pages for returns, shipping, terms, privacy and contact. Then make sure your theme’s footer links to all five on every page.

5. Turn on UCP when it’s available to you

BigCommerce’s UCP path is the Google agentic checkout program. It’s in early access, and the article says timing is “subject to Google approval”. It needs complete Merchant Center data: titles, GTINs, price, availability, shipping, a returns policy and a support contact (BigCommerce). On Catalyst, version 1.12.0 proxies /.well-known/ucp and /api/ucp/* to BigCommerce, so agents find UCP on your own domain (Catalyst 1.12.0 changelog). If you customized proxy.ts, keep withUcpProxy first in composeProxies.

6. Give agents a cart link pattern

BigCommerce supports add-to-cart URLs such as /cart.php?action=add&product_id=123&qty=1, and action=buy sends the shopper straight to checkout. Agents can’t discover these on their own, so document the pattern in an llms.txt if you can serve one. The scan only gives full credit for a UCP permalink capability.

Scan your store

Run the free scan on your store URL to see which of these checks your theme passes. Every failing check comes with a fix prompt you can copy. Terms are defined in the glossary.

Sources

• BigCommerce: Stencil tech stack
• Cornerstone schema.html
• Cornerstone PR #2138: microdata to JSON-LD
• BigCommerce: sitemaps
• BigCommerce: Catalyst sitemap
• BigCommerce: robots.txt file
• BigCommerce: add-to-cart URLs
• BigCommerce: Google agentic checkout
• BigCommerce changelog: Catalyst 1.12.0 UCP proxy
• BigCommerce: checkUcpProgram mutation
• Google: return policy structured data
• Google: product variants structured data
• UCP specification