GGUI

🚧 Public preview — pre-1.0. All 32 @ggui-ai/* packages ship in lockstep minor waves — the badges below show the current one; the protocol is a draft and may still change between waves. Pin exact versions (see badges below) and watch Releases for each wave's notes; v1.0 marks the protocol freeze.

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Agents describe what they need in natural language; GGUI generates ephemeral, interactive interfaces over MCP. No frontend code, no React templates, no custom components — agents talk, users see UI.

This repo is the open protocol + reference runtime. Self-host with ggui serve; pair against any MCP-aware agent runtime (Claude Desktop, Claude Code, claude.ai, Cursor, ChatGPT desktop, Goose, your own). Zero account required, zero managed infrastructure required, zero cloud dependency.

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Quick start — pick your path

1. Composed golden path — platform-composed (guuey-sdk)

One flow from a guuey.json to a rendered, interactive todo UI — every piece a published SDK. guuey's dev tooling runs the agent (@guuey/cli + @guuey/worker), the GGUI runtime is the dev router's injected MCP default, and the web client talks to the router with @guuey/agent-client. This path is platform-composed: it drives the GGUI protocol through guuey's published SDKs. The protocol itself has no guuey dependency — paths 2–4 run without it, and the framework-native samples (path 2) stay first-class.

Prerequisites: Node.js 22+, pnpm, and an ANTHROPIC_API_KEY (one key drives both the agent and GGUI's UI generation).

git clone https://github.com/ggui-ai/ggui && cd ggui
pnpm install                        # workspace deps — `guuey dev` spawns the colocated
                                    # todo MCP from samples/mcp-servers/todo
export ANTHROPIC_API_KEY=sk-ant-…   # in every terminal below

# terminal 1 — the ggui runtime MCP (guuey's dev router injects ggui → this port).
# --dev-allow-all admits the bearer-less local callers (the router's ggui
# connection and the web page's relay). Local dev only.
npx -y @ggui-ai/cli serve --mcp-only --dev-allow-all   # http://127.0.0.1:6781/mcp

# terminal 2 — the agent half: guuey.json + a Claude agent worker
cd samples/agents/with-guuey
npm install
npm run dev                              # guuey dev --serve → http://localhost:6790

# terminal 3 — the web half: chat + rendered ggui cards
cd samples/apps/with-guuey-web
npm install
npm run dev                              # http://127.0.0.1:6890

Browser-based clients. Pages served from localhost reach the MCP endpoint out of the box. A page on any other origin — a deployed site, an Electron renderer — must be allowlisted:

ggui serve --browser-origin https://app.example.com

(repeatable; or GGUI_BROWSER_ORIGINS=a,b). The allowlist drives both MCP-wire Origin validation and the CORS response headers, so one flag covers both. It is not authentication: it does not change the bearer check on /mcp. Non-browser clients (Claude Desktop, agents, curl) are unaffected: they connect server-to-server and ignore CORS entirely.

Open http://127.0.0.1:6890 and ask for your todos: the agent calls the todo MCP, renders an interactive todo UI through GGUI, and your clicks flow back to the agent. Per-sample detail (ports, env vars, known limitations): samples/agents/with-guuey · samples/apps/with-guuey-web. Prefer a scaffolded start? npx @guuey/create-agentic-app scaffolds a guuey agentic app of the same shape (agent + MCP + GGUI + web) in one command.

Dev-server trust: guuey dev runs your agent unjailed with your environment — standard dev-server trust; run it in a container if that posture doesn't fit.

