Visual Sandbox: A Clickable UI Preview for DeepSeek Harness

Visual Sandbox (Surenkh/dsh-visual-sandbox, maintainer Surenkh, client-side plugin, MIT) is an annotatable UI preview plugin for DeepSeek Harness. It renders workspace HTML or local URLs into the right-side panel, providing four preset frameworks (Responsive, Mobile 390×844, Tablet 768×1024, Desktop 1024×720) and 50%–200% zoom. In "Edit UI," hovering reveals selectors, and clicking fixes the selection to allow adding notes. The plugin organizes elements such as IDs, selectors, outerHTML, bounding boxes, normalized percentages, and computed styles into structured targets for the agent, along with surgical rules that restrict modifications to these targets. It supports version snapshots (8 per session / 8 MB), automatic workspace HTML identification and resource inlining, cross-origin URL bounding box adjustments, and Expand Narrow Containers, offering five tools including `open_visual_sandbox`. Installation requires cloning the repository, adding entries to the profile's `package.json` bundles, running `pnpm install`, and restarting/refreshing. The plugin runs with the permissions of the current DSH process; users should inspect the source code and license before installing.