WebMCP Tools

Reference for the six WebMCP calendar tools FullCalendar WebMCP registers, including inputs, returns, and browser registration lifecycle.

FullCalendar WebMCP registers six tools on the browser’s WebMCP model context (document.modelContext).

For authentication boundaries, authorization, capability exposure, trust annotations, and data minimization, see Security.

For agent workflow patterns, relative-date handling, and tool-selection guidance, see Agent tool workflows.

Tools

calendar_get_context

Returns current time, timezones, and the active viewport. Agents should call this before resolving relative dates (“tomorrow at 2pm”).

Input: {}

Returns:

{
  "now": "2026-09-01T14:30:00.000Z",
  "browserTimeZone": "America/Denver",
  "fullCalendarTimeZone": "local",
  "view": "dayGridMonth",
  "visibleRange": {
    "start": "2026-08-30T06:00:00.000Z",
    "end": "2026-10-04T06:00:00.000Z"
  }
}

calendar_list_events

Lists persisted events, optionally filtered by range or title.

Input: optional start, end, text

Returns: { "events": CalendarEvent[] } (may include host metadata)

calendar_get_event

Fetches one event by id.

Input: id (required)

Returns: { "event": CalendarEvent | null }

calendar_create_event

Creates and persists an event.

Input: title, start (ISO 8601 with offset), optional end, optional allDay

Returns: { "event": CalendarEvent }

Write schemas reject metadata.

calendar_update_event

Updates fields on an existing event. At least one of title, start, end, allDay is required.

Returns: { "event": CalendarEvent }

Write schemas reject metadata. Host-owned metadata is preserved by your repository across core-field updates.

calendar_delete_event

Permanently deletes an event by id.

Returns: { "deleted": true, "event": CalendarEvent } — event is a snapshot read immediately before removal (title, times, optional metadata preserved for agent confirmation).

Lifecycle

On mount, useFullCalendarWebMCP registers the tools (and polls briefly if the WebMCP runtime appears late). On unmount, it unregisters them. React Strict Mode double-mount is handled cleanly.

Optional capabilities limit which tools register — see Security.

Verify with the Testing checklist.