Streaming Agent Widget

Installable vanilla JavaScript widget for embedding a streaming AI assistant on any website.

Installation

npm install @runtypelabs/persona

Building locally

pnpm build

• dist/index.js (ESM), dist/index.cjs (CJS), and dist/index.global.js (IIFE) provide different module formats.
• dist/widget.css is the prefixed Tailwind bundle.
• dist/install.global.js is the automatic installer script for easy script tag installation.

Using with modules

import '@runtypelabs/persona/widget.css';
import {
  initAgentWidget,
  createAgentExperience,
  markdownPostprocessor,
  DEFAULT_WIDGET_CONFIG
} from '@runtypelabs/persona';

const proxyUrl = '/api/chat/dispatch';

// Inline embed
const inlineHost = document.querySelector('#inline-widget')!;
createAgentExperience(inlineHost, {
  ...DEFAULT_WIDGET_CONFIG,
  apiUrl: proxyUrl,
  launcher: { enabled: false },
  theme: {
    ...DEFAULT_WIDGET_CONFIG.theme,
    accent: '#2563eb'
  },
  suggestionChips: ['What can you do?', 'Show API docs'],
  postprocessMessage: ({ text }) => markdownPostprocessor(text)
});

// Floating launcher with runtime updates
const controller = initAgentWidget({
  target: '#launcher-root',
  windowKey: 'chatController', // Optional: stores controller on window.chatController
  config: {
    ...DEFAULT_WIDGET_CONFIG,
    apiUrl: proxyUrl,
    launcher: {
      ...DEFAULT_WIDGET_CONFIG.launcher,
      title: 'AI Assistant',
      subtitle: 'Here to help you get answers fast'
    }
  }
});

// Runtime theme update
document.querySelector('#dark-mode')?.addEventListener('click', () => {
  controller.update({ theme: { surface: '#0f172a', primary: '#f8fafc' } });
});

Initialization options

initAgentWidget accepts the following options:

| Option | Type | Description | | --- | --- | --- | | target | string \| HTMLElement | CSS selector or element where widget mounts. | | config | AgentWidgetConfig | Widget configuration object (see Configuration reference below). | | useShadowDom | boolean | Use Shadow DOM for style isolation (default: true). | | onReady | () => void | Callback fired when widget is initialized. | | windowKey | string | If provided, stores the controller on window[windowKey] for global access. Automatically cleaned up on destroy(). |

Security note: When you return HTML from postprocessMessage, make sure you sanitise it before injecting into the page. The provided postprocessors (markdownPostprocessor, directivePostprocessor) do not perform sanitisation.

Programmatic control

initAgentWidget (and createAgentExperience) return a controller with methods to programmatically control the widget.

Basic controls

const chat = initAgentWidget({
  target: '#launcher-root',
  config: { /* ... */ }
})

document.getElementById('open-chat')?.addEventListener('click', () => chat.open())
document.getElementById('toggle-chat')?.addEventListener('click', () => chat.toggle())
document.getElementById('close-chat')?.addEventListener('click', () => chat.close())

Message hooks

You can programmatically set messages, submit messages, and control voice recognition:

const chat = initAgentWidget({
  target: '#launcher-root',
  config: { /* ... */ }
})

// Set a message in the input field (doesn't submit)
chat.setMessage("Hello, I need help")

// Submit a message (uses textarea value if no argument provided)
chat.submitMessage()
// Or submit a specific message
chat.submitMessage("What are your hours?")

// Start voice recognition
chat.startVoiceRecognition()

// Stop voice recognition
chat.stopVoiceRecognition()

All hook methods return boolean indicating success (true) or failure (false). They will automatically open the widget if it's currently closed (when launcher is enabled).

Clear chat

const chat = initAgentWidget({
  target: '#launcher-root',
  config: { /* ... */ }
})

// Clear all messages programmatically
chat.clearChat()

Message Injection

Inject messages programmatically from external sources like tool call responses, system events, or third-party integrations. This is useful when local tools need to push results back into the conversation.

const chat = initAgentWidget({
  target: '#launcher-root',
  config: { /* ... */ }
})

// Simple message injection
chat.injectAssistantMessage({
  content: 'Here are your search results...'
});

// User message injection
chat.injectUserMessage({
  content: 'Add to cart'
});

// System context injection
chat.injectSystemMessage({
  content: '[Context updated]',
  llmContent: 'User is viewing product page for iPhone 15 Pro'
});

Dual-Content Messages (llmContent)

Use llmContent to show different content to the user versus what gets sent to the LLM. This is useful for:

• Token efficiency: Show rich content to users while sending concise summaries to the LLM
• Sensitive data redaction: Display PII to users while hiding it from the LLM
• Context injection: Provide detailed LLM context with minimal UI footprint

// Example: Tool callback that injects search results
async function handleProductSearch(query: string) {
  const results = await searchProducts(query);

