What this is, and why

A model can describe a comparison, but a wall of Markdown makes the reader do the layout work. This plugin gives the model a small declarative language for the cases where structure carries the answer: side-by-side options, an object you want to inspect, a number the reader will change.

The renderer is a real React tree behind a strict schema. There is no generated HTML, no eval, no shell access, and no page-level JavaScript from the model. Local controls recompute in the browser; the model is only called again when the reader explicitly asks.

In the lab the answer reflows beside the open panel. In Harness the same entity opens as a native right-column tab, so the conversation narrows instead of being covered — see the integration notes.

entity-list layout:"feature" gives a software shortlist a wide preview, the whole description and its sources. Below it, a captioned gallery shows one screenshot at a time.

Metrics, a two-series chart with units and hover, a filterable table with status pills and an ordered flow — one document.

Boxes inside boxes: the pool holds connections, the arrow shows what it talks to. The code block keeps language label, syntax colour and copy.

Sliders recompute the number in the browser; the model is not called again.

390 px: KPI cards in two columns, every chart label, and a table that still fits.

Live demo

rich-ui.beako.best — the real renderer in laboratory conditions, no install. Scenarios: dashboard, films, listing, calculator, configurator, technical breakdown and the rejected-block diagnostic; add &theme=dark for the dark theme. Demo data is illustrative.

Install

Requires DeepSeek Harness 0.2.x and Node 22.19+. No NixOS change, no patched Harness.

dsh plugin --profile web add @kyoukisu/dsh-rich-ui
systemctl --user restart deepseek-harness   # or restart however your Harness runs

From a checkout — this is the loop the author uses:

git clone https://github.com/kyoukisu/dsh-rich-ui && cd dsh-rich-ui
npm ci && npm run build:plugin
dsh plugin --profile web add link:$PWD

Unreleased commits: dsh plugin --profile web add github:kyoukisu/dsh-rich-ui.

The plugin registers itself as a bundle; the fence language is rich-ui.

Quick start

Ask for something that benefits from structure, in a new session:

Compare three electric kettles by price, volume and features. Make it clickable.

The reply arrives as an interface: a summary strip, rows with photos, and a green highlight on the cheapest option. Opening a row shows facts, sources and related items without leaving the conversation.

Things worth trying: "build a budget calculator with three sliders", "show this quarter as a chart and a table", "make a configurator with tabs and conditional warnings".

What it can render

Roughly 150 Lucide icons resolve by name, with semantic tones (success, warning, danger, muted) so colour means something. Light and dark themes follow the host palette and font.

The contract in ten lines

```rich-ui
{"version":1,"title":"Budget","initialState":{"spend":1200},
 "nodes":[
  {"type":"slider","stateKey":"spend","label":"Monthly spend, €","min":100,"max":5000,"step":100},
  {"type":"computed","label":"Per year, €","expr":{"op":"mul","args":[{"state":"spend"},12]}},
  {"type":"callout","tone":"info","content":"Recomputed locally — no model call."}
 ]}
```

{"version":1,"title":"Films for tonight",
 "entities":[{"id":"a","kind":"Film","title":"Arrival","subtitle":"2016 · science fiction",
   "image":"https://example.org/poster.jpg",
   "facts":[{"label":"Director","value":"Denis Villeneuve"}],
   "sources":[{"title":"TMDB","url":"https://www.themoviedb.org/movie/329865-arrival"}],
   "badge":{"label":"Editors' pick","tone":"success"}}],
 "nodes":[
  {"type":"meta","items":[{"icon":"film","text":"3 films"},{"icon":"clock","text":"2 hours"}]},
  {"type":"entity-list","entityIds":["a"]},
  {"type":"table","columns":[{"key":"k","label":"What"},{"key":"v","label":"How many"}],
   "rows":[{"k":"Screenings","v":3}]},
  {"type":"chart","kind":"bar","data":[{"label":"Mon","value":2},{"label":"Tue","value":5}]}]}

The authoritative text is prompt-rich-ui/prompt.md; exact fields, enums and budgets live in references/schema.md, and working documents in references/examples.md.

How it works

flowchart LR
  A["Model writes a rich-ui fence"] --> B["Adapter finds the code block"]
  B --> C{Strict JSON schema}
  C -- invalid --> D["Stays a normal code block"]
  C -- valid --> E["React renderer mounts"]
  E --> F["Local state, no model call"]
  F -- explicit button --> G["rich-ui action message"]

• Node half registers one always-on system-prompt section with the whole contract and the absolute path of the reference files, plus the rich_ui_validate tool. The model can validate the exact JSON before emitting it; a schema error comes back as a tool result, not a visible user message.
• Browser half validates the fence and mounts into a plugin-owned root. While the model is still writing, closed nodes render in an inert preview and become interactive when the block settles.
• A malformed document is never patched in place and never triggers an automatic message: it shows a diagnostic card with the exact error and the rejected JSON, plus a copy button. A browser plugin has no tool channel, so the card deliberately has no "ask the model" button. Unfinished streams stay code until the model closes them.

Safety

Parity with the reference

Measured, not claimed: 19 of 27 reference scenarios reproduced, 2 partial, 6 missing — with an itemised deviation list in docs/PARITY.md. Missing today: Mermaid/ER graphs, math, maps, artifacts, persistent panels and mini-apps.

Known limitation: the fence label is not preserved by Harness, so an unlabelled block is claimed only when its payload looks like a spec document and passes the strict parser. A json-labelled block is never claimed.

Troubleshooting

The block stayed as code. The JSON did not pass the schema — usually an unknown field (title inside a node that has none, or items from another plugin's syntax). A claimed fence shows the exact error and the rejected source, and copies them on request. Nothing is executed, rewritten or sent automatically. The model should call rich_ui_validate before sending; if it did not, ask it to fix the document and validate it.

A rejected block explains itself and copies the exact error and source. Nothing is sent automatically.

Images show a placeholder. The URL is wrong, blocked by the remote host, or not http(s). Ozon/WB CDNs reject hotlinks; use a permitted source or your own media host.

Old dsh-ui messages stopped rendering. That is a different plugin's syntax. This one claims rich-ui only.

Development

npm ci
npm run dev            # lab at http://127.0.0.1:4173, HMR, no Harness needed
npm run build          # typecheck + lab build
npm run build:plugin   # the two real bundle artifacts
npm test               # 217 unit, schema and DOM tests
npm run test:browser   # 58 Playwright desktop + mobile checks (goldens never auto-update)
# Interaction timings: docs/PERFORMANCE.md

Browser tests run in a pinned container so no system libraries are required:

docker run --rm --network host --ipc host --user "$(id -u):$(id -g)" \
  -e HOME=/tmp -v "$PWD:/work" -w /work \
  mcr.microsoft.com/playwright:v1.64.1-noble npx playwright test

Scenarios in the lab: ?demo=dashboard, films, listing, apps, calculator, configurator, technical, primitives, plus &theme=dark.

Screenshots in this README are captures of that lab, not mockups. Golden images under tests/ are regression baselines and say nothing about fidelity to another product.

License

MIT — see LICENSE. Demo photography comes from Wikimedia Commons under free licences; prices and metadata are illustrative. DeepSeek Harness is a separate project by DeepSeek; this plugin is unaffiliated. ChatGPT is a trademark of OpenAI: the description points at the style of rich answers, not at any affiliation, endorsement or shared code.