Custom UI (rootComponent)

The rootComponent is a virtual filesystem of React/TSX files that run in a sandboxed iframe. It provides the world's visual layer and has full access to game state, chat control, session management, AI completions, and audio.

rootComponent Schema

{
  "rootComponent": {
    "id": "uuid",
    "name": "My World UI",
    "entryFile": "index.tsx",
    "files": {
      "index.tsx": "export default function App() { ... }",
      "bubble.tsx": "export default function Bubble({ content, role }) { ... }"
    },
    "updatedAt": "2024-01-01T00:00:00Z"
  }
}

Entry Point

index.tsx must export a default component:

export default function App() {
  return <Chat />;
}

With custom message bubbles:

import Bubble from "./bubble";

export default function App() {
  return <Chat renderBubble={Bubble} />;
}

Full app mode:

export default function App() {
  var api = useYumina();
  
  return (
    <div style={ {display: "flex", flexDirection: "column", height: "100vh"} }>
      <header>HP: {api.variables.health}</header>
      <MessageList />
      <MessageInput />
    </div>
  );
}

useYumina() — Complete API Reference

State Reads

interface SandboxedYuminaAPI {
  // Game state
  variables: Record<string, unknown>;
  globalVariables: Record<string, unknown>;
  
  // World info
  worldName: string;
  worldId: string;
  sessionId: string;
  
  // User identity
  currentUser: { id: string; name?: string; image?: string | null } | null;
  user: { name: string; avatar: string | null };  // Persona-aware
  
  // Chat state
  messages: SandboxMessage[];
  isStreaming: boolean;
  streamingContent: string;
  streamingReasoning: string;
  pendingChoices: string[];
  error: string | null;
  readOnly: boolean;
  
  // Lorebook
  entries: ReadonlyArray<SandboxEntry>;
  getEntry(name: string): SandboxEntry | null;
  
  // Session
  checkpoints: Array<{ id: string; name: string; messageCount: number; createdAt: string }>;
  greetingContent: string | null;
  mode: "session" | "guest-preview";
  capabilities: {
    canSendMessage: boolean;
    canPersistSession: boolean;
    canUseSessionApis: boolean;
    requiresAuth: boolean;
  };
  
  // UI state
  canvasMode: "chat" | "custom" | "fullscreen";
  selectedModel: string;
  userPlan: string;
  preferredProvider: "official" | "private";
  language: string;
  bgmVolume: number;
  sfxVolume: number;
}

Chat Actions

sendMessage(text: string): void;
editMessage(messageId: string, content: string): Promise<boolean>;
deleteMessage(messageId: string): Promise<boolean>;
regenerateMessage(messageId: string): void;
continueLastMessage(): void;
stopGeneration(): void;
restartChat(): void;
swipeMessage(messageId: string, direction: "left" | "right"): Promise<Record<string, unknown>>;
setComposerDraft(text: string): void;
clearPendingChoices(): void;

Session Management

revertToMessage(messageId: string): Promise<void>;
branchFromMessage(messageId: string): Promise<string | null>;
getBranchContext(): Promise<BranchContext>;
createSession(worldId: string): Promise<string>;
deleteSession(sessionId: string): Promise<void>;
listSessions(worldId: string): Promise<Array<Record<string, unknown>>>;
navigate(path: string): void;

Checkpoints

saveCheckpoint(): Promise<void>;
loadCheckpoints(): Promise<void>;
restoreCheckpoint(checkpointId: string): Promise<void>;
deleteCheckpoint(checkpointId: string): Promise<void>;

AI Completions

ai.complete(params: {
  messages: Array<{ role: string; content: string }>;
  onDelta?: (text: string) => void;
  model?: string;
  maxTokens?: number;
  temperature?: number;
  includeLorebook?: boolean | "all" | "matched";
}): Promise<string>;

Make raw LLM calls with optional streaming and lorebook injection. Use for NPC generators, dynamic descriptions, hint systems, or any AI logic outside the main chat flow.

