add_subscriber

Add subscriber to ConvertKit

SERVERNcp SOURCE@portel/ncp

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/io-github-portel-dev-ncp/add-subscriber.md

WHAT IT DOES

What add_subscriber does on Ncp

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

RISK

Why add_subscriber is rated Medium

This tool creates a new subscriber record, which is a reversible write operation. It modifies data (adds an entry) but doesn't delete or overwrite existing data irreversibly, nor does it execute arbitrary code or move money.

From the tool's definition Tool name 'add_subscriber' and description 'Add subscriber to ConvertKit' indicate creation of a new record in an external service (ConvertKit email/marketing platform).

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs add_subscriber safely

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

add_subscriber Rate-limited

add_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": {
    "add_subscriber": {
      "limits": [
        {
          "counter": "add_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 Ncp, apply this rule, and every add_subscriber call is checked against it from then on.

FAQ

Questions about add_subscriber

What does the add_subscriber tool do? +

Add subscriber to ConvertKit. It is categorised as a Write tool in the Ncp MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_subscriber? +

Register the Ncp MCP server in PolicyLayer and add a rule for add_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 Ncp. Nothing to install.

What risk level is add_subscriber? +

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

Can I rate-limit add_subscriber? +

Yes. Add a rate_limit block to the add_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 add_subscriber completely? +

Set action: deny in the PolicyLayer policy for add_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 add_subscriber? +

add_subscriber is provided by the Ncp MCP server (@portel/ncp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

KEEP EXPLORING

More on Ncp, and thousands of servers like it.

This server

All 275 Ncp tools →

Across the catalogue

add-tag on Kanban MCP Server →kb_add on Persistent Kb →add_video on Mcptube Vision → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →