create_calendar · Mcp Ical MCP: Risk & Policy

WHAT IT DOES

What create_calendar does on Mcp Ical

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

WHY IT NEEDS A POLICY

Why create_calendar needs a policy

Creating calendar files is a Write operation because it generates and structures data that can be modified or deleted later. Severity is medium because misuse could create spam calendar events or inject malicious calendar data into systems, but the impact is limited to calendar data rather than system-wide or financial consequences.

From the tool's definition Tool description states 'Build a multi-event ICS calendar file' — this creates new calendar data structures. The verb 'build' indicates data generation/creation, which is a Write operation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

create_calendar Rate-limited

create_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": {
    "create_calendar": {
      "limits": [
        {
          "counter": "create_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 Mcp Ical, so you can run agents against it safely.

FAQ

Questions about create_calendar

What does the create_calendar tool do? +

Build a multi-event ICS calendar file from an array of events. It is categorised as a Write tool in the Mcp Ical MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on create_calendar? +

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

What risk level is create_calendar? +

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

Can I rate-limit create_calendar? +

Yes. Add a rate_limit block to the create_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 create_calendar completely? +

Set action: deny in the PolicyLayer policy for create_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 create_calendar? +

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