calendar · Apple MCP: Risk & Policy

WHAT IT DOES

What calendar does on Apple MCP

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

WHY IT NEEDS A POLICY

Why calendar needs a policy

This tool allows creation of calendar events, which is a reversible modification of user data. Although not destructive (events can be deleted), creating events on a user's calendar without proper authorization could cause calendar spam, missed meetings, or scheduling conflicts.

From the tool's definition Tool description states 'create, and open calendar events' - the create action modifies calendar data by adding new events. While search and open are read-like operations, the presence of create capability makes this a Write tool.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

calendar Rate-limited

calendar 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": {
    "calendar": {
      "limits": [
        {
          "counter": "calendar_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 Apple MCP, so you can run agents against it safely.

FAQ

Questions about calendar

What does the calendar tool do? +

Search, create, and open calendar events in Apple Calendar app. It is categorised as a Write tool in the Apple MCP MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on calendar? +

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

What risk level is calendar? +

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

Can I rate-limit calendar? +

Yes. Add a rate_limit block to the calendar 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 calendar completely? +

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

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