dsh-qr-link

QR codes in both directions for the DeepSeek Harness Web UI: read the link out of an image, or turn any link into a code. Everything runs in the browser session — no upload, no network call, no external binary.

What it does

Decode. Drop, paste or pick an image that contains a QR code and get the payload back with a type badge (link / text / WiFi / email / phone / SMS / contact), plus copy and open actions and a local history. Entry points are drag-and-drop, file picker, Ctrl+V on a screenshot, and an image URL.

Explain. When nothing is found, it does not stop at "no QR code here" — it measures the frame and names the actual problem (see below).

Encode. Type a link or any text and a QR code appears as you type. Error correction L/M/Q/H, 2–24 pixels per module, 0–12 modules of quiet zone, then download as PNG or copy the image to the clipboard.

Why the failure diagnosis exists

jsQR either returns a payload or nothing. For a screenshot that is fine; for a photograph it leaves the user guessing. This plugin measures four properties of the frame and reports what they mean:

Measurement	How it is computed	What it reports
Contrast	standard deviation of luma	code and background blend together
Detail	Laplacian variance on a downscaled copy	frame is blurry, module edges merge
Quiet zone	fraction of dark pixels inside a 2 % border band	the code was cropped into its white margin
Ink coverage	fraction of pixels below mean − 24	light code on a dark background, or an over-dark frame

Eight verdicts come out of this: flat image, too small, low contrast, blurry, cropped quiet zone, dark frame, no dark ink, and generic. The panel prints the raw numbers under the verdict — image 296×296 · contrast 64.6 · detail 3 — so the message is checkable instead of a guess.

The thresholds were tuned against eleven constructed samples: a clean code, the same code with its quiet zone removed, light and heavy Gaussian blur, an inverted code, flat white, flat grey, random noise, a low-contrast code, and a photographic gradient.

What actually improves the hit rate

Before giving up, the decoder retries with two binarizations that jsQR does not attempt on its own: a global Otsu threshold and a block-adaptive one (mean of a local window minus a margin).

Measured: a code rendered at contrast 18.5 (grey-on-grey) fails on raw pixels and is recovered by both binarizations. Uneven lighting, phone screenshots and faded print are the cases this exists for.

Install

dsh plugin --profile web add dsh-qr-link

or straight from the repository:

dsh plugin --profile web add github:392138239-pixel/dsh-qr-link

Then open the QR button in the composer tool row (left side, next to the permission control).

Where it lives in the UI

• a 28 px button in conversation.input.left
• a dialog in shell.overlay with two tabs

Nothing is written outside the plugin's own localStorage key (dsh.qrlink.history.v1, capped at 60 entries).

Privacy

No network requests. Decoding and encoding both happen in the page with bundled JavaScript. An image URL is the only case where the browser fetches anything, and only the URL the user typed.

Compatibility

Requires a DeepSeek Harness build that exposes conversation.input.left and shell.overlay — 0.2.x Web UI. No peer dependencies on @deepseek-ai/* packages: the client half uses the host React from the module table and the host's theme tokens for styling.

Third-party code

Two cores are bundled unmodified into client.js (359 KB total):

Package	Version	License	Use
jsQR	1.4.0	Apache-2.0	decoding
qrcode-generator	1.4.4	MIT	encoding

Full license texts: LICENSE-jsQR.txt, LICENSE-qrcode-generator.txt.

License

MIT — see LICENSE.

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