add_url_attachment · MCP Apple Reminders MCP: Risk & Policy

WHAT IT DOES

What add_url_attachment does on MCP Apple Reminders

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

WHY IT NEEDS A POLICY

Why add_url_attachment needs a policy

This tool creates or modifies reminder data by attaching a URL, which is a reversible write operation. It does not execute code, delete data irreversibly, or move money. The empty description lowers confidence slightly, but the tool name and context clearly indicate a write/modification action rather than read-only or destructive behavior.

From the tool's definition Tool name 'add_url_attachment' suggests adding/attaching a URL to a reminder. The server description confirms it enables 'create, read, update, delete' operations on reminders.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_url_attachment Rate-limited

add_url_attachment 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_url_attachment": {
      "limits": [
        {
          "counter": "add_url_attachment_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 MCP Apple Reminders, so you can run agents against it safely.

FAQ

Questions about add_url_attachment

What does the add_url_attachment tool do? +

add_url_attachment. It is categorised as a Write tool in the MCP Apple Reminders 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_url_attachment? +

Register the MCP Apple Reminders MCP server in PolicyLayer and add a rule for add_url_attachment: 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 MCP Apple Reminders. Nothing to install.

What risk level is add_url_attachment? +

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

Can I rate-limit add_url_attachment? +

Yes. Add a rate_limit block to the add_url_attachment 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_url_attachment completely? +

Set action: deny in the PolicyLayer policy for add_url_attachment. 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_url_attachment? +

add_url_attachment is provided by the MCP Apple Reminders MCP server (rex/mcp-apple-reminders). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.