[appkit plugin] [5/x] Add chat server plugin to @databricks/appkit-agent by hubertzub-db · Pull Request #387 · databricks/databricks-ai-bridge

hubertzub-db · 2026-03-20T13:58:26Z

🥞 Stacked PR

Summary

Adds a ChatPlugin to @databricks/appkit-agent, exported from the @databricks/appkit-agent/chat subpath. The plugin provides a complete chat backend: streaming responses from agent or Databricks model serving endpoints, session management, optional PostgreSQL persistence, feedback via MLflow Traces, and stream resumption.

Adapted from app-templates/e2e-chatbot-app-next](https://github.com/databricks/app-templates/tree/main/e2e-chatbot-app-next), with @databricks/appkit as a peer dependency and a standalone auth module replacing internal imports.

Usage

import { createApp } from "@databricks/appkit";
import { agent, chat } from "@databricks/appkit-agent";
import { Pool } from "pg";

const app = createApp({
  plugins: [
    agent({ /* ... */ }),
    chat({
      pool: new Pool(),       // optional — omit for ephemeral (no history)
      autoMigrate: true,      // creates ai_chatbot schema/tables on startup
      backend: "agent",       // route chat through local agent plugin
    }),
  ],
});

Demo of the chat with persistence and tools (the UI runs from existing `e2e-chatbot-app-next`)

Screen.Recording.2026-03-25.at.11.04.21.mov

What's included

ChatPlugin class extending AppKit's Plugin<ChatConfig>, registered as "chat". Exposes a chat() factory via toPlugin() and wires 13 Express routes under /api/chat/.
The plugin code is mostly copied from https://github.com/databricks/app-templates/tree/main/e2e-chatbot-app-next/server
Exposed API uses https://ai-sdk.dev/ (like the original)
Migrations are handled by drizzle-kit and enabled using autoMigrate flag

Move agent plugin source code into src/agent-plugin/ subfolder for better organization when hosting multiple plugins.

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

Add per-package pnpm-lock.yaml and CI/release workflows with explicit pnpm version and cache-dependency-path.

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

hubertzub-db · 2026-03-24T15:00:11Z

integrations/appkit-agent/src/chat-plugin/auth.ts

@@ -0,0 +1,299 @@
+/**


note: moved from https://github.com/databricks/app-templates/tree/main/e2e-chatbot-app-next/packages/auth

hubertzub-db · 2026-03-24T15:00:53Z

integrations/appkit-agent/src/chat-plugin/chat-acl.ts

@@ -0,0 +1,28 @@
+import type { ChatRow } from "./schema";


note: moved from https://github.com/databricks/app-templates/blob/main/e2e-chatbot-app-next/packages/core/src/chat-acl.ts

hubertzub-db · 2026-03-24T15:01:35Z

integrations/appkit-agent/src/chat-plugin/message-meta.ts

@@ -0,0 +1,52 @@
+const MAX_ENTRIES = 10_000;
+
+function setBounded<K, V>(map: Map<K, V>, key: K, value: V): void {


note: moved from https://github.com/databricks/app-templates/blob/main/e2e-chatbot-app-next/server/src/lib/message-meta-store.ts

hubertzub-db · 2026-03-24T15:06:09Z

integrations/appkit-agent/src/chat-plugin/persistence.ts

+
+export type { ChatRow, MessageRow };
+
+export function createDb(pool: Pool) {


note: reimplemented from https://github.com/databricks/app-templates/tree/main/e2e-chatbot-app-next/packages/db

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

This was referenced Mar 20, 2026

[appkit plugin] [2/x] Add @databricks/appkit-agent package #384

Open

[appkit plugin] [3/x] Add appkit-agent documentation #385

Open

[appkit plugin] [4/x] Add @databricks/chat-ui package #386

Open

hubertzub-db marked this pull request as draft March 20, 2026 13:59

hubertzub-db force-pushed the stack/agent-plugin-p5 branch from 28f1384 to 2d61336 Compare March 23, 2026 07:56

Agent plugin

3c23285

Move agent plugin source code into src/agent-plugin/ subfolder for better organization when hosting multiple plugins.

hubertzub-db force-pushed the stack/agent-plugin-p5 branch from 2d61336 to fa5fffc Compare March 24, 2026 10:46

hubertzub-db mentioned this pull request Mar 24, 2026

[appkit plugin] [6/x] Add bundled chat UI to @databricks/appkit-agent #391

Open

hubertzub-db force-pushed the stack/agent-plugin-p5 branch 2 times, most recently from 0a9a18e to 8a5755b Compare March 24, 2026 11:12

CR feedback

a36b8f8

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

hubertzub-db force-pushed the stack/agent-plugin-p5 branch 3 times, most recently from bceae2d to 2be31ff Compare March 24, 2026 12:11

hubertzub-db mentioned this pull request Mar 24, 2026

[appkit plugin] [7/x] Add default-ui playground for @databricks/appkit-agent #392

Open

hubertzub-db added 6 commits March 24, 2026 15:57

Responses

8c02856

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

docs

2099b65

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

CR feedback

25dfdc7

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

simple chatui

880ee12

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

Standalone pnpm for chat-ui

02d8063

Add per-package pnpm-lock.yaml and CI/release workflows with explicit pnpm version and cache-dependency-path.

Move to appkit-agent

b49eed7

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

hubertzub-db force-pushed the stack/agent-plugin-p5 branch from 2be31ff to 59b4915 Compare March 24, 2026 14:58

hubertzub-db commented Mar 24, 2026

View reviewed changes

hubertzub-db force-pushed the stack/agent-plugin-p5 branch from 1d83c9e to 61bf6ac Compare March 24, 2026 15:33

hubertzub-db changed the title ~~Add @databricks/appkit-chat-server package~~ [appkit plugin] [5/x] Add chat server plugin to @databricks/appkit-agent Mar 24, 2026

hubertzub-db requested a review from bbqiu March 24, 2026 16:02

hubertzub-db marked this pull request as ready for review March 25, 2026 08:06

Chat plugin

b074ca7

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

hubertzub-db force-pushed the stack/agent-plugin-p5 branch from 6cac4f3 to b074ca7 Compare March 25, 2026 09:24

bugfixes

ff9b66b

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

hubertzub-db force-pushed the stack/agent-plugin-p5 branch from 8bccbd3 to c469eda Compare March 25, 2026 10:11

Backend option

c4d0cb8

Signed-off-by: Hubert Zub <hubert.zub@databricks.com>

hubertzub-db force-pushed the stack/agent-plugin-p5 branch from c469eda to c4d0cb8 Compare March 25, 2026 10:38

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[appkit plugin] [5/x] Add chat server plugin to @databricks/appkit-agent#387

[appkit plugin] [5/x] Add chat server plugin to @databricks/appkit-agent#387
hubertzub-db wants to merge 11 commits intodatabricks:mainfrom
hubertzub-db:stack/agent-plugin-p5

hubertzub-db commented Mar 20, 2026 •

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		@@ -0,0 +1,52 @@
		const MAX_ENTRIES = 10_000;

		function setBounded<K, V>(map: Map<K, V>, key: K, value: V): void {


		export type { ChatRow, MessageRow };

		export function createDb(pool: Pool) {

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🥞 Stacked PR

Summary

Usage

Demo of the chat with persistence and tools (the UI runs from existing e2e-chatbot-app-next)

What's included

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hubertzub-db commented Mar 20, 2026 •

edited

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Demo of the chat with persistence and tools (the UI runs from existing `e2e-chatbot-app-next`)