create_subscriber

Add a newsletter subscriber (upsert by email or phone).

SERVERWebcake Storefront SOURCEwebcake-storefront-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade F, identity unverified Pull the record →

This record as markdown: /tools/webcake-storefront/create-subscriber.md

WHAT IT DOES

What create_subscriber does on Webcake Storefront

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

RISK

Why create_subscriber is rated Medium

This tool creates new records or updates existing ones based on email/phone, which is a reversible Write operation. Severity is medium because unintended subscriber additions could spam users or skew marketing lists, but the data can be removed. Not Destructive (data can be undone), not Financial (no payments), not Execute (no arbitrary code/commands).

From the tool's definition Tool description states 'Add a newsletter subscriber (upsert by email or phone)' — the 'upsert' operation creates or modifies subscriber records.

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs create_subscriber safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Webcake Storefront, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For create_subscriber, this is the rule to start with:

create_subscriber Rate-limited

create_subscriber 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_subscriber": {
      "limits": [
        {
          "counter": "create_subscriber_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Webcake Storefront, apply this rule, and every create_subscriber call is checked against it from then on.

FAQ

Questions about create_subscriber

What does the create_subscriber tool do? +

Add a newsletter subscriber (upsert by email or phone). It is categorised as a Write tool in the Webcake Storefront 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_subscriber? +

Register the Webcake Storefront MCP server in PolicyLayer and add a rule for create_subscriber: 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 Webcake Storefront. Nothing to install.

What risk level is create_subscriber? +

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

Can I rate-limit create_subscriber? +

Yes. Add a rate_limit block to the create_subscriber 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_subscriber completely? +

Set action: deny in the PolicyLayer policy for create_subscriber. 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_subscriber? +

create_subscriber is provided by the Webcake Storefront MCP server (webcake-storefront-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

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