DeepSeek Harness Background

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A custom background image plugin for the DeepSeek Harness Web GUI (dsh web): upload a local picture, or paste an image URL, and render it behind the whole app surface with adjustable opacity, readability scrim, panel transparency and frosted-glass blur — everything live-previewed inside the settings panel and committed automatically on release.

The look (fixed wallpaper layer + theme-aware scrim + translucent glass panels driven by --dsw-* design tokens) is modeled on the community dsh-wallpaper-engine implementation.

Screenshots

Home
Conversation
Settings

Features

• Local upload — pick a JPG / PNG / WebP / GIF from your computer; the plugin stores it under the harness home and serves it over a same-origin route (admitted only when the declared MIME, detected signature and extension all agree).
• Paste a URL — drop an http(s) image link and press Enter.
• In-panel live preview — a preview surface at the top of the row renders the image + scrim + a frosted glass bubble; dragging any slider repaints it instantly.
• Stepped sliders — ratio controls snap in 5% steps, blur radii in 1/2px steps; dragging only repaints, release commits (one write per gesture, no jank).
• Five controls — wallpaper opacity, readability scrim, panel opacity, frosted-glass blur, and wallpaper blur.
• Fit modes — cover (fill, crop) or contain (whole image).
• Theme-aware scrim — the light theme uses a white veil (lifts the art so dark text keeps contrast); the dark theme automatically switches to a black veil (dims the art so light text keeps contrast).
• Frosted glass (whitelisted) — while a background is active, only the surfaces that float as small cards over the wallpaper turn into translucent glass (specular sheen + backdrop-filter): the composer card and message bubbles, code blocks / terminal / diff / tool-IO cards / skill & MCP call cards and inline code, the agent task strips and their takeover panels (approval / question / plan review), the chrome buttons (new session, composer plus, scroll-to-bottom), the load-earlier history button, the subagent lineage popover, the sidebar build badge, and the home hero "preview" badge — every glassed surface carries the full recipe (fill + sheen + blur), never translucency without frost. Reading surfaces — dialogs, the settings UI, menus, tooltips, toasts, hover fills and every accent (the send button stays blue) — keep their official opaque paints so nothing legible turns washy. The blur radius is driven by the glass-blur slider; panelOpacity at 100% restores the official paints on the whitelisted list too.
• Third-party glass registry — any plugin can register its own panels into the same frosted-glass system through the published bridge (window.__DSH_BACKGROUND_GLASS__ global + the dsh-background-glass:ready event): token mode adds the missing sheen + blur chain when the panel already fills with an overridden --dsw-* token, fill mode takes the fill over as well; every rule sits under the data-dsh-bg-glass gate so it toggles with the glass automatically. Consumers take zero dependencies and degrade gracefully when this plugin is absent; the whole bridge tears down with it. See docs/GLASS_API.md.
• Conversation timeline — a DeepSeek-web-style scroll-navigation rail at the right edge of long conversations: one tick per user message on a frosted capsule; hovering expands it into a frosted panel listing every question (active one highlighted in brand blue); clicking jumps the chat to that message with a smooth glide (ease-in-out, distance-paced; the bottom-follow state is detached from the official 25px follow zone one frame before the slide, so streaming growth / turn-end re-renders cannot yank it back to the floor; wheel, touch or keyboard scrolling takes over instantly mid-glide, and prefers-reduced-motion places directly). Key-point bookmarks — star a question in the expanded panel (persisted per session): marked questions show a golden tick in the collapsed capsule and a "★ marked only" filter narrows the list. Jumps freeze the reading-position tracker until scrolling settles (no mid-jump jitter), and messages withdrawn by a rewind are dropped from the rail automatically (the target parser accepts seq 42 / #42 / english-chinese verb forms plus structured fields, and recognizes third-party data-dsh-rewind-hidden node markers). Collapsed and expanded share one identical height (no jump); idle ticks are bottom-pinned — the newest question's tick hugs the capsule's bottom edge like the official nav, fed by the full-session history regardless of how much of the conversation the chat view has paged in — and the expanded panel's clipped edges get the official 32px fade veils. While the background glass is on, the rail joins the same unified glass recipe as the composer card and bubbles (fill follows panel opacity, blur follows the glass-blur slider); without glass it keeps the official DeepSeek frosted paints. Toggle it off with the timeline switch in the row. If the third-party dsh-chat-timeline plugin is also installed, this rail steps aside instead of doubling it.
• Persisted in the official settings document ($DSH_HOME/settings.yaml), waits out restarts.
• Clean teardown — disabling, clearing or uninstalling restores the original background exactly; the plugin only ever removes what it wrote.

Install

The plugin is a standard out-of-tree dsh bundle, published on npm:

dsh plugin --profile web add deepseek-harness-background

From a local checkout (development):

dsh plugin --profile web add /path/to/deepseek-harness-background

From a source checkout:

pnpm dsh plugin --profile web add /path/to/deepseek-harness-background

Or from git:

dsh plugin --profile web add github:<you>/deepseek-harness-background#<commit>

Restart to load it:

dsh --profile web

Usage

1. Start the Web UI (dsh --profile web) and open it in a browser.
2. Open Settings (bottom-left) → General → the Custom Background row (in the same area as the Appearance row).
3. Upload an image or paste a URL — the background applies immediately and the preview surface above updates in sync.
4. Tune the controls — sliders snap in steps and commit on release:

5. 清除背景 removes the background and restores the stock look.

