Events

The SDK uses a type-safe event system for all communication. Events are the primary way to react to agent responses, connection state changes, and errors.

Event Structure

All events follow a consistent structure:

interface AgentEvent<T> {
  type: string;           // Event type identifier
  timestamp: number;      // Unix timestamp (ms)
  sessionId?: string;     // Current session ID
  agentId?: string;       // Agent ID
  payload: T;             // Event-specific data
}

Connection Events

connected

Emitted when WebSocket connection is established.

agent.on("connected", (event) => {
  console.log("Connected!", {
    sessionId: event.sessionId,
    agentId: event.agentId,
    timestamp: new Date(event.timestamp)
  });
});

closed

Emitted when connection is closed.

agent.on("closed", (event) => {
  const { code, reason } = event.payload;
  console.log(`Connection closed: ${code} - ${reason}`);
});

Payload:

Property	Type	Description
code	number?	WebSocket close code
reason	string?	Close reason

stateChanged

Emitted on any connection state transition.

agent.on("stateChanged", (event) => {
  const { state, previousState } = event.payload;
  console.log(`State: ${previousState} → ${state}`);
  
  switch (state) {
    case "CONNECTING":
      showConnectingIndicator();
      break;
    case "CONNECTED":
      hideConnectingIndicator();
      break;
    case "RECONNECTING":
      showReconnectingBanner();
      break;
    case "CLOSED":
      showDisconnectedMessage();
      break;
  }
});

Connection States:

State	Description
IDLE	Initial state, not connected
CONNECTING	Establishing connection
CONNECTED	Successfully connected
RECONNECTING	Attempting reconnection
CLOSED	Connection closed

Message Events

message

Emitted for every incoming message (raw).

agent.on("message", (event) => {
  console.log("Raw message:", event.payload.data);
});

agentMessage

Emitted when an agent response is received (parsed and typed).

agent.on("agentMessage", (event) => {
  const { message, from, to, attachments } = event.payload;
  
  console.log("Agent says:", message?.content);
  console.log("From:", from?.name);
  
  if (attachments?.length) {
    console.log("Attachments:", attachments);
  }
});

Payload:

Property	Type	Description
message	Message	The message object
type	string	Message type identifier
from	object?	Sender information
to	object?	Recipient information
attachments	array?	File attachments

errorMessage

Emitted when an error message is received from the agent.

agent.on("errorMessage", (event) => {
  const { message, error } = event.payload;
  
  console.error("Error from agent:", error.message);
  console.error("Original message:", message);
  
  // Optionally show user-friendly error
  showErrorToUser("Something went wrong. Please try again.");
});

heartbeat

Emitted when the agent is processing (typing indicator).

agent.on("heartbeat", (event) => {
  showTypingIndicator();
  
  // Auto-hide after timeout
  setTimeout(() => {
    hideTypingIndicator();
  }, 3000);
});

System Events

error

Emitted on SDK errors (connection, auth, message processing).

import { ConnectionError, AuthError, MessageError } from "@egain/ai-agent-sdk";

agent.on("error", (event) => {
  const error = event.payload.error;
  
  if (error instanceof ConnectionError) {
    console.error("Connection error:", error.message);
    // Maybe retry or show offline UI
  } else if (error instanceof AuthError) {
    console.error("Auth error:", error.message);
    // Redirect to login
  } else if (error instanceof MessageError) {
    console.error("Message error:", error.message);
    // Show message failed UI
  }
});

queueFlushed

Emitted when queued messages are sent after reconnection.

agent.on("queueFlushed", (event) => {
  console.log(`Sent ${event.payload.count} queued messages`);
  showNotification("Your messages have been sent!");
});

tokenExpiring

Emitted when authentication token is about to expire.

agent.on("tokenExpiring", async (event) => {
  const { reason, expiresAt } = event.payload;
  
  if (reason === "expiring") {
    console.log(`Token expires at: ${new Date(expiresAt!)}`);
  }
  
  // Refresh the token
  const newToken = await refreshToken();
  await agent.updateAccessToken(newToken);
});

Transcript Events

transcriptUpdate

Emitted whenever the transcript is updated (message sent or received). Use this to track all message activity in real-time.

agent.on("transcriptUpdate", (event) => {
  const { entry } = event.payload;
  
  console.log(`[${entry.direction.toUpperCase()}]`, entry.message.content);
  
  // Track sent vs received messages
  if (entry.direction === "sent") {
    console.log("User sent:", entry.message.content);
  } else {
    console.log("Agent replied:", entry.message.content);
  }
});

Payload:

Property	Type	Description
entry	TranscriptEntry	The transcript entry that was added

