You are helping me build the following AI agent workflow.

## Goal
Recover Abandoned Carts via Multi-Channel Retargeting: Monitors abandoned Shopify carts and runs a timed multi-channel recovery sequence via email, SMS, and WhatsApp with dynamic discounts.

## Specification
- What it does: You recover abandoned Shopify sales by automatically sending personalized emails, SMS, and WhatsApp messages with dynamic discounts to your customers based on their history. The agent logs every interaction for analysis and adds unrecovered carts to Facebook Custom Audiences so you can retarget them effectively.
- Trigger: Triggered by an event (Event · on abandoned cart webhook)
- Autonomy: Fully hands-off
- Expected setup effort: a few focused days
- Tools/services involved:
  - Shopify: Trigger and cart data retrieval
  - SendGrid: Sending personalized email follow-ups
  - Twilio: Sending SMS discount codes
  - WhatsApp Business Cloud: Sending final WhatsApp reminders
  - Google Sheets: Logging touchpoints for attribution analysis

## Known pitfalls, handle each one explicitly in your implementation
1. WhatsApp Business API requires pre-approved templates so you must submit variations in advance or use fallback logic.
2. Facebook Custom Audiences take up to 24 hours to update so retargeting ads will not fire immediately after adding users.

## Reference implementation
https://n8n.io/workflows/11805 (workflow template)
Fetch and inspect this before building. If it matches my stack, adapt it;
if not, rebuild the pattern with my tools.

## Process requirements
1. Before building: ask me which of the listed tools I actually use and
   what my platform is (n8n / Make / code / other). Do not assume.
2. Adapt the pattern to my answers; do not force the reference stack.
3. Address every pitfall above; tell me how you handled each.
4. Provide a test plan I can run before letting this touch real data.
5. Ask before any step that sends messages, modifies data, or spends money.

Source: https://usecasesforagents.com/use-case/recover-abandoned-carts-via-multi-channel-retargeting/ via usecasesforagents.com