How to include metafields in webhook payloads for `product_feeds/incremental_sync` or product_feeds/full_sync`

Webhooks and Events
1

Hi there! I am trying to achieve the following:

Goal

Add metafields to the PRODUCT_FEEDS_FULL_SYNC and PRODUCT_FEEDS_INCREMENTAL_SYNC webhook payloads.

What I tried

  1. Added metafieldNamespaces to the EventBridge webhook subscription when creating webhooks for product feed topics.
await client.request(EventBridgeWebhookSubscriptionCreateMutation, {
  variables: {
    topic: "PRODUCT_FEEDS_FULL_SYNC", // also INCREMENTAL_SYNC and FULL_SYNC_FINISH
    webhookSubscription: {
      arn: "arn:aws:events:us-east-1::.<arn>",
      metafieldNamespaces: ["custom"]
    }
  }
});
  1. Verified the webhook subscriptions were created correctly by querying them:

The response confirmed metafieldNamespaces: \["custom"\] was set on all three product feed webhook subscriptions.

  1. Triggered a full sync using productFullSync mutation.

Result

The webhook payloads were received but did NOT contain any metafields - only the standard product/variant fields.

So my questions are:

  1. Does metafieldNamespaces work with PRODUCT_FEEDS_FULL_SYNC and PRODUCT_FEEDS_INCREMENTAL_SYNC webhook topics?

  2. Is there a different way to include metafields in product feed sync payloads?

  3. Are there any limitations or requirements for metafields to appear in product feed webhooks (e.g., metafield definitions required, specific access scopes)?

Thanks in advance for your help!