> ## Documentation Index
> Fetch the complete documentation index at: https://docs.langmail.me/llms.txt
> Use this file to discover all available pages before exploring further.

# respond_to_event

> RSVP to a calendar invitation — accept, decline, or tentative — on the authenticated user's behalf.

Sets the user's own attendance status on an event they were invited to and saves it back; the organizer is notified automatically. This only answers the invitation — it never modifies the event itself.

## Parameters

<ParamField body="uid" type="string" required>
  The event's iCalendar UID, from [`list_calendar_events`](/reference/mcp/list-calendar-events).
</ParamField>

<ParamField body="response" type="string" required>
  One of `accept`, `decline`, or `tentative`.
</ParamField>

<ParamField body="calendarUrl" type="string">
  A CalDAV URL from [`list_calendars`](/reference/mcp/list-calendars). Defaults to the user's default calendar — pass this if the invitation lives in another calendar.
</ParamField>

## Example

```json Call theme={null}
{ "uid": "5f2e8c1d-4b3a-4f6e-9d2c-1a0b9c8d7e6f@example.com", "response": "accept" }
```

```text Result theme={null}
RSVP'd accepted to "Planning".
```

## Errors

* `You are not an attendee of this event, so you can't RSVP.` — the event doesn't list the user as an attendee.
* `Event not found: <uid>` — no event with that UID in the target calendar.
* `Calendar not found: <url>` — the `calendarUrl` didn't resolve.