2. Bring your own framework — build from the framework-native samples

The framework-native path to ship an agent end-to-end — no guuey dependency. The canonical samples are complete, runnable pieces of an agentic app — an agent backend per SDK, a stock GGUI server config, a reference MCP server, and a web client. Compose them into a workspace and run the whole thing:

git clone https://github.com/ggui-ai/ggui && cd ggui

# your app = four samples composed into one pnpm workspace:
#   samples/agents/<sdk>/        → servers/agent/     (claude-agent-sdk | openai-agents-sdk | google-adk)
#   samples/gguis/default/       → servers/ggui/      (stock `ggui serve` config)
#   samples/mcp-servers/todo/    → servers/mcps/todo/ (reference domain MCP)
#   samples/apps/ggui-basic-web/ → apps/web/          (Vite + React chat client)
# (e2e/samples-render/app-shell/ is the reference root wrapper — package.json
#  with the dev scripts + pnpm-workspace.yaml + the `pnpm dev` orchestrator.)

pnpm install
# put your LLM API key in .env.local, then:
pnpm dev                     # starts ggui + MCP servers + agent + web, then opens the app

pnpm dev brings all four services up together and opens http://localhost:6890 once it's ready — so you never have to guess which port to visit (server logs are hidden by default; pnpm dev --verbose streams them). The full loop runs locally: you type → the agent calls domain tools and renders a React UI → you click in that UI → the agent reacts. Each sample carries its own README with standalone run instructions.

Building a hosted agent instead? See guuey.com — the managed platform for running agents (not a drop-in replacement for the samples path).

3. Self-host the OSS MCP server + test from claude.ai

For testing the GGUI protocol against a real chat host. Localhost won't work from claude.ai — you need a public HTTPS URL, which cloudflared provides for free.

# terminal 1 — a public HTTPS URL for port 6781 (no Cloudflare account needed)
cloudflared tunnel --url http://127.0.0.1:6781     # prints https://<random>.trycloudflare.com

# terminal 2 — boot the OSS MCP server behind that URL
npm install -g @ggui-ai/cli
ANTHROPIC_API_KEY=sk-… ggui serve --mcp-only --oauth \
  --public-base-url https://<random>.trycloudflare.com   # banner prints the pair code

Browser-based clients. Pages served from localhost reach the MCP endpoint out of the box. A page on any other origin — a deployed site, an Electron renderer — must be allowlisted:

ggui serve --browser-origin https://app.example.com

(repeatable; or GGUI_BROWSER_ORIGINS=a,b). The allowlist drives both MCP-wire Origin validation and the CORS response headers, so one flag covers both. It is not authentication: it does not change the bearer check on /mcp. Non-browser clients (Claude Desktop, agents, curl) are unaffected: they connect server-to-server and ignore CORS entirely.

--oauth lets claude.ai connect without a pre-shared bearer, and --public-base-url makes the server answer on the tunnel host and hand claude.ai URLs it can reach. Then in claude.ai → Settings → Connectors → Add custom connector, paste https://<random>.trycloudflare.com/mcp and leave the OAuth Client ID and Secret empty (the server uses Dynamic Client Registration). Click Connect: your server's consent page asks for the pair code from the ggui serve banner. The code works once and expires after about 10 minutes; restart ggui serve for a fresh one. Ask Claude to render any UI; the server generates the component and serves it back as a rich rendered card inside the chat.

Install cloudflared via your package manager: brew install cloudflared (macOS), apt install cloudflared (Debian), or grab a binary from cloudflare.com/products/tunnel.

4. Use the hosted GGUI cloud — mcp.ggui.ai

To skip self-hosting, use the hosted service (Public preview): sign in at the GGUI console → create an app → mint a connector key. Paste the bare https://mcp.ggui.ai endpoint into your chat host's connector settings — no tunnel, no server to run.

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The ggui CLI

@ggui-ai/cli ships the ggui binary — the single entrypoint for every OSS workflow. Five verbs cover the core workflow:

Verb	What it does
ggui serve	Boot the OSS MCP server (/mcp), session viewer (/r/<shortCode>), pairing endpoints, and live-channel WebSocket. --mcp-only skips agent supervision — fastest first-run. --port, --host adjust binding.
ggui dev	Local UI registry + compile-on-demand dev hub for iterating on a ggui.json project. Optional tunnel, agent supervision, browser auto-open. Run ggui --help for the full flag list.
ggui blueprint	Author + publish + install cached UI templates — create, publish, install. Blueprints make a known screen cheap, repeatable, and visually consistent by matching before falling back to full LLM generation.
ggui gadget	Author + publish + install client-side libraries (maps, charts, camera, clipboard, anything) wrapped as GGUI hooks/components so the generator can use them — create, publish, install.
ggui theme	Validate and inspect ggui.json#theme DTCG documents — ggui theme validate <path>. Catches schema errors before they reach the runtime.

