# Dozenfold — example developer brief

Illustrative product-tour data. This is a fictional issue, not a customer incident.
Use it to see the kind of evidence you can take from Dozenfold into your team's workflow.

## Issue

DF-1876 — Cart update fails after a delivery change

- Error: TypeError: Cannot read properties of undefined
- Observed environment: production, Mobile Safari
- Release: storefront@2.18.4
- Affected surface: storefront cart delivery selector

## Observed journey

1. 12:41:58 — Viewed /products/ridge-jacket
2. 12:42:11 — Added a variant to the cart
3. 12:42:46 — Changed the cart delivery option
4. 12:42:47 — POST /cart/update failed; TypeError captured

These are captured events, not a screen recording or a guaranteed reproduction.
No shopper identity, typed value, request body or response body is included.

## Original source context

Available in this example because a usable source map was uploaded.

```ts
// cart.ts:184 — illustrative source
const rate = rates.find(matchRate);
setPending(true);
rate.handle; // captured failing line
await updateCart(rate);
```

## Investigation starting point

Inspect how the delivery selector handles a missing matching rate. Check the captured browser
and release context against your implementation. The evidence locates an observed failure;
it does not establish its root cause or prescribe an automatic fix.

## Product guides

- Developer evidence: https://docs.dozenfold.com/docs/developer-evidence
- Source maps: https://docs.dozenfold.com/docs/source-maps
- Sessions and journeys: https://docs.dozenfold.com/docs/sessions-and-journeys

The live product's brief is scoped to the selected issue and occurrence. This public example
contains no live investigation link and no financial estimate.