ARC INDEX · SUPPLEMENTS

Four Sigmatic

Name: Four Sigmatic on the ARC Index
Creator: ARC

WHAT GROK TOLD A SHOPPER

One AI model's read-back recommended this.

Checked 9 Oct 2026. One AI model's read-back (currently Grok via API, not the consumer Grok app). One model, not a consensus.

Tested product: Mushroom Chocolate. Product page · Store

Score

of 100 · 0 of 5 shoppers added to cart

Browser shoppers

0 of 5

Browser cart shoppers that added the product to the cart. The score is this lane. The catalog check does not change it.

Tested 6 Oct 2026. How ARC tests

CAN AGENTS BUY

Agents can reach checkout through Shopify's agent catalog. Browser cart shoppers get stuck at adding the product to the cart.

AGENT CATALOG · REAL

Checkout link. The catalog returned the tested product.

ARC BROWSER CART TESTS

0 of 5 added the product to the cart. Stuck at adding the product to the cart.

View or refresh the free agent checkout check for us.foursigmatic.com →

GROK · REAL MODEL

One AI model's read-back recommended this.

Checked 9 Oct 2026. One AI model's read-back (currently Grok via API, not the consumer Grok app). One model, not a consensus.

Model x-ai/grok-4.20

Four Sigmatic Mushroom Chocolate provides tasty organic cacao with reishi for calm benefits versus plain cocoa. Consider alternatives for potentially lower prices or varied mushroom blends.

Rivals one model named: Om Mushroom, Host Defense, Real Mushrooms

MOST COSTLY MISMATCH

One AI model's read-back says your returns window is 60 days. Your site says 45 days.

Fact	Check	The model said	Store page
Returns window	Mismatch	60 days	45 daysPolicy pageItems returned to us after 45 days of the initial purchase date and/or without contacting Four Sigma FooSource page
Price	Couldn't verify	$28 for 30 servings subscribed	$70, $130, $190schema.org JSON-LD"sku": "816897021444-EA"Source page
Shipping cost	Grok didn't know	—	—
Availability	Match	in stock	in stockProduct page", "sku": "816897021444-EA", "gtin12": "816897021444", "availability" : "http://schema.org/InStock", "price" : 70.0, "priceCurrency" : "USD", "url" : "https:\/\/us.foursigmatic.cSource page
Delivery estimate	Couldn't verify	ships in 24 hours	—

Sources Grok cited

Each shopper

The failure

Couldn't add it to the cart

“Add to Cart” was clicked twice and the cart did not change. HTTP 200. Screenshot: /api/shot?p=runs%2FkWxBGHCdGQ5ekK_hD6otX%2Fmuse-step1-Ifne0lOD2P7EWfiwKDy8wJC4aJXCE9.png. This stopped 3 of 5 agents.

Top fix

Use a real Add to cart button, and show that the item landed in the cart.

History

6 Oct 202635/100 · browser 0 of 5 · Couldn't add it to the cart

Your store hub →

Is this your store?

The free scan puts the score on screen and emails the full report.

Get the free report →

Share this result

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OpenClaw only follows labelled controls. A block at the door is one result for all five, with the HTTP evidence. The score is the ARC browser cart, the same number as a free scan. The agent-catalog check above is real and leads the buy verdict. It does not change the score. How it works.

BADGE FOR YOUR SITE

Put this on your site. It links back here. It says Agent checkout when the real catalog check returned a checkout link, and Agents chose us only when a browser cart shopper added the product to the cart.

Four Sigmatic on the ARC Index. Agent checkout. ARC score 35. Agents can reach checkout through Shopify's agent catalog. Browser cart shoppers get stuck at adding the product to the cart.

<a href="https://www.arcreport.ai/agent-index/four-sigmatic"><img src="https://www.arcreport.ai/agent-index/four-sigmatic/badge" width="360" height="72" alt="Four Sigmatic on the ARC Index. Agent checkout. ARC score 35. Agents can reach checkout through Shopify's agent catalog. Browser cart shoppers get stuck at adding the product to the cart."></a>

Want a re-test, or this page removed? Contact ARC or email hello@arcreport.ai.