add_attendee

Adds one or more attendees to an existing event.

SERVERCalendar SOURCEdeciduus/calendar-mcp

Medium RISK CLASS

Category Write

Parameters 00 required

Recommended Rate-limitedsee the rule below

Registry record Grade D, identity unverified Pull the record →

This record as markdown: /tools/deciduus-calendar-mcp/add-attendee.md

WHAT IT DOES

What add_attendee does on Calendar

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

RISK

Why add_attendee is rated Medium

Adding attendees to a calendar event modifies existing data but the change is reversible (attendees can be removed later). This fits the Write category rather than Execute or Destructive. Severity is medium because misuse could disrupt calendar coordination by inviting unintended parties to events, but the impact is limited to calendar state and does not cause irreversible data loss or financial harm.

From the tool's definition Tool name 'add_attendee' and description 'Adds one or more attendees to an existing event' indicate modification of event data. This is a reversible change (attendees can be removed).

Attacks that exploit this kind of access

RECOMMENDED RULE

The rule that runs add_attendee safely

PolicyLayer is an MCP gateway: it sits between your AI agents and Calendar, and checks every tool call against a rule you set before the call runs. Nothing changes on the server itself. For add_attendee, this is the rule to start with:

add_attendee Rate-limited

add_attendee 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": {
    "add_attendee": {
      "limits": [
        {
          "counter": "add_attendee_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}

LIMIT THIS TOOL → Instant setup, no code required.

The button opens the PolicyLayer dashboard: create your workspace, connect Calendar, apply this rule, and every add_attendee call is checked against it from then on.

FAQ

Questions about add_attendee

What does the add_attendee tool do? +

Adds one or more attendees to an existing event. It is categorised as a Write tool in the Calendar MCP Server, which means it can create or modify data. Consider rate limits to prevent runaway writes.

How do I enforce a policy on add_attendee? +

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

What risk level is add_attendee? +

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

Can I rate-limit add_attendee? +

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

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

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

KEEP EXPLORING

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This server

All 12 Calendar tools →

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add-tag on Kanban MCP Server →kb_add on Persistent Kb → The MCP Attack Database →

Guides

Govern customer-ops agents →Argument validation →Scoped token →