diff --git a/js/ai/src/chat.ts b/js/ai/src/chat.ts
index f22b351ba..e84131057 100644
--- a/js/ai/src/chat.ts
+++ b/js/ai/src/chat.ts
@@ -33,7 +33,7 @@ import {
   Session,
   SessionStore,
   runWithSession,
-} from './session';
+} from './session.js';
 
 export const MAIN_THREAD = 'main';
 
@@ -242,7 +242,7 @@ export class Chat {
     return this._messages ?? [];
   }
 
-  async updateMessages(messages: MessageData[]): Promise<void> {
+  private async updateMessages(messages: MessageData[]): Promise<void> {
     this._messages = messages;
     await this.session.updateMessages(this.threadName, messages);
   }
diff --git a/js/ai/src/session.ts b/js/ai/src/session.ts
index 2d5af2fd9..2e7f0cf6d 100644
--- a/js/ai/src/session.ts
+++ b/js/ai/src/session.ts
@@ -17,7 +17,7 @@
 import { z } from '@genkit-ai/core';
 import { Registry } from '@genkit-ai/core/registry';
 import { v4 as uuidv4 } from 'uuid';
-import { Chat, ChatOptions, MAIN_THREAD, PromptRenderOptions } from './chat';
+import { Chat, ChatOptions, MAIN_THREAD, PromptRenderOptions } from './chat.js';
 import {
   ExecutablePrompt,
   GenerateOptions,
diff --git a/js/genkit/src/index.ts b/js/genkit/src/index.ts
index 723dee1fb..62f27c242 100644
--- a/js/genkit/src/index.ts
+++ b/js/genkit/src/index.ts
@@ -104,7 +104,12 @@ export {
   type ToolRequestPart,
   type ToolResponsePart,
 } from '@genkit-ai/ai';
-export { type SessionData, type SessionStore } from '@genkit-ai/ai/session';
+export { Chat } from '@genkit-ai/ai/chat';
+export {
+  Session,
+  type SessionData,
+  type SessionStore,
+} from '@genkit-ai/ai/session';
 export {
   FlowServer,
   GENKIT_CLIENT_HEADER,