shopify-admin-return-fraud-detector

What this skill does

## Purpose
Surfaces customers whose return behavior deviates statistically from the store baseline so support and ops can review them before approving the next return. Three patterns are detected: (1) high return rate (≥40% of orders returned), (2) wardrobing — full-order returns shortly after delivery, (3) serial returners — many returns over time. Read-only. Output is a candidate list, not an automatic block list.

## Prerequisites
- Authenticated Shopify CLI session: `shopify store auth --store <domain> --scopes read_orders,read_returns,read_customers`
- API scopes: `read_orders`, `read_returns`, `read_customers`

## Parameters

| Parameter | Type | Required | Default | Description |
|-----------|------|----------|---------|-------------|
| store | string | yes | — | Store domain (e.g., mystore.myshopify.com) |
| format | string | no | human | Output format: `human` or `json` |
| days_back | integer | no | 365 | Lookback window for orders and returns |
| min_orders | integer | no | 3 | Minimum lifetime orders for a customer to be evaluated (avoid penalizing one-off accidents) |
| return_rate_threshold | float | no | 0.40 | Fraction of orders returned to flag as high (default 40%) |
| wardrobing_window_days | integer | no | 14 | Window between delivery and return-initiated to flag as wardrobing |
| serial_threshold | integer | no | 5 | Minimum total returns to flag as serial returner |

## Safety

> ℹ️ Read-only skill — no mutations are executed. Output flags candidates for human review only — never block or restrict customers automatically. False positives are common (genuine size issues, address-correction returns, etc.); investigate before action.

## Workflow Steps

1. **OPERATION:** `orders` — query
   **Inputs:** `query: "created_at:>='<NOW - days_back days>'"`, `first: 250`, select `id`, `customer { id }`, `processedAt`, `fulfillments { deliveredAt }`, `totalPriceSet`, `lineItems { quantity }`, paginate
   **Expected output:** All orders in window grouped by `customer.id`

2. **OPERATION:** `returns` — query
   **Inputs:** Same date filter, `first: 250`, select `id`, `createdAt`, `order { customer { id } }`, `returnLineItems { quantity }`, `totalQuantity`
   **Expected output:** All returns in window joined to customer

3. **OPERATION:** `customers` — query
   **Inputs:** For flagged candidates only: `query: "id:<ids>"`, select identity fields and `tags`
   **Expected output:** Contact data for the candidates list

4. Per customer compute `total_orders`, `total_returns`, `return_rate`, `wardrobing_count` (returns within `wardrobing_window_days` of delivery where Σ return qty ≥ Σ order qty). Flag rules: `high_return_rate` (orders ≥ `min_orders` AND rate ≥ `return_rate_threshold`), `wardrobing` (count ≥ 2), `serial_returner` (returns ≥ `serial_threshold`).

## GraphQL Operations

```graphql
# orders:query — validated against api_version 2025-01
query OrdersForReturnFraud($query: String!, $after: String) {
  orders(first: 250, after: $after, query: $query) {
    edges {
      node {
        id
        name
        processedAt
        displayFulfillmentStatus
        totalPriceSet { shopMoney { amount currencyCode } }
        customer { id }
        lineItems(first: 50) {
          edges { node { id quantity } }
        }
        fulfillments {
          deliveredAt
          status
          displayStatus
        }
      }
    }
    pageInfo { hasNextPage endCursor }
  }
}
```

```graphql
# returns:query — validated against api_version 2025-01
query ReturnsForFraud($query: String!, $after: String) {
  returns(first: 250, after: $after, query: $query) {
    edges {
      node {
        id
        status
        createdAt
        totalQuantity
        order { id name customer { id } }
        returnLineItems(first: 50) {
          edges { node { id quantity returnReason } }
        }
      }
    }
    pageInfo { hasNextPage endCursor }
  }
}
```

```graphql
# customers:query — validated against api_version 2025-01
query CustomerContactBatch($query: String!) {
  customers(first: 250, query: $query) {
    edges {
      node {
        id
        displayName
        firstName
        lastName
        defaultEmailAddress { emailAddress }
        phone
        numberOfOrders
        amountSpent { amount currencyCode }
        tags
      }
    }
  }
}
```

## Session Tracking

**Claude MUST emit the following output at each stage. This is mandatory.**

**On start**, emit:
```
╔══════════════════════════════════════════════╗
║  SKILL: Return Fraud Detector                ║
║  Store: <store domain>                       ║
║  Started: <YYYY-MM-DD HH:MM UTC>             ║
╚══════════════════════════════════════════════╝
```

**After each step**, emit:
```
[N/TOTAL] <QUERY|MUTATION>  <OperationName>
          → Params: <brief summary of key inputs>
          → Result: <count or outcome>
```

**On completion**, emit:

For `format: human` (default):
```
══════════════════════════════════════════════
RETURN FRAUD CANDIDATES  (<days_back> days)
  Customers evaluated:      <n>
  Flagged candidates:       <n>

  By rule:
    High return rate (≥<pct>%):  <n>
    Wardrobing pattern:           <n>
    Serial returner (≥<n>):       <n>

  Top suspects (by composite risk):
    <name>  <email>  Orders: <n>  Returns: <n>  Rate: <pct>%  Flags: <list>
  Output: return_fraud_candidates_<date>.csv
══════════════════════════════════════════════
```

For `format: json`, emit:
```json
{
  "skill": "return-fraud-detector",
  "store": "<domain>",
  "period_days": 365,
  "customers_evaluated": 0,
  "flagged_candidates": 0,
  "by_rule": {
    "high_return_rate": 0,
    "wardrobing": 0,
    "serial_returner": 0
  },
  "output_file": "return_fraud_candidates_<date>.csv"
}
```

## Output Format
CSV file `return_fraud_candidates_<YYYY-MM-DD>.csv` with columns:
`customer_id`, `name`, `email`, `phone`, `total_orders`, `total_returns`, `return_rate_pct`, `wardrobing_count`, `flags`, `lifetime_spend`, `last_return_date`, `tags`

## Error Handling
| Error | Cause | Recovery |
|-------|-------|----------|
| `THROTTLED` | API rate limit exceeded | Wait 2 seconds, retry up to 3 times |
| Customer null on order | Guest checkout | Skip — cannot link multiple orders to a guest |
| Return missing `order.customer` | Anonymized or deleted | Skip return |
| `deliveredAt` missing | Order not yet delivered | Skip wardrobing flag for the order |

## Best Practices
- Treat output as a review queue, never an automatic action — manually validate before tagging or restricting any account.
- Tune `return_rate_threshold` to your category baseline. Apparel stores run 20–30% return rates; flagging at 40% picks outliers. For electronics or homewares, drop to 15–20%.
- Cross-reference with `return-reason-analysis` — if returns concentrate on one product, the issue may be product quality, not abuse.
- Pair with `customer-merge` candidates from `duplicate-customer-finder` — fraudsters often create duplicate accounts to dodge return-rate flags.
- Run quarterly with a 12-month window for stable signal; monthly runs produce noisy flags from new customers with one return.