  // User sees full product details with images and prices
  // LLM receives a concise summary to save tokens
  chat.injectAssistantMessage({
    content: `**Found ${results.length} products:**
${results.map(p => `- ${p.name} - $${p.price} (SKU: ${p.sku})`).join('\n')}`,

    llmContent: `[Search results: ${results.length} products found, price range $${results.minPrice}-$${results.maxPrice}]`
  });
}

// Example: Redacting sensitive information
chat.injectAssistantMessage({
  // User sees their order confirmation with details
  content: `Your order #12345 has been placed!
- Card ending in 4242
- Shipping to: 123 Main St, Anytown, USA`,

  // LLM only knows an order was placed (no PII)
  llmContent: '[Order confirmation displayed to user]'
});

Content Priority

When messages are sent to the API, content is resolved in this priority order:

1. contentParts - Multi-modal content (images, files)
2. llmContent - Explicit LLM-specific content
3. content - Display content as fallback

Streaming Updates

For long-running operations, use the same message ID to update content:

const messageId = 'search-123';

// Show loading state
chat.injectAssistantMessage({
  id: messageId,
  content: 'Searching...',
  streaming: true
});

// Update with results
chat.injectAssistantMessage({
  id: messageId,
  content: 'Found 5 results...',
  llmContent: '[5 search results]',
  streaming: false
});

Accessing from window

To access the controller globally (e.g., from browser console or external scripts), use the windowKey option:

const chat = initAgentWidget({
  target: '#launcher-root',
  windowKey: 'chatController', // Stores controller on window.chatController
  config: { /* ... */ }
})

// Now accessible globally
window.chatController.setMessage("Hello from console!")
window.chatController.submitMessage("Test message")
window.chatController.startVoiceRecognition()

Message Types

The widget uses AgentWidgetMessage objects to represent messages in the conversation. You can access these through postprocessMessage callbacks or by inspecting the session's message array.

type AgentWidgetMessage = {
  id: string;                    // Unique message identifier
  role: "user" | "assistant" | "system";
  content: string;               // Message text content
  createdAt: string;             // ISO timestamp
  streaming?: boolean;           // Whether message is still streaming
  variant?: "assistant" | "reasoning" | "tool";
  sequence?: number;             // Message ordering
  reasoning?: AgentWidgetReasoning;
  toolCall?: AgentWidgetToolCall;
  tools?: AgentWidgetToolCall[];
  viaVoice?: boolean;            // Indicates if user message was sent via voice input
};

viaVoice field: Set to true when a user message is sent through voice recognition. This allows you to implement voice-specific behaviors, such as automatically reactivating voice recognition after assistant responses. You can check this field in your postprocessMessage callback:

postprocessMessage: ({ message, text, streaming }) => {
  if (message.role === 'user' && message.viaVoice) {
    console.log('User sent message via voice');
  }
  return text;
}

Alternatively, manually assign the controller:

const chat = initAgentWidget({ /* ... */ })
window.chatController = chat

DOM Events

The widget dispatches custom DOM events that you can listen to for integration with your application:

persona:clear-chat

Dispatched when the user clicks the "Clear chat" button or when chat.clearChat() is called programmatically.

window.addEventListener("persona:clear-chat", (event) => {
  console.log("Chat cleared at:", event.detail.timestamp);
  // Clear your localStorage, reset state, etc.
});

Event detail:

• timestamp: ISO timestamp string of when the chat was cleared

Use cases:

• Clear localStorage chat history
• Reset application state
• Track analytics events
• Sync with backend

Note: The widget automatically clears the "persona-chat-history" localStorage key by default when chat is cleared. If you set clearChatHistoryStorageKey in the config, it will also clear that additional key. You can still listen to this event for additional custom behavior.

Controller Events

The widget controller exposes an event system for reacting to chat events. Use controller.on(eventName, callback) to subscribe and controller.off(eventName, callback) to unsubscribe.

Available Events

| Event | Payload | Description | |-------|---------|-------------| | user:message | AgentWidgetMessage | Emitted when a new user message is detected. Includes viaVoice: true if sent via voice. | | assistant:message | AgentWidgetMessage | Emitted when an assistant message starts streaming | | assistant:complete | AgentWidgetMessage | Emitted when an assistant message finishes streaming | | voice:state | AgentWidgetVoiceStateEvent | Emitted when voice recognition state changes | | action:detected | AgentWidgetActionEventPayload | Emitted when an action is parsed from an assistant message | | widget:opened | AgentWidgetStateEvent | Emitted when the widget panel opens | | widget:closed | AgentWidgetStateEvent | Emitted when the widget panel closes | | widget:state | AgentWidgetStateSnapshot | Emitted on any widget state change | | message:feedback | AgentWidgetMessageFeedback | Emitted when user provides feedback (upvote/downvote) | | message:copy | AgentWidgetMessage | Emitted when user copies a message |

Event Payload Types

// Voice state event
type AgentWidgetVoiceStateEvent = {
  active: boolean;
  source: "user" | "auto" | "restore" | "system";
  timestamp: number;
};

