ical__update_event · Mcp Ical Swift MCP: Risk & Policy

WHAT IT DOES

What ical__update_event does on Mcp Ical Swift

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

WHY IT NEEDS A POLICY

Why ical__update_event needs a policy

This tool modifies existing calendar events reversibly—the update can be undone by changing the fields back. It does not delete data (which would be Destructive) nor does it create new events (that would be a separate Write operation).

From the tool's definition Tool description states 'Update fields on a single existing calendar event' and 'only fields you provide are changed', which is clearly a modification operation. The tool operates on calendar data via Apple's EventKit framework.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

ical__update_event Rate-limited

ical__update_event 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": {
    "ical__update_event": {
      "limits": [
        {
          "counter": "ical__update_event_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 Ical Swift, so you can run agents against it safely.

FAQ

Questions about ical__update_event

What does the ical__update_event tool do? +

Update fields on a single existing calendar event; only fields you provide are changed. For recurring events this modifies the single occurrence only (EventKit. It is categorised as a Write tool in the Mcp Ical Swift MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on ical__update_event? +

Register the Mcp Ical Swift MCP server in PolicyLayer and add a rule for ical__update_event: 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 Ical Swift. Nothing to install.

What risk level is ical__update_event? +

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

Can I rate-limit ical__update_event? +

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

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

ical__update_event is provided by the Mcp Ical Swift MCP server (sealjay/mcp-ical-swift). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.