Jaml Ui

Zero-dependency JSON-to-React engine (json-render) + Balatro card sprite rendering for MCP Apps.

What's inside

• json-render — a tiny, zero-dep JSON-to-React engine in src/json-render. A JsonNode tree + a registry = rendered UI. Ships with a Balatro catalog (Panel, Stack, Grid, SeedCard, SearchStats, JamlGameCard, ...).
• Balatro card sprites — canvas-based JamlGameCard, StandardCard, DeckSprite, plus sprite metadata.
• MCP App example — examples/mcp-seed-finder is a single-file MCP App that talks to an MCP server and renders search results with json-render.

Install

npm install jaml-ui motely-wasm react react-dom

motely-wasm is a peer dependency — boot it once before rendering.

Quick start — render JSON UI

import { render, balatroRegistry } from "jaml-ui";

const spec = {
  type: "Panel",
  props: { title: "Hello" },
  children: [
    { type: "Text", props: { body: "Seed: ALEEB", variant: "title" } },
    { type: "JamlGameCard", props: { type: "joker", card: { name: "Blueprint" } } },
  ],
};

export default function App() {
  return <div>{render(spec, balatroRegistry)}</div>;
}

Boot motely-wasm

motely-wasm ships embedded — the boot resources travel inside the module, so boot() takes no argument.

import bootsharp from "motely-wasm";

if (bootsharp.getStatus() === bootsharp.BootStatus.Standby) await bootsharp.boot();

Boot once per JS realm. Each web worker is its own realm, so a worker fleet boots one engine apiece — see the fleet section in the motely-wasm README for the module-worker and MessagePort rules that keep a worker from hanging.

MCP App example

cd examples/mcp-seed-finder
pnpm install
pnpm dev

Package exports

Scripts

pnpm build      # Vite library build → dist/
pnpm dev        # vite build --watch
pnpm typecheck  # tsc --noEmit
pnpm lint       # ESLint

License

MIT — see LICENSE. Font files in assets/fonts/ are third-party assets by Daniel Linssen; attribution required when redistributing or displaying the pixel fonts.