{
  "subject": "Incident started: ${incident_id}",
  "body": "Incident ${incident_id} started at ${started_at}. Severity: ${severity}.",
  "merge_fields": ["incident_id", "started_at", "severity"],
  "preview_hash": "05eb80e384eaf6edf0c44a655ca9064ca4e88b8ad7cefa1483eda5c9aaface00"
}