// Widget state event (for opened/closed)
type AgentWidgetStateEvent = {
  open: boolean;
  source: "user" | "auto" | "api" | "system";
  timestamp: number;
};

// Widget state snapshot
type AgentWidgetStateSnapshot = {
  open: boolean;
  launcherEnabled: boolean;
  voiceActive: boolean;
  streaming: boolean;
};

// Action event payload
type AgentWidgetActionEventPayload = {
  action: AgentWidgetParsedAction;
  message: AgentWidgetMessage;
};

// Message feedback
type AgentWidgetMessageFeedback = {
  type: "upvote" | "downvote";
  messageId: string;
  message: AgentWidgetMessage;
};

Example: Listening to Events

const chat = initAgentWidget({
  target: 'body',
  config: { apiUrl: '/api/chat/dispatch' }
});

// Listen for new user messages
chat.on('user:message', (message) => {
  console.log('User sent:', message.content);
  if (message.viaVoice) {
    console.log('Message was sent via voice recognition');
  }
});

// Listen for completed assistant responses
chat.on('assistant:complete', (message) => {
  console.log('Assistant replied:', message.content);
});

// Listen for voice state changes
chat.on('voice:state', (event) => {
  console.log('Voice active:', event.active, 'Source:', event.source);
});

// Listen for widget open/close
chat.on('widget:opened', (event) => {
  console.log('Widget opened by:', event.source);
});

chat.on('widget:closed', (event) => {
  console.log('Widget closed by:', event.source);
});

// Listen for parsed actions from assistant messages
chat.on('action:detected', ({ action, message }) => {
  console.log('Action detected:', action.type, action.payload);
});

Example: Voice Mode Persistence

The user:message event is useful for implementing custom voice mode persistence across page navigations:

const chat = initAgentWidget({
  target: 'body',
  config: {
    apiUrl: '/api/chat/dispatch',
    voiceRecognition: { enabled: true }
  }
});

// Track if the user is in "voice mode"
chat.on('user:message', (message) => {
  localStorage.setItem('voice-mode', message.viaVoice ? 'true' : 'false');
});

// On page load, restore voice mode if the user was using voice
if (localStorage.getItem('voice-mode') === 'true') {
  chat.startVoiceRecognition();
}

Note: The built-in persistState option handles this automatically when configured:

initAgentWidget({
  target: 'body',
  config: {
    persistState: true,  // Automatically persists open state and voice mode
    voiceRecognition: { enabled: true, autoResume: 'assistant' }
  }
});

State Loaded Hook

The onStateLoaded hook is called after state is loaded from the storage adapter, but before the widget initializes. Use this to transform or inject messages based on external state (e.g., navigation flags, checkout returns).

initAgentWidget({
  target: 'body',
  config: {
    storageAdapter: createLocalStorageAdapter('my-chat'),
    onStateLoaded: (state) => {
      // Check for pending navigation message
      const navMessage = consumeNavigationFlag();
      if (navMessage) {
        return {
          ...state,
          messages: [...(state.messages || []), {
            id: `nav-${Date.now()}`,
            role: 'assistant',
            content: navMessage,
            createdAt: new Date().toISOString()
          }]
        };
      }
      return state;
    }
  }
});

Use cases:

• Inject messages after page navigation (e.g., "Here are our products!")
• Add confirmation messages after checkout/payment returns
• Transform or filter loaded messages
• Inject system messages based on external state

The hook receives the loaded state and must return the (potentially modified) state synchronously.

Message Actions (Copy, Upvote, Downvote)

The widget includes built-in action buttons for assistant messages that allow users to copy message content and provide feedback through upvote/downvote buttons.

Configuration

const controller = initAgentWidget({
  target: '#app',
  config: {
    apiUrl: '/api/chat/dispatch',
    
    // Message actions configuration
    messageActions: {
      enabled: true,              // Enable/disable all action buttons (default: true)
      showCopy: true,             // Show copy button (default: true)
      showUpvote: true,           // Show upvote button (default: false - requires backend)
      showDownvote: true,         // Show downvote button (default: false - requires backend)
      visibility: 'hover',        // 'hover' or 'always' (default: 'hover')
      align: 'right',             // 'left', 'center', or 'right' (default: 'right')
      layout: 'pill-inside',      // 'pill-inside' (compact floating) or 'row-inside' (full-width bar)
      
      // Optional callbacks (called in addition to events)
      onCopy: (message) => {
        console.log('Copied:', message.id);
      },
      onFeedback: (feedback) => {
        console.log('Feedback:', feedback.type, feedback.messageId);
        // Send to your analytics/backend
        fetch('/api/feedback', {
          method: 'POST',
          headers: { 'Content-Type': 'application/json' },
          body: JSON.stringify(feedback)
        });
      }
    }
  }
});

Feedback Events

Listen to feedback events via the controller:

