@chat-adapter/slack

Slack adapter for Chat SDK. Configure single-workspace or multi-workspace OAuth deployments.

Installation

pnpm add @chat-adapter/slack

Single-workspace mode

For bots deployed to a single Slack workspace. The adapter auto-detects SLACK_BOT_TOKEN and SLACK_SIGNING_SECRET from environment variables:

import { Chat } from "chat";import { createSlackAdapter } from "@chat-adapter/slack";const bot = new Chat({  userName: "mybot",  adapters: {    slack: createSlackAdapter(),  },});bot.onNewMention(async (thread, message) => {  await thread.post("Hello from Slack!");});

Multi-workspace mode

For apps installed across multiple Slack workspaces via OAuth, omit botToken and provide OAuth credentials instead. The adapter resolves tokens dynamically from your state adapter using the team_id from incoming webhooks.

When you pass any auth-related config (like clientId), the adapter won't fall back to env vars for other auth fields, preventing accidental mixing of auth modes.

import { createSlackAdapter } from "@chat-adapter/slack";import { createRedisState } from "@chat-adapter/state-redis";const slackAdapter = createSlackAdapter({  clientId: process.env.SLACK_CLIENT_ID!,  clientSecret: process.env.SLACK_CLIENT_SECRET!,});const bot = new Chat({  userName: "mybot",  adapters: { slack: slackAdapter },  state: createRedisState(),});

OAuth callback

The adapter handles the full Slack OAuth V2 exchange. Point your OAuth redirect URL to a route that calls handleOAuthCallback:

import { slackAdapter } from "@/lib/bot";export async function GET(request: Request) {  const { teamId } = await slackAdapter.handleOAuthCallback(request);  return new Response(`Installed for team ${teamId}!`);}

Using the adapter outside webhooks

During webhook handling, the adapter resolves tokens automatically from team_id. Outside that context (e.g. cron jobs or background workers), use getInstallation and withBotToken:

const install = await slackAdapter.getInstallation(teamId);if (!install) throw new Error("Workspace not installed");await slackAdapter.withBotToken(install.botToken, async () => {  const thread = bot.thread("slack:C12345:1234567890.123456");  await thread.post("Hello from a cron job!");});

withBotToken uses AsyncLocalStorage under the hood, so concurrent calls with different tokens are isolated.

Removing installations

await slackAdapter.deleteInstallation(teamId);

Token encryption

Pass a base64-encoded 32-byte key as encryptionKey to encrypt bot tokens at rest using AES-256-GCM:

openssl rand -base64 32

When encryptionKey is set, setInstallation() encrypts the token before storing and getInstallation() decrypts it transparently.

Slack app setup

1. Create a Slack app from manifest

1. Go to api.slack.com/apps
2. Click Create New App then From an app manifest
3. Select your workspace and paste the following manifest:

display_information:  name: My Bot  description: A bot built with chat-sdkfeatures:  bot_user:    display_name: My Bot    always_online: trueoauth_config:  scopes:    bot:      - app_mentions:read      - channels:history      - channels:read      - chat:write      - groups:history      - groups:read      - im:history      - im:read      - mpim:history      - mpim:read      - reactions:read      - reactions:write      - users:readsettings:  event_subscriptions:    request_url: https://your-domain.com/api/webhooks/slack    bot_events:      - app_mention      - message.channels      - message.groups      - message.im      - message.mpim      - member_joined_channel      - assistant_thread_started      - assistant_thread_context_changed  interactivity:    is_enabled: true    request_url: https://your-domain.com/api/webhooks/slack  org_deploy_enabled: false  socket_mode_enabled: false  token_rotation_enabled: false

4. Replace https://your-domain.com/api/webhooks/slack with your deployed webhook URL
5. Click Create

2. Get credentials

After creating the app, go to Basic Information → App Credentials and copy:

• Signing Secret as SLACK_SIGNING_SECRET
• Client ID as SLACK_CLIENT_ID (multi-workspace only)
• Client Secret as SLACK_CLIENT_SECRET (multi-workspace only)

Single workspace: Go to OAuth & Permissions, click Install to Workspace, and copy the Bot User OAuth Token (xoxb-...) as SLACK_BOT_TOKEN.

Multi-workspace: Enable Manage Distribution under Basic Information and set up an OAuth redirect URL pointing to your callback route.

3. Configure slash commands (optional)

1. Go to Slash Commands in your app settings
2. Click Create New Command
3. Set Command (e.g., /feedback)
4. Set Request URL to https://your-domain.com/api/webhooks/slack
5. Add a description and click Save

Configuration

All options are auto-detected from environment variables when not provided. You can call createSlackAdapter() with no arguments if the env vars are set.

*signingSecret is required — either via config or SLACK_SIGNING_SECRET env var.

Environment variables

SLACK_BOT_TOKEN=xoxb-...             # Single-workspace onlySLACK_SIGNING_SECRET=...SLACK_CLIENT_ID=...                  # Multi-workspace onlySLACK_CLIENT_SECRET=...              # Multi-workspace onlySLACK_ENCRYPTION_KEY=...             # Optional, for token encryption

Features

Messaging

Rich content

Conversations

Message history

Platform-specific

Slack Assistants API

The adapter supports Slack's Assistants API for building AI-powered assistant experiences. This enables suggested prompts, status indicators, and thread titles in assistant DM threads.

Event handlers

Register handlers on the Chat instance:

bot.onAssistantThreadStarted(async (event) => {  const slack = bot.getAdapter("slack") as SlackAdapter;  await slack.setSuggestedPrompts(event.channelId, event.threadTs, [    { title: "Summarize", message: "Summarize this channel" },    { title: "Draft", message: "Help me draft a message" },  ]);});bot.onAssistantContextChanged(async (event) => {  // User navigated to a different channel with the assistant panel open});

Adapter methods

The SlackAdapter exposes these methods for the Assistants API:

Required scopes and events

Add these to your Slack app manifest for Assistants API support:

oauth_config:  scopes:    bot:      - assistant:writesettings:  event_subscriptions:    bot_events:      - assistant_thread_started      - assistant_thread_context_changed

Stream with stop blocks

When streaming in an assistant thread, you can attach Block Kit elements to the final message:

await thread.stream(textStream, {  stopBlocks: [    { type: "actions", elements: [{ type: "button", text: { type: "plain_text", text: "Retry" }, action_id: "retry" }] },  ],});

Troubleshooting

handleOAuthCallback throws "Adapter not initialized"

• Call await bot.initialize() before handleOAuthCallback() in your callback route.
• In a Next.js app, this ensures:
  • state adapter is connected
  • the Slack adapter is attached to Chat
  • installation writes succeed

const slackAdapter = bot.getAdapter("slack");await bot.initialize();await slackAdapter.handleOAuthCallback(request);

"Invalid signature" error

• Verify SLACK_SIGNING_SECRET is correct
• Check that the request timestamp is within 5 minutes (clock sync issue)

Bot not responding to messages

• Verify event subscriptions are configured
• Check that the bot has been added to the channel
• Ensure the webhook URL is correct and accessible

License

MIT