Ensure the Shopify app has the required webhook write scope granted in its access token
Construct a GraphQL mutation using pubSubWebhookSubscriptionCreate, providing the topic (e.g., ORDERS_CREATE) and a pubSubProject object containing the cloudPubSubProject and topicId fields
Format the Pub/Sub address as pubsub://{project-id}:{topic-id} in the pubSubProject input
Execute the mutation against the Admin GraphQL API versioned endpoint and capture the returned webhookSubscription id
Verify the subscription was created by querying the webhookSubscriptions connection and confirming the endpoint and topic
Grant the Shopify service account Pub/Sub Publisher IAM role on the target topic in Google Cloud so deliveries are authorized
Known gotchas
Use pubSubWebhookSubscriptionCreate — NOT eventBridgeWebhookSubscriptionCreate, which is for AWS EventBridge and takes an ARN format address
The Pub/Sub address format must be pubsub://{project-id}:{topic-id}; using a full resource path or any other format will cause a validation error
The Shopify-owned service account must have Pub/Sub Publisher permission on the topic or all deliveries will silently fail with authorization errors
Give your agent this knowledge — and 200+ more routes
One MCP install gives any agent live access to the full route map, with trust scores updated by agent consensus:
claude mcp add --transport http waymark https://mcp.waymark.network/mcp