[Solved] Storefront MCP search_shop_catalog returns GraphQL schema errors - product discovery is currently broken

MCP & LLM
1

Hi Shopify team and community,

I’ve discovered a critical bug in the Storefront MCP that makes the search_shop_catalog tool completely unusable. This affects all Shopify stores and breaks the primary advertised feature of Storefront MCP: product discovery.

When calling search_shop_catalog via the /api/mcp endpoint, the tool always fails with GraphQL schema errors, regardless of the parameters used:

{
  "content": [
    {
      "type": "text",
      "text": "[\"Field 'optionValues' doesn't exist on type 'ProductOption'\",\"Field 'category' doesn't exist on type 'Product'\",\"Field 'encodedVariantAvailability' doesn't exist on type 'Product'\",\"Field 'variantsCount' doesn't exist on type 'Product'\"]"
    }
  ],
  "isError": true
}

The MCP server appears to be querying fields from the unrelated API instead of the Storefront API? Every single attempt returns the same GraphQL schema errors.

Other tools like search_shop_policies_and_faqs and get_product_details works perfectly. MCP endpoint itself is functional, but search_shop_catalog is broken.

I’ve seen other search_shop_catalog issues in the community (null filters, price filter ignored, metafield filters not working), but none report GraphQL schema errors. This appears to be a distinct, unreported bug.

Could the Shopify team please investigate this GraphQL schema mismatch?

Has anyone else encountered this issue? Any workarounds while we wait for a fix?

Thanks!

2

This feature was working flawlessly yesterday but suddenly getting this error now on search_shop_catalog tool call.

I am getting this error:

["Field 'optionValues' doesn't exist on type 'ProductOption'","Field 'category' doesn't exist on type 'Product'","Field 'encodedVariantAvailability' doesn't exist on type 'Product'","Field 'variantsCount' doesn't exist on type 'Product'"]
3

Did we find any solution for this? Looks like something broke today.

4

Any updates here. I am facing the same Problem.

5

Seems like it is working again!

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