Support VALARM as a Calendar Trigger

[MYLE-01]

Describe your idea

Hi all,

I’d like to request support for triggering Home Assistant automations directly from ICS VALARM entries.

Right now, Home Assistant reads VALARM blocks inside ICS files, but they can’t be used as automation triggers. Instead, we have to recreate the alarm timing manually using event: start with an offset:.

Why this matters

ICS calendars (RFC 5545) support rich alarm definitions:

• Multiple alarms per event
• Different alarm types (DISPLAY, AUDIO, EMAIL, etc.)
• Per‑event alarm configuration
• Human‑readable alarm descriptions

Home Assistant already parses these alarms internally, so exposing them as triggers would make calendar automations much more powerful and reduce duplicated logic.

Example ICS

BEGIN:VEVENT 
DTSTART:20260526T170000 
SUMMARY:Night Shift 
BEGIN:VALARM 
TRIGGER:-PT120M 
ACTION:DISPLAY 
DESCRIPTION:Shift Alarm 
END:VALARM 
END:VEVENT

Why is this exciting?

Benefits

• ICS becomes the single source of truth
• No more manually calculating offsets
• Supports multiple alarms per event
• Cleaner automations
• Fully backwards‑compatible

This would be especially useful for shift workers, medication reminders, school schedules, and travel itineraries.

Thanks for considering it — happy to provide more examples if needed.

Potential use cases

Proposed YAML

trigger:
 - platform:  calendar
   event: valarm 
   entity_id: calendar.roster

Optional filters (if supported):

alarm_index: 0
alarm_type: display 
description: "Shift Alarm"

Anything else?

No response