// Copy event - fired when user copies a message
controller.on('message:copy', (message) => {
  console.log('Message copied:', message.id, message.content);
});

// Feedback event - fired when user upvotes or downvotes
controller.on('message:feedback', (feedback) => {
  console.log('Feedback received:', {
    type: feedback.type,         // 'upvote' or 'downvote'
    messageId: feedback.messageId,
    message: feedback.message    // Full message object
  });
});

Feedback Types

type AgentWidgetMessageFeedback = {
  type: 'upvote' | 'downvote';
  messageId: string;
  message: AgentWidgetMessage;
};

type AgentWidgetMessageActionsConfig = {
  enabled?: boolean;
  showCopy?: boolean;
  showUpvote?: boolean;
  showDownvote?: boolean;
  visibility?: 'always' | 'hover';
  onFeedback?: (feedback: AgentWidgetMessageFeedback) => void;
  onCopy?: (message: AgentWidgetMessage) => void;
};

Visual Behavior

• Hover mode (visibility: 'hover'): Action buttons appear when hovering over assistant messages
• Always mode (visibility: 'always'): Action buttons are always visible
• Copy button: Shows a checkmark briefly after successful copy
• Vote buttons: Toggle active state and are mutually exclusive (upvoting clears downvote and vice versa)

Runtype adapter

This package ships with a Runtype adapter by default. The proxy handles all flow configuration, keeping the client lightweight and flexible.

Flow configuration happens server-side - you have three options:

1. Use default flow - The proxy includes a basic streaming chat flow out of the box
2. Reference a Runtype flow ID - Configure flows in your Runtype dashboard and reference them by ID
3. Define custom flows - Build flow configurations directly in the proxy

The client simply sends messages to the proxy, which constructs the full Runtype payload. This architecture allows you to:

• Change models/prompts without redeploying the widget
• A/B test different flows server-side
• Enforce security and cost controls centrally
• Support multiple flows for different use cases

Dynamic Forms (Recommended)

For rendering AI-generated forms, use the component middleware approach with the DynamicForm component. This allows the AI to create contextually appropriate forms with any fields:

import { componentRegistry, initAgentWidget } from "@runtypelabs/persona";
import { DynamicForm } from "./components"; // Your DynamicForm component

// Register the component
componentRegistry.register("DynamicForm", DynamicForm);

initAgentWidget({
  target: "#app",
  config: {
    apiUrl: "/api/chat/dispatch-directive",
    parserType: "json",
    enableComponentStreaming: true,
    formEndpoint: "/form",
    // Optional: customize form appearance
    formStyles: {
      borderRadius: "16px",
      borderWidth: "1px",
      borderColor: "#e5e7eb",
      padding: "1.5rem",
      titleFontSize: "1.25rem",
      buttonBorderRadius: "9999px"
    }
  }
});

The AI responds with JSON like:

{
  "text": "Please fill out this form:",
  "component": "DynamicForm",
  "props": {
    "title": "Contact Us",
    "fields": [
      { "label": "Name", "type": "text", "required": true },
      { "label": "Email", "type": "email", "required": true }
    ],
    "submit_text": "Submit"
  }
}

See examples/embedded-app/json.html for a full working example.

Directive postprocessor (Deprecated)

⚠️ Deprecated: The directivePostprocessor approach is deprecated in favor of the component middleware with DynamicForm. The old approach only supports predefined form templates ("init" and "followup"), while the new approach allows AI-generated forms with any fields.

directivePostprocessor looks for either <Form type="init" /> tokens or <Directive>{"component":"form","type":"init"}</Directive> blocks and swaps them for placeholders that the widget upgrades into interactive UI. This approach is limited to the predefined form templates in formDefinitions.

Script tag installation

The widget can be installed via a simple script tag, perfect for platforms where you can't compile custom code. There are two methods:

Method 1: Automatic installer (recommended)

The easiest way is to use the automatic installer script. It handles loading CSS and JavaScript, then initializes the widget automatically:

<!-- Add this before the closing </body> tag -->
<script>
  window.siteAgentConfig = {
    target: 'body', // or '#my-container' for specific placement
    config: {
      apiUrl: 'https://your-proxy.com/api/chat/dispatch',
      launcher: {
        enabled: true,
        title: 'AI Assistant',
        subtitle: 'How can I help you?'
      },
      theme: {
        accent: '#2563eb',
        surface: '#ffffff'
      },
      // Optional: configure stream parser for JSON/XML responses
      // streamParser: () => window.AgentWidget.createJsonStreamParser()
    }
  };
</script>
<script src="https://cdn.jsdelivr.net/npm/@runtypelabs/persona@latest/dist/install.global.js"></script>

Installer options:

• version - Package version to load (default: "latest")
• cdn - CDN provider: "jsdelivr" or "unpkg" (default: "jsdelivr")
• cssUrl - Custom CSS URL (overrides CDN)
• jsUrl - Custom JS URL (overrides CDN)
• target - CSS selector or element where widget mounts (default: "body")
• config - Widget configuration object (see Configuration reference)
• autoInit - Automatically initialize after loading (default: true)

