calendar__create_event

THE RISK

Medium Risk

Why calendar__create_event needs a policy

This tool creates new calendar events, which is a Write operation (data modification). The severity is medium because: (1) calendar events are typically user-controlled and reversible (can be deleted), (2) misuse could spam the user's calendar or create misleading reminders/deadlines, but (3) it does not delete data, execute code, or affect financial/security-critical systems.

From the tool's definition Tool name 'calendar__create_event' and description 'Create a calendar event' indicate data creation. The description specifies use cases: 'reminders, follow-ups, and deadlines'—all reversible calendar entries.

Documented attack patterns abuse exactly the kind of access calendar__create_event gives an agent:

POLICY

How to control calendar__create_event

PolicyLayer is an MCP gateway — it sits between your AI agents and Proton-MCP, and nothing reaches the server without passing your rules. This is the rule we recommend for calendar__create_event:

policy.json

{
  "version": "1",
  "default": "deny",
  "tools": {
    "calendar__create_event": {
      "limits": [
        {
          "counter": "calendar__create_event_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

calendar__create_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.

Create a free account and register Proton-MCP — nothing to install.
Add this policy — paste it, or build it visually.
Point your MCP client (Claude, Cursor, anything) at your gateway URL.

LIMIT THIS TOOL →

Free to start. No card required.

EXPLORE

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Write tools on other servers

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Go deeper

The MCP Attack Database → Documented attack patterns against MCP deployments — and the policies that stop them.
Argument validation → Checking tool call arguments against schema and policy before they run.
Scoped token → Per-person credentials that grant a defined subset of servers and tools.
Rate Limiting MCP Tool Calls: A Practical Guide →
MCP Security: Why Prompt Guardrails Aren't Enough →

FAQ

Questions about calendar__create_event

What does the calendar__create_event tool do? +

Create a calendar event. Use for reminders, follow-ups, and deadlines. It is categorised as a Write tool in the Proton-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__create_event? +

Register the Proton- MCP server in PolicyLayer and add a rule for calendar__create_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 Proton-MCP. Nothing to install.

What risk level is calendar__create_event? +

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

Can I rate-limit calendar__create_event? +

Yes. Add a rate_limit block to the calendar__create_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 calendar__create_event completely? +

Set action: deny in the PolicyLayer policy for calendar__create_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 calendar__create_event? +

calendar__create_event is provided by the Proton- MCP server (jorgenclaw/proton-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.

Enforce policy on every Proton-MCP tool call.

Start from Proton-MCP, add the rest of your stack, and see everything your agents can call. Then put policy on all of it.

CHECK YOUR STACK →