curl --request GET \
  --url https://your-instance.example.com/api/organizations/{organizationId}/missed-call-message/placeholders \
  --header 'Authorization: Bearer <token>'

{
  "placeholders": [
    {
      "token": "{{contactName}}",
      "label": "Contact full name"
    },
    {
      "token": "{{agentName}}",
      "label": "Assigned agent name"
    },
    {
      "token": "{{organizationName}}",
      "label": "Organization display name"
    }
  ]
}