Example with version pinning:

<script>
  window.siteAgentConfig = {
    version: '0.1.0', // Pin to specific version
    config: {
      apiUrl: '/api/chat/dispatch',
      launcher: { enabled: true, title: 'Support Chat' }
    }
  };
</script>
<script src="https://cdn.jsdelivr.net/npm/@runtypelabs/[email protected]/dist/install.global.js"></script>

Method 2: Manual installation

For more control, manually load CSS and JavaScript:

<!-- Load CSS -->
<link rel="stylesheet" href="https://cdn.jsdelivr.net/npm/@runtypelabs/persona@latest/dist/widget.css" />

<!-- Load JavaScript -->
<script src="https://cdn.jsdelivr.net/npm/@runtypelabs/persona@latest/dist/index.global.js"></script>

<!-- Initialize widget -->
<script>
  const chatController = window.AgentWidget.initAgentWidget({
    target: '#persona-anchor', // or 'body' for floating launcher
    windowKey: 'chatWidget', // Optional: stores controller on window.chatWidget
    config: {
      apiUrl: '/api/chat/dispatch',
      launcher: {
        enabled: true,
        title: 'AI Assistant',
        subtitle: 'Here to help'
      },
      theme: {
        accent: '#111827',
        surface: '#f5f5f5'
      },
      // Optional: configure stream parser for JSON/XML responses
      streamParser: window.AgentWidget.createJsonStreamParser // or createXmlParser, createPlainTextParser
    }
  });
  
  // Controller is now available as window.chatWidget (if windowKey was used)
  // or use the returned chatController variable
</script>

CDN options:

• jsDelivr (recommended): https://cdn.jsdelivr.net/npm/@runtypelabs/persona@VERSION/dist/
• unpkg: https://unpkg.com/@runtypelabs/persona@VERSION/dist/

Replace VERSION with latest for auto-updates, or a specific version like 0.1.0 for stability.

Available files:

• widget.css - Stylesheet (required)
• index.global.js - Widget JavaScript (IIFE format)
• install.global.js - Automatic installer script

The script build exposes a window.AgentWidget global with initAgentWidget() and other exports, including parser functions:

• window.AgentWidget.initAgentWidget() - Initialize the widget
• window.AgentWidget.createPlainTextParser() - Plain text parser (default)
• window.AgentWidget.createJsonStreamParser() - JSON parser using schema-stream
• window.AgentWidget.createXmlParser() - XML parser
• window.AgentWidget.markdownPostprocessor() - Markdown postprocessor
• window.AgentWidget.directivePostprocessor() - Directive postprocessor (deprecated)
• window.AgentWidget.componentRegistry - Component registry for custom components

React Framework Integration

The widget is fully compatible with React frameworks. Use the ESM imports to integrate it as a client component.

Framework Compatibility

| Framework | Compatible | Implementation Notes | |-----------|------------|---------------------| | Vite | ✅ Yes | No special requirements - works out of the box | | Create React App | ✅ Yes | No special requirements - works out of the box | | Next.js | ✅ Yes | Requires 'use client' directive (App Router) | | Remix | ✅ Yes | Use dynamic import or useEffect guard for SSR | | Gatsby | ✅ Yes | Use in wrapRootElement or check typeof window !== 'undefined' | | Astro | ✅ Yes | Use client:load or client:only="react" directive |

Quick Start with Vite or Create React App

For client-side-only React frameworks (Vite, CRA), create a component:

// src/components/ChatWidget.tsx
import { useEffect } from 'react';
import '@runtypelabs/persona/widget.css';
import { initAgentWidget, markdownPostprocessor } from '@runtypelabs/persona';
import type { AgentWidgetInitHandle } from '@runtypelabs/persona';

export function ChatWidget() {
  useEffect(() => {
    let handle: AgentWidgetInitHandle | null = null;
    
    handle = initAgentWidget({
      target: 'body',
      config: {
        apiUrl: "/api/chat/dispatch",
        theme: {
          primary: "#111827",
          accent: "#1d4ed8",
        },
        launcher: {
          enabled: true,
          title: "Chat Assistant",
          subtitle: "Here to help you get answers fast"
        },
        postprocessMessage: ({ text }) => markdownPostprocessor(text)
      }
    });

    // Cleanup on unmount
    return () => {
      if (handle) {
        handle.destroy();
      }
    };
  }, []);

  return null; // Widget injects itself into the DOM
}

Then use it in your app:

// src/App.tsx
import { ChatWidget } from './components/ChatWidget';

function App() {
  return (
    <div>
      {/* Your app content */}
      <ChatWidget />
    </div>
  );
}

export default App;

Next.js Integration

For Next.js App Router, add the 'use client' directive:

