vercel-labs__json-render/examples/chat

Chat Example

An AI-powered data explorer that streams rich, interactive UI directly into a chat interface. The assistant uses tool calls to fetch real data (weather, GitHub, crypto, Hacker News, web search), then generates a json-render spec that renders inline alongside the conversation using shadcn components, Recharts, and React Three Fiber.

What it shows

• Streaming specs inside chat messages -- pipeJsonRender on the server merges the AI SDK UI stream with json-render spec patches so text, tool-call indicators, and rendered UI all appear in the correct order within a single message bubble.
• ToolLoopAgent with live data -- the agent loops through tool calls (weather, GitHub repos/PRs, crypto prices, Hacker News, web search) to gather real data before generating UI.
• Full catalog/registry stack -- a catalog constrains what the model can produce; the registry maps every component to a real React implementation (shadcn, Recharts charts, R3F 3D scenes).
• State and interactivity -- $state, $bindState, visibility, and actions work inside the streamed spec, so the rendered UI is interactive, not static.

Setup

pnpm install          # from the monorepo root
cd examples/chat
cp .env.example .env.local

Set the required environment variables in .env.local:

Variable	Required	Description
AI_GATEWAY_API_KEY	Yes	Vercel AI Gateway key (auto-authenticated on Vercel)
AI_GATEWAY_MODEL	No	Model identifier, defaults to anthropic/claude-haiku-4.5
KV_REST_API_URL	No	Upstash Redis URL for rate limiting
KV_REST_API_TOKEN	No	Upstash Redis token
RATE_LIMIT_PER_MINUTE	No	Defaults to 10
RATE_LIMIT_PER_DAY	No	Defaults to 100

Rate limiting is a no-op when the Upstash variables are not set.

Run

pnpm dev
# http://chat-demo.json-render.localhost:1355

Requires global portless. The predev script checks for it automatically.

Files

• app/page.tsx -- chat UI with useChat, message rendering, and inline spec display
• app/api/generate/route.ts -- streams the agent through pipeJsonRender with optional Upstash rate limiting
• lib/agent.ts -- ToolLoopAgent with system prompt from explorerCatalog.prompt() and custom rules for layout, 3D, and interactivity
• lib/tools/ -- tool definitions for weather, GitHub, crypto, Hacker News, and web search
• lib/render/catalog.ts -- component catalog (shadcn base + custom metrics, tables, charts, tabs, 3D)
• lib/render/registry.tsx -- maps catalog types to React components (shadcn, Recharts, R3F)
• lib/render/renderer.tsx -- ExplorerRenderer wrapping StateProvider, VisibilityProvider, ActionProvider, and Renderer