Plus auth verbs for the hosted path: ggui login / ggui logout / ggui whoami / ggui keys. Run ggui --help for the top-level overview, or ggui <verb> --help for per-command flags.

Full CLI reference: @ggui-ai/cli README.

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Runnable examples

samples/ holds end-to-end examples you can clone:

• samples/gguis/ — ready-to-run project configs (default, leaflet-demo, mapbox-demo, canvas-demo) showing how a ggui.json is shaped.
• samples/agents/ — framework-native reference agents per SDK (Claude Agent SDK, OpenAI Agents SDK, Google ADK) talking to GGUI as an MCP server.
• samples/agents/with-guuey + samples/apps/with-guuey-web — the platform-composed (guuey-sdk) golden-path pair: a guuey.json Claude agent served by @guuey/cli's dev router, and a web client on @guuey/agent-client rendering GGUI cards (see path 1 above).
• samples/gadgets/ — example component / hook gadgets for the marketplace.
• samples/mcp-servers/ — minimal domain MCP servers (e.g. a todo server) you can pair against.

Honest scope today

• ✅ Local server, viewer, cookie-authenticated WebSocket subscribe → ack all work end-to-end.
• ✅ ggui_render mints shortCodes and lands on the same-origin viewer.
• ✅ Component-code generation is wired on the OSS path via createUiGenerator() from @ggui-ai/ui-gen (the same harness the hosted runtime uses). When no BYOK credentials resolve (no ANTHROPIC_API_KEY / OPENAI_API_KEY / etc.), ggui_render returns an isError: true tool result whose structuredContent.error.code is NO_CREDENTIALS; supply a key to get full generation locally.
• 🔒 ggui serve defaults to strict pairing: only pair-minted bearers reach /mcp (--dev-allow-all admits any bearer, or none, for local dev only). Embedding createGguiServer() without an auth option admits any bearer, or none, as builder; pass a real AuthAdapter via createGguiServer({ auth }) before exposing it beyond 127.0.0.1.

How it works

┌─────────┐     MCP Tools      ┌──────────┐     WebSocket     ┌──────────┐
│  Your   │ ────────────────→  │  ggui    │ ────────────────→ │  User's  │
│  Agent  │   ggui_render      │  server  │   real-time UI    │  browser │
│         │   ggui_update      │          │   updates         │          │
│         │ ←────────────────  │          │ ←──────────────── │          │
│         │   user events      │          │   clicks, forms   │          │
└─────────┘                    └──────────┘                   └──────────┘

Your agent uses MCP tools to push UIs and receive user events. The protocol is defined by @ggui-ai/protocol; the reference server lives in @ggui-ai/mcp-server; embedding host-helpers ship in @ggui-ai/mcp-apps-react (web) and @ggui-ai/mcp-apps-react-native (React Native).

MCP tools (primary surface)

Tool	Description
ggui_render	Render a UI for the user (natural-language prompt + data)
ggui_update	Update props on an existing UI (no regeneration, ~200ms)
ggui_handshake	Initial session bootstrap
ggui_consume	Long-poll for user gestures (clicks, form submits)

Plus a blueprint family (ggui_search_blueprints, ggui_render_blueprint, ggui_list_featured_blueprints, …) for catalogue lookups. Full reference: MCP Protocol Reference.

Zero agent code (MCP config only)

If your agent runtime supports MCP natively, skip the SDK entirely. Run ggui serve --dev-allow-all for local development and add it as an MCP server:

{
  "mcpServers": {
    "ggui": {
      "url": "http://127.0.0.1:6781/mcp",
      "headers": { "Authorization": "Bearer dev" }
    }
  }
}

--dev-allow-all accepts any bearer, so dev is a placeholder. Without the flag, ggui serve admits only pair-minted bearers: pair with the code on its boot banner (landing page or POST /pair) and put the token you receive in place of dev.