// components/ChatWidget.tsx
'use client';

import { useEffect } from 'react';
import '@runtypelabs/persona/widget.css';
import { initAgentWidget, markdownPostprocessor } from '@runtypelabs/persona';
import type { AgentWidgetInitHandle } from '@runtypelabs/persona';

export function ChatWidget() {
  useEffect(() => {
    let handle: AgentWidgetInitHandle | null = null;
    
    handle = initAgentWidget({
      target: 'body',
      config: {
        apiUrl: "/api/chat/dispatch",
        launcher: {
          enabled: true,
          title: "Chat Assistant",
        },
        postprocessMessage: ({ text }) => markdownPostprocessor(text)
      }
    });

    return () => {
      if (handle) {
        handle.destroy();
      }
    };
  }, []);

  return null;
}

Use it in your layout or page:

// app/layout.tsx
import { ChatWidget } from '@/components/ChatWidget';

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body>
        {children}
        <ChatWidget />
      </body>
    </html>
  );
}

Alternative: Dynamic Import (SSR-Safe)

If you encounter SSR issues, use Next.js dynamic imports:

// app/layout.tsx
import dynamic from 'next/dynamic';

const ChatWidget = dynamic(
  () => import('@/components/ChatWidget').then(mod => mod.ChatWidget),
  { ssr: false }
);

export default function RootLayout({ children }) {
  return (
    <html lang="en">
      <body>
        {children}
        <ChatWidget />
      </body>
    </html>
  );
}

Remix Integration

For Remix, guard the widget initialization with a client-side check:

// app/components/ChatWidget.tsx
import { useEffect, useState } from 'react';

export function ChatWidget() {
  const [mounted, setMounted] = useState(false);

  useEffect(() => {
    setMounted(true);
    
    // Dynamic import to avoid SSR issues
    import('@runtypelabs/persona/widget.css');
    import('@runtypelabs/persona').then(({ initAgentWidget, markdownPostprocessor }) => {
      const handle = initAgentWidget({
        target: 'body',
        config: {
          apiUrl: "/api/chat/dispatch",
          launcher: { enabled: true },
          postprocessMessage: ({ text }) => markdownPostprocessor(text)
        }
      });
      
      return () => handle?.destroy();
    });
  }, []);

  if (!mounted) return null;
  return null;
}

Gatsby Integration

Use Gatsby's wrapRootElement API:

// gatsby-browser.js
import { ChatWidget } from './src/components/ChatWidget';

export const wrapRootElement = ({ element }) => (
  <>
    {element}
    <ChatWidget />
  </>
);

Astro Integration

Use Astro's client directives with React islands:

---
// src/components/ChatWidget.astro
import { ChatWidget } from './ChatWidget.tsx';
---

<ChatWidget client:load />

Using the Theme Configurator

For easy configuration generation, use the Theme Configurator which includes a "React (Client Component)" export option. It generates a complete React component with your custom theme, launcher settings, and all configuration options.

Installation

npm install @runtypelabs/persona
# or
pnpm add @runtypelabs/persona
# or
yarn add @runtypelabs/persona

Key Considerations

1. CSS Import: The CSS import (import '@runtypelabs/persona/widget.css') works natively with all modern React build tools
2. Client-Side Only: The widget manipulates the DOM, so it must run client-side only
3. Cleanup: Always call handle.destroy() in the cleanup function to prevent memory leaks
4. API Routes: Ensure your apiUrl points to a valid backend endpoint
5. TypeScript Support: Full TypeScript definitions are included for all exports

Using default configuration

The package exports a complete default configuration that you can use as a base:

import { DEFAULT_WIDGET_CONFIG, mergeWithDefaults } from '@runtypelabs/persona';

// Option 1: Use defaults with selective overrides
const controller = initAgentWidget({
  target: '#app',
  config: {
    ...DEFAULT_WIDGET_CONFIG,
    apiUrl: '/api/chat/dispatch',
    theme: {
      ...DEFAULT_WIDGET_CONFIG.theme,
      accent: '#custom-color'  // Override only what you need
    }
  }
});

// Option 2: Use the merge helper
const controller = initAgentWidget({
  target: '#app',
  config: mergeWithDefaults({
    apiUrl: '/api/chat/dispatch',
    theme: { accent: '#custom-color' }
  })
});

This ensures all configuration values are set to sensible defaults while allowing you to customize only what you need.

