Slack Canvas Onboarding Checklist Automation Prompt

You are a DevEx engineer who automates onboarding and knows the Slack canvases
API (canvases.create, canvases.edit, canvases.sections.lookup,
canvases.access.set) and how canvases attach to channels or DMs.

I will provide:
- The onboarding checklist template (sections, tasks, owners, due offsets)
- Role variants (backend, SRE, data) that change some tasks
- Systems to integrate (HRIS start date, IdP access requests, calendar)
- Where the canvas should live (hire's onboarding channel or DM)

Your job:

1. **Template model** — a declarative onboarding spec (YAML) of sections and
   tasks with `owner`, `due_offset_days`, `role_tags`, and `link`; show how to
   render it into canvas markdown with checklist items.

2. **Provisioning flow** — on a new-hire trigger (HRIS webhook / slash command),
   create the canvas, write the role-filtered sections, and set access so the
   hire, manager, and buddy can edit; attach it to the onboarding channel.

3. **Progress tracking** — read checklist completion via
   canvases.sections.lookup, roll up percent-complete, and post a status
   summary; detect stalled tasks past their due offset.

4. **Reminders & nudges** — schedule reminders to task owners for overdue items
   using chat.scheduleMessage or reminders, with escalation to the manager if a
   blocking task (access, laptop) slips.

5. **Lifecycle** — archive/close the canvas at day-30 or 100% completion, and
   emit an onboarding-metrics record (time-to-first-PR, tasks completed on time).

6. **Idempotency & edge cases** — re-runs must not duplicate the canvas or
   tasks; handle a canceled hire, a role change mid-onboarding, and a missing
   Slack account gracefully.

Output: (a) YAML template schema with role variants, (b) create+edit+access
provisioning snippet, (c) completion-rollup logic, (d) reminder/escalation
design, (e) lifecycle + metrics, (f) an anti-pattern list (secrets in canvas,
duplicate provisioning, no owner on tasks).

Keep the checklist skimmable and every task owned, dated, and actionable.