# add_attendee

Adds one or more attendees to an existing event.

Agent View of the PolicyLayer registry record for `add_attendee`. HTML page: https://policylayer.com/tools/deciduus-calendar-mcp/add-attendee

## Facts

- Tool: `add_attendee`
- Server: Calendar (`deciduus/calendar-mcp`) — https://policylayer.com/tools/deciduus-calendar-mcp.md
- Homepage: https://github.com/deciduus/calendar-mcp
- Risk category: Write (Medium risk)
- Registry record: grade D, identity unverified
- Server rate-limited: no
- Parameters: 0
- Recommended policy verdict: Rate-limited

## Example call (MCP tools/call, JSON-RPC 2.0)

```json
{
  "jsonrpc": "2.0",
  "id": 1,
  "method": "tools/call",
  "params": {
    "name": "add_attendee",
    "arguments": {}
  }
}
```

## 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 own 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)."

## Use case

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.

## Recommended policy (PolicyLayer)

Verdict: **Rate-limited**. Enforced by the PolicyLayer MCP gateway (https://policylayer.com/mcp-gateway) before a call reaches Calendar:

```json
{
  "version": "1",
  "default": "deny",
  "tools": {
    "add_attendee": {
      "limits": [
        {
          "counter": "add_attendee_rate",
          "window": "minute",
          "max": 30,
          "scope": "grant"
        }
      ]
    }
  }
}
```

## Other tools on Calendar (11)

- `delete_event` — Destructive — https://policylayer.com/tools/deciduus-calendar-mcp/delete-event.md
- `analyze_busyness` — Read — https://policylayer.com/tools/deciduus-calendar-mcp/analyze-busyness.md
- `check_attendee_status` — Read — https://policylayer.com/tools/deciduus-calendar-mcp/check-attendee-status.md
- `find_events` — Read — https://policylayer.com/tools/deciduus-calendar-mcp/find-events.md
- `list_calendars` — Read — https://policylayer.com/tools/deciduus-calendar-mcp/list-calendars.md
- `query_free_busy` — Read — https://policylayer.com/tools/deciduus-calendar-mcp/query-free-busy.md
- `create_calendar` — Write — https://policylayer.com/tools/deciduus-calendar-mcp/create-calendar.md
- `create_event` — Write — https://policylayer.com/tools/deciduus-calendar-mcp/create-event.md
- `quick_add_event` — Write — https://policylayer.com/tools/deciduus-calendar-mcp/quick-add-event.md
- `schedule_mutual` — Write — https://policylayer.com/tools/deciduus-calendar-mcp/schedule-mutual.md
- `update_event` — Write — https://policylayer.com/tools/deciduus-calendar-mcp/update-event.md

## For agents

This record is a snapshot. Live verdicts and the full registry:

- Check every server in your MCP config at once: `npx -y policylayer stack`
- Vet a server before you add it: install the mcp-precheck skill — `npx skills add https://policylayer.com` (skill text: https://policylayer.com/skill.md)
- Query the registry over MCP: endpoint `https://api.policylayer.com/mcp` — tools `check_mcp_server`, `check_mcp_stack`, `check_tool`, `search_registry`, `get_change_events`

---

Source: the PolicyLayer MCP registry — one continuously verified record per MCP server. Full record: https://policylayer.com/registry?q=deciduus-calendar-mcp · API: https://policylayer.com/registry/api · Policy library: https://policylayer.com/policies/deciduus-calendar-mcp