Configuration reference

| Option | Type | Description | | --- | --- | --- | | apiUrl | string | Proxy endpoint for your chat backend (defaults to Runtype's cloud API). | | flowId | string | Optional Runtype flow ID. If provided, the client sends it to the proxy which can use it to select a specific flow. | | headers | Record<string, string> | Extra headers forwarded to your proxy. | | copy | { welcomeTitle?, welcomeSubtitle?, inputPlaceholder?, sendButtonLabel? } | Customize user-facing text. | | theme | { primary?, secondary?, surface?, muted?, accent?, radiusSm?, radiusMd?, radiusLg?, radiusFull? } | Override CSS variables for the widget. Colors: primary (text/UI), secondary (unused), surface (backgrounds), muted (secondary text), accent (buttons/links). Border radius: radiusSm (0.75rem, inputs), radiusMd (1rem, cards), radiusLg (1.5rem, panels/bubbles), radiusFull (9999px, pills/buttons). | | features | AgentWidgetFeatureFlags | Toggle UI features: showReasoning? (show thinking bubbles, default: true), showToolCalls? (show tool usage bubbles, default: true). | | launcher | { enabled?, autoExpand?, title?, subtitle?, iconUrl?, position? } | Controls the floating launcher button. | | initialMessages | AgentWidgetMessage[] | Seed the conversation transcript. | | suggestionChips | string[] | Render quick reply buttons above the composer. | | postprocessMessage | (ctx) => string | Transform message text before it renders (return HTML). Combine with markdownPostprocessor for rich output. | | parserType | "plain" \| "json" \| "regex-json" \| "xml" | Built-in parser type selector. Easy way to choose a parser without importing functions. Options: "plain" (default), "json" (partial-json), "regex-json" (regex-based), "xml". If both parserType and streamParser are provided, streamParser takes precedence. | | streamParser | () => AgentWidgetStreamParser | Custom stream parser for detecting formats and extracting text from streaming responses. Handles JSON, XML, or custom formats. See Stream Parser Configuration below. | | clearChatHistoryStorageKey | string | Additional localStorage key to clear when the clear chat button is clicked. The widget automatically clears "persona-chat-history" by default. Use this option to clear additional keys (e.g., if you're using a custom storage key). | | formEndpoint | string | Endpoint used by built-in directives (defaults to /form). | | launcherWidth | string | CSS width applied to the floating launcher panel (e.g. 320px, 90vw). Defaults to min(400px, calc(100vw - 24px)). | | debug | boolean | Emits verbose logs to console. |

All options are safe to mutate via initAgentWidget(...).update(newConfig).

Stream Parser Configuration

The widget can parse structured responses (JSON, XML, etc.) that stream in chunk by chunk, extracting the text field for display. By default, it uses a plain text parser. You can easily select a built-in parser using parserType, or provide a custom parser via streamParser.

Key benefits of the unified stream parser:

• Format detection: Automatically detects if content matches your parser's format
• Extensible: Handle JSON, XML, or any custom structured format
• Incremental parsing: Extract text as it streams in, not just when complete

Quick start with parserType (recommended):

The easiest way to use a built-in parser is with the parserType option:

import { initAgentWidget } from '@runtypelabs/persona';

const controller = initAgentWidget({
  target: '#chat-root',
  config: {
    apiUrl: '/api/chat/dispatch',
    parserType: 'json'  // Options: 'plain', 'json', 'regex-json', 'xml'
  }
});

Using built-in parsers with streamParser (ESM/Modules):

import { initAgentWidget, createPlainTextParser, createJsonStreamParser, createXmlParser } from '@runtypelabs/persona';

const controller = initAgentWidget({
  target: '#chat-root',
  config: {
    apiUrl: '/api/chat/dispatch',
    streamParser: createJsonStreamParser // Use JSON parser
    // Or: createXmlParser for XML, createPlainTextParser for plain text (default)
  }
});

Using built-in parsers with CDN Script Tags:

<script src="https://cdn.jsdelivr.net/npm/@runtypelabs/persona@latest/dist/index.global.js"></script>
<script>
  window.AgentWidget.initAgentWidget({
    target: '#chat-root',
    config: {
      apiUrl: '/api/chat/dispatch',
      streamParser: window.AgentWidget.createJsonStreamParser // JSON parser
      // Or: window.AgentWidget.createXmlParser for XML
      // Or: window.AgentWidget.createPlainTextParser for plain text (default)
    }
  });
</script>

Using with automatic installer script:

<script>
  window.siteAgentConfig = {
    target: 'body',
    config: {
      apiUrl: '/api/chat/dispatch',
      parserType: 'json'  // Simple way to select parser - no function imports needed!
    }
  };
</script>
<script src="https://cdn.jsdelivr.net/npm/@runtypelabs/persona@latest/dist/install.global.js"></script>

Alternative: Using streamParser with installer script:

If you need a custom parser, you can still use streamParser:

<script>
  window.siteAgentConfig = {
    target: 'body',
    config: {
      apiUrl: '/api/chat/dispatch',
      // Note: streamParser must be set after the script loads, or use a function
      streamParser: function() {
        return window.AgentWidget.createJsonStreamParser();
      }
    }
  };
</script>
<script src="https://cdn.jsdelivr.net/npm/@runtypelabs/persona@latest/dist/install.global.js"></script>

Alternatively, you can set it after the script loads:

