calendar_forward_event · M365 MCP: Risk & Policy

WHAT IT DOES

What calendar_forward_event does on M365

AI agents use calendar_forward_event to create or update resources in M365 — usually the action step of a workflow, after the agent has gathered context. Every call changes real data in your M365 environment.

WHY IT NEEDS A POLICY

Why calendar_forward_event needs a policy

Forwarding a calendar event constitutes a reversible write operation—it shares or modifies event distribution without deleting data or executing arbitrary code. While not destructive, it does create side effects (notifications, shared event state).

From the tool's definition Tool name 'calendar_forward_event' indicates modification of calendar events (forwarding/sharing); part of Microsoft 365 Calendar API suite for managing calendar data; description is empty but context suggests calendar event manipulation.

Attacks that exploit this kind of access

Recommended rule Ready

Verdict

calendar_forward_event Rate-limited

calendar_forward_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": {
    "calendar_forward_event": {
      "limits": [
        {
          "counter": "calendar_forward_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 M365, so you can run agents against it safely.

FAQ

Questions about calendar_forward_event

What does the calendar_forward_event tool do? +

calendar_forward_event. It is categorised as a Write tool in the M365 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_forward_event? +

Register the M365 MCP server in PolicyLayer and add a rule for calendar_forward_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 M365. Nothing to install.

What risk level is calendar_forward_event? +

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

Can I rate-limit calendar_forward_event? +

Yes. Add a rate_limit block to the calendar_forward_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_forward_event completely? +

Set action: deny in the PolicyLayer policy for calendar_forward_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_forward_event? +

calendar_forward_event is provided by the M365 MCP server (robin-collins/m365-mcp). PolicyLayer sits as a proxy in front of this server to enforce policies before tool calls reach the server.