create_webhook_subscription · Shopify Graphql MCP

WHAT IT DOES

What create_webhook_subscription does on Shopify Graphql

AI agents use create_webhook_subscription to create or update resources in Shopify Graphql — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your Shopify Graphql environment.

WHY IT NEEDS A POLICY

Why create_webhook_subscription needs a policy

This tool creates new webhook subscriptions, which modifies Shopify's event notification system reversibly. While webhook misconfiguration could enable data exfiltration or trigger unintended external actions via the specified endpoints (HTTPS, Pub/Sub, EventBridge), the tool itself performs a Write operation—creating configuration objects.

From the tool's definition Tool name contains 'create' and description states 'Create a webhook subscription', indicating data creation. The tool configures event subscriptions that modify Shopify's webhook routing configuration.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_webhook_subscription Rate-limited

create_webhook_subscription stays usable, but capped — an agent stuck in a loop can't make hundreds of changes a minute. Everything else on the server is denied unless you say otherwise.

View as policy code

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "create_webhook_subscription": {
      "limits": [
        {
          "counter": "create_webhook_subscription_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL →

Instant setup, no code required.

PolicyLayer is an MCP gateway: every tool call is checked against your rule before it reaches Shopify Graphql, so you can run agents against it safely.

FAQ

Questions about create_webhook_subscription

What does the create_webhook_subscription tool do? +

Create a webhook subscription. Supports HTTPS URLs, Google Pub/Sub topics (pubsub://project:topic), and AWS EventBridge (arn:aws:events:...). It is categorised as a Write tool in the Shopify Graphql MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_webhook_subscription? +

Register the Shopify Graphql MCP server in PolicyLayer and add a rule for create_webhook_subscription: allow, deny, rate-limit, or require approval. Point your MCP client at the PolicyLayer proxy URL and the rule is enforced on every call, before it reaches Shopify Graphql. Nothing to install.

What risk level is create_webhook_subscription? +

create_webhook_subscription is a Write tool with medium risk. Write tools should be rate-limited to prevent accidental bulk modifications.

Can I rate-limit create_webhook_subscription? +

Yes. Add a rate_limit block to the create_webhook_subscription rule in your PolicyLayer policy. For example, setting max: 10 and window: 60 limits the tool to 10 calls per minute. Rate limits are tracked per agent session and reset automatically.

How do I block create_webhook_subscription completely? +

Set action: deny in the PolicyLayer policy for create_webhook_subscription. The AI agent will receive a policy violation error and cannot call the tool. You can also include a reason field to explain why the tool is blocked.

What MCP server provides create_webhook_subscription? +

create_webhook_subscription is provided by the Shopify Graphql MCP server (uvu-store/shopify-graphql-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.