The runtime's native tool-calling loop discovers ggui_render, ggui_update, ggui_consume, and the blueprint catalogue tools directly. Working examples per framework: Claude, OpenAI, Gemini, generic MCP.

Embedding UIs

On web, <AppRenderer> — imported directly from @mcp-ui/client, the spec-canonical MCP Apps host — is the canonical consumer primitive, driven by GGUI's useMcpAppsChat hook from @ggui-ai/mcp-apps-react. <AppRenderer> mounts each GGUI render inside a sandboxed iframe; the iframe owns the WebSocket lifecycle and renderer bundle, so host code never touches render internals or WebSocket machinery directly.

npm install @ggui-ai/mcp-apps-react @mcp-ui/client

import { AppRenderer } from "@mcp-ui/client";
import { useMcpAppsChat } from "@ggui-ai/mcp-apps-react/chat-helpers";

function Chat({ agentUrl, sandboxUrl }: { agentUrl: string; sandboxUrl: string }) {
  const { sessions, send, handleAppMessage } = useMcpAppsChat({
    chatEndpoint: `${agentUrl}/agent`,
  });

  // render `entries` as chat bubbles; call send(prompt) to talk to the agent.
  // onReadResource / onCallTool relay through your agent backend — see the
  // full runnable reference below for the wiring.
  const latest = sessions[sessions.length - 1];
  return latest ? (
    <AppRenderer
      toolName="ggui_render"
      sandbox={{ url: new URL(sandboxUrl) }}
      html={latest.inlinedResource?.text}
      onMessage={handleAppMessage}
      onError={(err) => console.warn("render error", err)}
    />
  ) : null;
}

The complete runnable reference — including auth, sandbox relay, and tool-call wiring — is the ggui-basic-web sample. Start there.

React Native's equivalent host is <McpAppIframe> from @ggui-ai/mcp-apps-react-native — RN-only; there is no <McpAppIframe> on web.

Implementer references for the full protocol: React host helpers, Architecture overview, MCP Apps support, WebSocket protocol.

For non-React frameworks, embed the viewer directly:

<iframe src="http://127.0.0.1:6781/r/{shortCode}" width="100%" height="600"></iframe>

Packages

Consumer-facing surface — what you npm install:

Package	Purpose	npm
@ggui-ai/cli	The ggui binary — serve, dev, blueprint, gadget, theme
@ggui-ai/mcp-server	Reference OSS server (programmatic embedding)
@ggui-ai/mcp-apps-react	React web host helpers — useMcpAppsChat + MCP-Apps chat hook
@ggui-ai/mcp-apps-react-native	React Native host helpers — <McpAppIframe> MCP-Apps host + shells
@ggui-ai/protocol	Wire types (events, sessions, WebSocket, MCP envelopes)
@ggui-ai/gadgets	Author wrappers for 3rd-party libs (Leaflet, Mapbox, …)

Plus 26 supporting packages under packages/ spanning the runtime (@ggui-ai/mcp-server-core, @ggui-ai/mcp-server-handlers, @ggui-ai/ui-gen, @ggui-ai/negotiator), authoring (@ggui-ai/project-config, @ggui-ai/ui-registry), registry (@ggui-ai/registry-core, @ggui-ai/registry-server), and dev tooling (@ggui-ai/dev-stack, @ggui-ai/agent-runtime, @ggui-ai/console). See each subdirectory for details.

Hosted providers

Self-hosting is the primary path. For managed infrastructure (no server to run, no LLM key to wire, hosted dashboards), the first-party hosted endpoint at mcp.ggui.ai is live — see path 4 above. Guuey hosts an upgraded experience built on top of the protocol. The protocol is identical on all paths — you can move between self-hosted and hosted without rewriting anything against this SDK.

Contributing

See CONTRIBUTING.md. Issues + PRs welcome.

License

Apache 2.0 — see LICENSE.