TranscriptEntry:

Property	Type	Description
message	Message	The message object
direction	"sent" | "received"	Message direction
timestamp	number	When the entry was added
sessionId	string | number?	Session ID
agentId	string | number?	Agent ID

Use cases:

• Building a custom chat UI that updates on every message
• Logging all conversation activity
• Analytics and message tracking
• Syncing transcript with external systems

Portal and platform events

These events support the contact center portal initialization flow and platform connectors.

initialized

Emitted when the REST initialization pipeline finishes (portal / agent / profile resolution). Payload always includes enough identity for the agent; when the CC pipeline runs, it may also include portal details, selected profile, and available lists.

agent.on("initialized", async (event) => {
  const { portal, agent, profile, availablePortals, availableProfiles } = event.payload;
  await agent.connect();
});

Payload (subset):

Property	Type	Description
portal	Portal?	Selected portal
portalDetails	any?	Raw portal details from API
agent	AgentListItem | Record<string, unknown>?	Resolved agent
profile	UserProfile?	Selected user profile
availableProfiles	UserProfile[]?	Profiles shown to the user
availablePortals	Portal[]?	Portals shown to the user

portalsAvailable

User must pick a portal. Call agent.selectPortal(portal) with one of payload.portals.

agent.on("portalsAvailable", (e) => {
  agent.selectPortal(e.payload.portals[0]); // or show a picker
});

agentsAvailable

Flow B (initParams.isDefaultAgent === "true"): user must pick an agent. Call agent.selectAgent(agent).

profilesAvailable

User must pick a profile. Call agent.selectUserProfile(profile).

Property	Type	Description
profiles	UserProfile[]	Choices
selectedPortal	Portal	Portal context

callTranscriptUpdate

Telephony call transcript (platform connector), not the WebSocket chat transcript.

Property	Type	Description
entry	CallTranscriptEntry	sender, content, timestamp

callerInfoUpdate

Property	Type	Description
callerInfo	CallerInfo	CTI fields (name, phone, email, …)

conversationIdUpdate

Property	Type	Description
conversationId	string	Platform interaction id

userContextUpdate

Property	Type	Description
userContext	Record<string, unknown>	Merged context from connector

filterTagsUpdate

Property	Type	Description
filterTags	Record<string, string[]>	Tags from onPortalSelected / connector

Event Handling Patterns

One-Time Listeners

// Handle only the first occurrence
agent.once("connected", () => {
  console.log("First connection established");
  initializeApp();
});

Removing Listeners

const handler = (event) => {
  console.log("Message:", event.payload);
};

// Add listener
agent.on("message", handler);

// Remove specific listener
agent.off("message", handler);

// Remove all listeners for event
agent.off("message");

Async Handlers

Event handlers can be async:

agent.on("agentMessage", async (event) => {
  const message = event.payload.message;
  
  // Async operations are supported
  await saveToDatabase(message);
  await updateUI(message);
});

Error Handling in Handlers

Errors in handlers are caught to prevent SDK crashes:

agent.on("message", (event) => {
  // This error won't crash the SDK
  throw new Error("Handler error");
});

// The SDK continues to work normally

TypeScript Support

All events are fully typed:

import type { AgentEvent, AgentEvents } from "@egain/ai-agent-sdk";

// Type-safe event handling
agent.on("agentMessage", (event: AgentEvent<"agentMessage">) => {
  // event.payload is fully typed
  const content = event.payload.message?.content;
});

// Custom typed handler
type MessageHandler = (event: AgentEvents["message"]) => void;

const handleMessage: MessageHandler = (event) => {
  console.log(event.payload.data);
};

Best Practices

1. Always Handle Errors

agent.on("error", (event) => {
  // Log for debugging
  console.error("SDK Error:", event.payload.error);
  
  // Report to error tracking
  errorTracker.capture(event.payload.error);
});

2. Show Connection State

agent.on("stateChanged", ({ payload }) => {
  updateConnectionIndicator(payload.state);
});

3. Use Heartbeat for UX

let typingTimeout: NodeJS.Timeout;

agent.on("heartbeat", () => {
  showTypingIndicator();
  
  clearTimeout(typingTimeout);
  typingTimeout = setTimeout(hideTypingIndicator, 2000);
});

agent.on("agentMessage", () => {
  clearTimeout(typingTimeout);
  hideTypingIndicator();
});

4. Clean Up on Unmount

// React example
useEffect(() => {
  const handleMessage = (event) => {
    setMessages(prev => [...prev, event.payload]);
  };
  
  agent.on("agentMessage", handleMessage);
  
  return () => {
    agent.off("agentMessage", handleMessage);
  };
}, []);