Game Actions

setVariable(id: string, value: unknown, options?: {
  scope?: string;
  targetUserId?: string;
}): void;
executeAction(actionId: string): void;
injectContext(message: string, options?: { role?: "system" | "user" }): void;

Audio

playAudio(trackId: string, opts?: {
  volume?: number;
  fadeDuration?: number;
  chainTo?: string;
  maxDuration?: number;
  duckBgm?: boolean;
}): void;
stopAudio(trackId?: string, fadeDuration?: number): void;
setAudioVolume(type: "bgm" | "sfx", volume: number): void;
getAudioVolume(type: "bgm" | "sfx"): number;

Storage (World-Scoped, Persistent)

storage.get(key: string): Promise<string | null>;
storage.set(key: string, value: string): Promise<void>;
storage.remove(key: string): Promise<void>;

UI Controls

toggleImmersive(): void;
switchGreeting(index: number): void;
copyToClipboard(text: string): void;
showToast(message: string, type?: "success" | "error" | "info"): void;
resolveAssetUrl(ref: string): string;
renderMarkdown(text: string): string;

Model Selection

setModel(modelId: string): void;
getModels(): Promise<{
  models: Array<{ id: string; name: string; provider: string; contextLength: number }>;
  pinnedModels: string[];
  recentlyUsed: string[];
}>;
pinModel(modelId: string): void;
unpinModel(modelId: string): void;
setPreferredProvider(provider: "official" | "private"): Promise<{
  ok: boolean;
  provider?: string;
  error?: string;
}>;

Built-In Components

Available as globals — no imports needed. Import statements are silently stripped at compile time, so both styles work, but the components are injected into scope automatically:

// These are already in scope — just use them directly:
// Chat, MessageList, MessageInput, ChatCanvas,
// ModelPickerModal, ModelTrigger, useAssetFont, Icons

// Import statements are harmless (stripped at compile time) but unnecessary:
// import { Chat } from "yumina/Chat";  ← works but not needed

Chat Props

interface ChatProps {
  renderBubble?: (props: BubbleProps) => React.ReactNode;
  className?: string;
  children?: React.ReactNode;
}

BubbleProps

interface BubbleProps {
  contentHtml: string;
  content: string;
  rawContent: string;
  role: "user" | "assistant" | "system";
  messageIndex: number;
  isStreaming: boolean;
  stateSnapshot: Record<string, unknown> | null;
  variables: Record<string, unknown>;
  renderMarkdown: (text: string) => string;
}

SandboxMessage

interface SandboxMessage {
  id: string;
  sessionId: string;
  role: "user" | "assistant" | "system";
  content: string;
  status?: "complete" | "streaming" | "failed";
  errorMessage?: string | null;
  stateChanges?: Record<string, unknown> | null;
  stateSnapshot?: Record<string, unknown> | null;
  swipes?: Array<{ content: string; stateSnapshot?: Record<string, unknown> | null }>;
  activeSwipeIndex?: number;
  model?: string | null;
  tokenCount?: number | null;
  generationTimeMs?: number | null;
  compacted?: boolean;
  attachments?: Array<{ type: string; mimeType: string; name: string; url: string }> | null;
  createdAt: string;
}

SandboxEntry

interface SandboxEntry {
  id: string;
  name: string;
  content: string;
  keywords: string[];
  position: number;
  section: "system-presets" | "examples" | "chat-history" | "post-history";
  enabled: boolean;
  role: string;
  tags?: string[];
}

Global API (Non-React)

window.yumina              // Same API as useYumina()
window.yumina.onChange(cb)  // Subscribe to state changes, returns unsubscribe fn
window.yumina.offChange(cb) // Unsubscribe
// Also dispatches "yumina:statechange" event on window

Sandbox Environment

React is available globally (no import needed). Use React.useState, React.useEffect, etc.

Restrictions

• No fetch / XMLHttpRequest
• No direct localStorage / sessionStorage (use storage.* API instead)
• No window.location manipulation (use navigate())
• No window.parent access
• No eval / new Function
• No cookie access

Compatibility Shims

Old world code without the SDK can still use:

• fetch('/api/*') → proxied through parent with credentials
• localStorage / sessionStorage → world-scoped, proxied to parent
• navigator.clipboard.writeText() → proxied
• window.location → synthetic object

Styling

Tailwind CSS is fully available in the sandbox — use any utility classes (flex, gap-4, text-white, bg-[#1a1a2e], etc.). Inline styles also work:

// Tailwind classes (preferred)
<div className="flex flex-col gap-4 p-4 bg-[#1a1a2e] text-[#e0e0e0] font-serif">

// Inline styles (also fine)
var style = {
  background: "#1a1a2e",
  color: "#e0e0e0",
  fontFamily: '"Noto Serif SC", serif',
  padding: "16px",
};

Multi-File Structure

// index.tsx
import StatusPanel from "./status-panel";
import MapView from "./map-view";

export default function App() {
  return (
    <>
      <StatusPanel />
      <Chat />
      <MapView />
    </>
  );
}