Scanning

Capture

The scanner in components/Scanner.tsx has two modes. demo preloads a catalog object and plays the scan sequence. full opens the camera on phones (getUserMedia, rear camera) and accepts a file on everything else. Either way you end with a Blob.

On /scan you can also pass ?slug= to preload a catalog object through GET /api/identify, so the demo and the real thing share one code path.

Downscale

Before anything leaves the browser the image is drawn onto a canvas at most 1280px on its long side and re-encoded as JPEG at quality 0.85. A 12 MP photo becomes a few hundred kilobytes. That keeps the request fast and keeps well under the server cap of MAX_IMAGE_BYTES (8 MB), which returns 413 if exceeded.

const max = 1280;
const scale = Math.min(1, max / Math.max(img.naturalWidth, img.naturalHeight));
canvas.width  = Math.round(img.naturalWidth * scale);
canvas.height = Math.round(img.naturalHeight * scale);
ctx.drawImage(img, 0, 0, canvas.width, canvas.height);
return canvas.toDataURL("image/jpeg", 0.85);

The request

The data URL goes to POST /api/identify as { image }. The route runs on Node with a 60 second budget (maxDuration = 60). It loads the live symbol list and display names from the registry (cached one hour), calls identifyObject, then resolveBasket, and answers with { basket }.

The prompt hands the model every live ticker with its short name, one per line, and tells it to use those verbatim. A ticker that is not on the list cannot be in the basket. It goes to unlisted with the reason Not tokenized on Robinhood Chain.

Model fallback chain

modelChain() in lib/ai.ts builds the list at request time. Every candidate is tried in order; any error moves to the next one. The first model that returns valid structured output wins, and the route logs which one answered.

Auth for the gateway is the Vercel OIDC token: VERCEL_OIDC_TOKEN in .env.local when running locally (pulled with vercel env pull), automatic on Vercel. Every call uses temperature 0.2, maxOutputTokens 1500, one retry and a 45 second abort, so a throttled chain still fails inside the route budget.

Rejections

The schema has a notAnObject flag. A face, a landscape, a screenshot or a blank frame sets it, and the route returns 422 with the model's one-line reason. A 422 is an answer, not a failure: it does not trigger the next model.

What is kept

Next: how the weights in that basket are meant to be read. Supply-chain weighting.