UPAY3FOOD.agent — browser extension

Reads the iFood page the user is on (read-only), detects the page context, extracts the order, records a MarketObservation locally and compares the checkout with recent comparable observations.

#Run

pnpm install
pnpm build:extension   # → apps/extension/dist

Chrome → chrome://extensions → Developer mode → Load unpacked → apps/extension/dist.

#Page contexts

SEARCH_RESULTS · RESTAURANT · PRODUCT · CART · CHECKOUT · PIX_PAYMENT · ORDER_CONFIRMATION · UNKNOWN — detected from URL hints + visible pt-BR labels (src/content/context.ts). The popup header shows the context; hover it to see the signals that fired.

#Extraction

• Order-summary container. Every element that is the nearest ancestor of a "Subtotal" label holding a "Total" label is a candidate. Candidates that are not on screen (off-canvas drawers, opacity: 0, inert, hidden) are rejected. Among the rest, the one whose nearest call-to-action matches the context wins ("Fazer pedido" at checkout, "Escolher forma de pagamento" in the bag). Several on-screen candidates with different totals → the quote is invalid (ambiguous), never guessed.
• Fees are bound to their labels inside that container; struck-through prices are ignored; "Grátis" = R$0,00; "Cupom …"/"Desconto …" rows are read as a positive discount; absent optional rows are assumed R$0,00 (low).
• Validity gate. A quote is valid only if subtotal + delivery + service − discount = total exactly and the item lines (quantity: 2x, 2 x, 2×, x2, 2 un.) add up to the subtotal (line totals, or unit price × qty). Invalid quotes are shown as Not validated, never recorded, never sent to the decision engine; no item price is ever shown in place of a total.
• SPA. The content script re-extracts on DOM, attribute (class, style, hidden, aria-*) and route changes (400 ms debounce, 2 s max wait). Each new valid state of the same cart (same observer + source + merchant, 60 min) replaces the previous one in storage. Out-of-order snapshots are ignored.
• The popup always requests a fresh extraction from the page (GET_SNAPSHOT); it never displays cached background state as the current checkout.

#Debug mode

Settings → Debug mode: extraction timestamp, snapshot id, observedAt, context signals, chosen/rejected summary containers, validity reasons and the DOM evidence of every field. Capture order DOM exports the structure of the summary containers (scrubbed of e-mails, phones, CEPs, long numbers and addresses — review before sharing) to calibrate against real iFood markup.

#Privacy & safety

• Never modifies iFood's DOM. The badge lives in a closed Shadow DOM on its own <upay3food-agent-badge> element.
• Never reads cookies, storage, tokens or network traffic; never automates checkout or payment.
• Observations are stored in chrome.storage.local. Upload happens only if the user sets an endpoint (permission requested at runtime; credentials: "omit").

#Known limitations

• Labels, CTAs and URL hints are assumptions modelled on iFood web and tested on synthetic HTML (test/fixtures), including the regression checkout-stale-drawer.html (bag drawer left mounted off-screen after the SPA transition). They have not been verified against real iFood markup: use Debug mode → Capture order DOM on a real checkout and add it as a fixture.
• Only açaí with a known volume is compared.
• Discount scope (public vs account-specific) cannot be seen; recorded as unknown.