<script>
  window.siteAgentConfig = {
    target: 'body',
    config: {
      apiUrl: '/api/chat/dispatch'
    }
  };
</script>
<script src="https://cdn.jsdelivr.net/npm/@runtypelabs/persona@latest/dist/install.global.js"></script>
<script>
  // Set parser after AgentWidget is loaded
  if (window.siteAgentConfig && window.AgentWidget) {
    window.siteAgentConfig.config.streamParser = window.AgentWidget.createJsonStreamParser;
  }
</script>

Custom JSON parser example:

const jsonParser = () => {
  let extractedText = null;
  
  return {
    // Extract text field from JSON as it streams in
    // Return null if not JSON or text not available yet
    processChunk(accumulatedContent) {
      const trimmed = accumulatedContent.trim();
      // Return null if not JSON format
      if (!trimmed.startsWith('{') && !trimmed.startsWith('[')) {
        return null;
      }
      
      const match = accumulatedContent.match(/"text"\s*:\s*"([^"]*(?:\\.[^"]*)*)"/);
      if (match) {
        extractedText = match[1].replace(/\\"/g, '"').replace(/\\n/g, '\n');
        return extractedText;
      }
      return null;
    },
    
    getExtractedText() {
      return extractedText;
    }
  };
};

initAgentWidget({
  target: '#chat-root',
  config: {
    apiUrl: '/api/chat/dispatch',
    streamParser: jsonParser,
    postprocessMessage: ({ text, raw }) => {
      // raw contains the structured payload (JSON, XML, etc.)
      return markdownPostprocessor(text);
    }
  }
});

Custom XML parser example:

const xmlParser = () => {
  let extractedText = null;
  
  return {
    processChunk(accumulatedContent) {
      // Return null if not XML format
      if (!accumulatedContent.trim().startsWith('<')) {
        return null;
      }
      
      // Extract text from <text>...</text> tags
      const match = accumulatedContent.match(/<text[^>]*>([\s\S]*?)<\/text>/);
      if (match) {
        extractedText = match[1];
        return extractedText;
      }
      return null;
    },
    
    getExtractedText() {
      return extractedText;
    }
  };
};

Parser interface:

interface AgentWidgetStreamParser {
  // Process a chunk and return extracted text (if available)
  // Return null if the content doesn't match this parser's format or text is not yet available
  processChunk(accumulatedContent: string): Promise<string | null> | string | null;
  
  // Get the currently extracted text (may be partial)
  getExtractedText(): string | null;
  
  // Optional cleanup when parsing is complete
  close?(): Promise<void> | void;
}

The parser's processChunk method is called for each chunk. If the content matches your parser's format, return the extracted text and the raw payload. Built-in parsers already do this, so action handlers and middleware can read the original structured content without re-implementing a parser. Return null if the chunk isn't ready yet—the widget will keep waiting or fall back to plain text.

Optional proxy server

The proxy server handles flow configuration and forwards requests to Runtype. You can configure it in three ways:

Option 1: Use default flow (recommended for getting started)

// api/chat.ts
import { createChatProxyApp } from '@runtypelabs/persona-proxy';

export default createChatProxyApp({
  path: '/api/chat/dispatch',
  allowedOrigins: ['https://www.example.com']
});

Option 2: Reference a Runtype flow ID

import { createChatProxyApp } from '@runtypelabs/persona-proxy';

export default createChatProxyApp({
  path: '/api/chat/dispatch',
  allowedOrigins: ['https://www.example.com'],
  flowId: 'flow_abc123' // Flow created in Runtype dashboard or API
});

Option 3: Define a custom flow

import { createChatProxyApp } from '@runtypelabs/persona-proxy';

export default createChatProxyApp({
  path: '/api/chat/dispatch',
  allowedOrigins: ['https://www.example.com'],
  flowConfig: {
    name: "Custom Chat Flow",
    description: "Specialized assistant flow",
    steps: [
      {
        id: "custom_prompt",
        name: "Custom Prompt",
        type: "prompt",
        enabled: true,
        config: {
          model: "meta/llama3.1-8b-instruct-free",
          responseFormat: "markdown",
          outputVariable: "prompt_result",
          userPrompt: "{{user_message}}",
          systemPrompt: "you are a helpful assistant, chatting with a user",
          previousMessages: "{{messages}}"
        }
      }
    ]
  }
});

Hosting on Vercel:

import { createVercelHandler } from '@runtypelabs/persona-proxy';

export default createVercelHandler({
  allowedOrigins: ['https://www.example.com'],
  flowId: 'flow_abc123' // Optional
});

Environment setup:

Add RUNTYPE_API_KEY to your environment. The proxy constructs the Runtype payload (including flow configuration) and streams the response back to the client.

Development notes

• The widget streams results using SSE and mirrors the backend flow_complete/step_chunk events.
• Tailwind-esc classes are prefixed with tvw- and scoped to #persona-root, so they won't collide with the host page.
• Run pnpm dev from the repository root to boot the example proxy (examples/proxy) and the vanilla demo (examples/embedded-app).
• The proxy prefers port 43111 but automatically selects the next free port if needed.