How it works

• The settings row lives in the official General settings section (settings.general.item slot), next to the Appearance row. Its chrome uses only --dsw-alias-* design tokens (buttons / pills / segmented control / slider track match the official shell); sliders are native input[type=range] with 5% / 1–2px steps and release-commit.
• The plugin's own host routes (/api/bg-wallpaper/*: settings, upload, image/<id>) read/write the section and serve uploads with same-origin + size caps + MIME/signature checks + a path-escape fence. A custom route family is used because the api-proxy settings allowlist does not expose third-party namespaces over the settings RPC.
• The background is drawn as a fixed z-index:-2 wallpaper layer plus a z-index:-1 scrim on body, toggled by the data-dsh-bg attribute; the scrim switches white/black by data-ds-dark-theme in the injected stylesheet. Frosted glass is whitelist-scoped: only the whitelisted surfaces get --dsw-* surface-token overrides, while everything else is painted by explicit data-dsh-bg-glass-gated rules carrying the FULL recipe (fill + sheen + blur chain): the three chrome buttons, the load-earlier history button, the composer dock family (agent task strips TodoPanel / GoalBar / QueueDock and their takeover panels — approval, question, plan review — whose tokens turn translucent and need the blur added), the subagent lineage popover, the home hero preview badge and the sidebar build badge — every other official token and reading surface (menus, dialogs, tooltips, toasts) stays untouched.
• The timeline rail is registered into the conversation.input.dock slot (per-session lifecycle) and portals to body. Its data comes, fastest first, from a host-side session projection (bgTimeline, registered in src/projection.ts) that enumerates every user message of the whole session — including turns the conversation has not paged in yet — with the loaded chat-node window as fallback. The conversation's own lazy loading is never driven by the rail (jumping to an old message pages history on demand, exactly like clicking "load earlier"); bookmarks persist in localStorage per session. Idle (collapsed), the tick stack is pinned to the capsule's bottom edge — the newest question's tick always hugs the bottom, older ones clip at the top — matching the official ScrollNav; hovering expands and follows the reading position instead. The official DeepSeek frosted paints are the no-glass fallback — under data-dsh-bg-glass the rail joins the plugin's unified recipe (composer fill token + the glass-blur slider chain), exactly like the chrome buttons, code cards and the composer itself.
• The third-party glass registry (src/client/glass-registry.ts) publishes its bridge on client apply — before any repaint can race it: register({ plugin, selectors, mode }) is idempotent per (plugin, mode, selector) triple and synthesizes explicit body[data-dsh-bg-glass]-gated recipe rules into a dedicated <style data-plugin-css> tag; selectors are structurally validated first (no { } ; @ < > ,, no backslashes, 500-char cap) with per-selector warn-and-drop that never blocks valid siblings; disposing the client fiber retracts the whole bridge (stylesheet, entries, window key). Contract docs in docs/GLASS_API.md / GLASS_API.zh.md; behavior locked by tests/glass-registry.spec.ts.
• Uploads live under $DSH_HOME/deepseek-harness-background/ (content-addressed ids). Switching to a new image or clearing the background deletes the superseded upload file, so the directory does not accumulate dead images in normal use. (An upload that is never saved into the section — e.g. the tab closes right after an upload — can leave one orphaned file behind.) Disable / uninstall leaves nothing behind.

Development

pnpm install          # first time; runs prepare (build)
pnpm run typecheck    # tsc
pnpm test             # vitest contract tests
pnpm run build        # tsdown: lib/index.js (host) + lib/client.js (browser bundle)

deepseek-harness-background/          # the plugin repo (package name stays the npm-style id)
├── package.json          # dsh.bundle.patch + dsh.client.inject declarations
├── cordis.patch.yml      # inserts the deepseek-harness-background row into the web roster
├── tsdown.config.ts      # official clientBundle preset
├── src/
│   ├── index.ts          # host half: ui-background namespace + API routes
│   ├── routes.ts         # /api/bg-wallpaper/{settings,upload,image/<id>}
│   ├── schema.ts         # host-side schemastery schema
│   ├── settings.ts       # constants/types shared with the client
│   ├── projection.ts     # bgTimeline session projection (full user-message index for the rail)
│   ├── harness-home.ts   # $DSH_HOME / ~/.dsh resolution
│   └── client/
│       ├── index.ts          # painter lifecycle + settings row registration
│       ├── backdrop.ts       # fixed wallpaper layer + scrim + glass surface + preview vars
│       ├── background-css.ts # injected stylesheet (layers, glass, light/dark scrim, variables)
│       ├── glass-registry.ts # third-party glass registry (window bridge + gated rule synthesis)
│       ├── timeline.tsx     # conversation timeline rail (ScrollNav port on the glass system)
│       ├── timeline-css.ts  # timeline stylesheet (dsbt- prefixed, official metrics)
│       ├── SettingsRow.tsx   # the General-settings row (preview surface + stepped sliders)
│       ├── SettingsRow.module.css # row styles (official tokens)
│       ├── settings-client.ts# fetch transport (read/write/upload)
│       └── locales.ts        # zh/en copy
└── tests/                  # schema, routes, apply (painter), settings-row contracts

License

MIT