add_metadata · MCP Apple Reminders MCP: Risk & Policy

WHAT IT DOES

What add_metadata does on MCP Apple Reminders

AI agents use add_metadata 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_metadata needs a policy

This tool most likely creates or modifies reminder metadata reversibly (Write category), which is less severe than destructive operations. The medium severity reflects that metadata modification could affect reminder organization or functionality, but reminders are typically non-critical personal data. The 65% confidence accounts for the empty description, requiring inference from the tool name and server context.

From the tool's definition The tool name 'add_metadata' combined with the server's purpose of managing reminders suggests this tool creates or modifies metadata associated with reminders or lists.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

add_metadata Rate-limited

add_metadata 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_metadata": {
      "limits": [
        {
          "counter": "add_metadata_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_metadata

What does the add_metadata tool do? +

add_metadata. 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_metadata? +

Register the MCP Apple Reminders MCP server in PolicyLayer and add a rule for add_metadata: 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_metadata? +

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

Can I rate-limit add_metadata? +

Yes. Add a rate_limit block to the add_metadata 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_metadata completely? +

Set action: deny in the PolicyLayer policy for add_metadata. 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_metadata? +

add_metadata 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.