Escalate urgent support tickets to Slack in real time

A support team describes their process like this: "When a customer submits a support
ticket tagged 'urgent' or mentions 'refund' or 'cancel' in the message, I want it
posted immediately to our #escalations Slack channel and assigned to whoever is
on-call, so nothing urgent sits in the queue overnight."

AVAILABLE TOOLS: [Help desk ticketing system (trigger), Uncanny Automator, Slack,
on-call schedule tool]

Turn this into an implementation-ready automation recipe, thinking through what the
plain description leaves ambiguous:
1. Trigger: the exact combination of tag-based and keyword-based matching, and how to
   avoid false positives, since a ticket that says "please cancel my duplicate order,
   everything else is fine" would trip the keyword match but isn't actually urgent.
2. Conditions: state the exact logic for pulling "whoever is on-call" from the
   schedule tool, including what happens at the exact boundary when a shift changes
   mid-ticket, so the ticket doesn't get assigned to someone who just went off duty.
3. Actions in order: post to Slack with the ticket summary and a direct link, then
   assign the ticket in the help desk tool, then tag the on-call person by their
   actual Slack handle, not just their name, so the notification pings them.
4. Failure handling: if the on-call schedule tool is unreachable and the current
   on-call person can't be determined, should the ticket still post to Slack
   unassigned with an @here, or fall back to a fixed backup contact.
5. One edge case specific to this exact workflow: the same customer submitting three
   "urgent" tickets in ten minutes about the same issue. Decide whether each one
   re-escalates and re-pings, or whether the recipe should detect the duplicate and
   thread it under the first escalation instead.

Replace the workflow description and available tools with your own.