You are helping me build the following AI agent workflow.

## Goal
Shopify Order Fulfillment & WhatsApp Tracking: On new Shopify fulfillment, validates customer phone via Rapiwa API and sends a WhatsApp tracking message if verified.

## Specification
- What it does: Get instant WhatsApp tracking updates for your customers whenever a new order is fulfilled on Shopify. The system automatically validates phone numbers through the Rapiwa API to ensure message delivery, then sends personalized tracking details while logging every interaction in Google Sheets for easy auditing.
- Trigger: Triggered by an event (Event · on new Shopify fulfillment)
- Autonomy: Fully hands-off
- Expected setup effort: about an afternoon
- Tools/services involved:
  - n8n: Workflow orchestration platform
  - Shopify: Order and customer data source
  - Rapiwa API: WhatsApp number validation and messaging
  - Google Sheets: Logging verified and unverified interactions

## Known pitfalls, handle each one explicitly in your implementation
1. Invalid phone numbers will cause message delivery failures, so add a conditional branch to skip unverified contacts gracefully.
2. Sensitive customer data is exposed in logs if not masked properly, so ensure phone numbers are anonymized in the final sheet output.

## Reference implementation
https://n8n.io/workflows/9003 (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/shopify-order-fulfillment-whatsapp-tracking/ via usecasesforagents.com