Slack Developer Updates & Release Notes

Version 4.5.0 of the developer tools for the Slack platform has landed!

The Slack CLI now recommends the official Slack plugin to Claude Code users.

We've reduced the verbose output when using create --app to link an existing app during project creation.

We've added a --category flag to slack docs search command.

When the CLI errors because a prompt must be shown while in a non-TTY environment (AI agents, devops scripts, etc.), the error message now displays the prompt and, for app and team selection, the matching flags to select an option.

We've fixed a recurring unable_to_parse_json error caused by empty JSON files (credentials, config, or app state) left behind by an interrupted write; the CLI now treats them as empty state and recovers automatically.

Version 5.0.0 of Bolt for JS is here! This release follows the Node Slack SDK's shift from axios to the native Fetch API, removes the deprecated Workflow Steps from Apps feature, and raises the minimum Node.js version to 20.

If your app doesn't use proxy/TLS configuration or inspect respond() return values, this upgrade is possibly only a version bump.

New features

We've added a dispatcher option to the SocketModeReceiver class.

We've added instanceof operator support to error classes.

Breaking changes

We've raised the minimum Node.js version to 20.

We've removed the agent and clientTls options from the AppOptions interface.

We've updated the SocketModeReceiver class to accept a dispatcher option instead of proxy agents.

We've removed Workflow Steps from Apps.

We've updated the respond() utility function to return a native Response object.

We've upgraded the Node Slack SDK dependencies.

We've improved error handling throughout.

For full migration details, see the Bolt for JS v4 to v5 migration guide.

Our collection of Node Slack SDK packages have received new major versions.

All packages now require Node.js 20 or later. This is the only breaking change for the following packages:

• The cli-hooks package has been updated to v2.
• The cli-test package has been updated to v4.
• The logger package has been updated to v5.
• The oauth package has been updated to v4.
• The types package has been updated to v3.

Three packages have more substantial breaking changes:

• The socket-mode package has been updated to v3. See the guide on migrating @slack/socket-mode from v2 to v3 for handling breaking changes.
• The web-api package has been updated to v8. See the guide on migrating @slack/web-api from v7 to v8 for handling breaking changes.
• The webhook package has been updated to v8. See the guide on migrating @slack/webhook from v7 to v8 for handling breaking changes.

Most of the changes in those batch of updates fall under the theme of HTTP transport improvements, such as migrating from axios to the native Fetch API.

Agent apps can now receive context about what a user is currently viewing when they send a message. When a user has a channel, DM, thread, canvas, or list open and messages your app, Slack will pass that context automatically.

Here's what developers need to know:

New event: app_context_changed

Slack will send an app_context_changed event to your app whenever the user's active context changes. The event payload includes an ordered list of entities the user is currently viewing.

The app_context is now sent to message.im and app_home_opened events

Slack will also send the app_context to these events if the app is subscribed to the app_context_changed event.

Learn more in the guide to Developing agents.

Agents now support a new messaging experience, set by your app manifest:

Agent messaging experience (agent_view)

agent conversations now look & feel the same as a regular direct message. Gone is the history tab and new chat button. Instead, all of your conversations appear in the standard message tab and your agent can respond in-thread.

Assistant messaging experience (assistant_view)

agent conversations happen in separate Chat and History tabs.

New apps can only use the Agent messaging experience. Apps that already use the Assistant messaging experience can continue to use it for now, but assistant_view will eventually be deprecated, and we'll ask existing apps to migrate to agent_view.

The Agent messaging experience changes the following:

• Knowing when a user opens a DM: rely on the app_home_opened event to know when a user has actively opened a DM with your app. The assistant_thread_started event no longer indicates this. See Developing an agent for details.
• Suggested prompts: suggested prompts now live at the top of the Messages tab instead of within threads, and the thread_ts argument is no longer required when agent_view is enabled.
• Continuing a conversation: after a user sends a new message, calling the assistant.threads.setStatus API method on that thread automatically opens the thread to keep the conversation going.

The Slack CLI v4.4.0, Python SDK v3.43.0 with Bolt Python v1.29.0, and @slack/[email protected] (for the Node Slack SDK) are required to access the Agent View feature.

Already have an app using the Assistant messaging experience? Follow the migration checklist to move to the Agent messaging experience. Read more in the guide to developing agents.

We're excited to introduce you to the Slackbot MCP Client, which gives you the ability to superpower Slackbot with your desired tools.

The Slackbot MCP Client allows developers to connect MCP servers to Slack. Once connected, Slackbot will automatically discover your MCP server's tools and invoke them based on user prompts in conversation.

Four authentication methods are available for connecting to MCP servers:

• Slack identity auth: for MCP servers that map Slack user and team IDs to available features, with no separate OAuth flow required for end users.
• No auth: for MCP servers that serve standard responses regardless of requestor.
• Dynamic Client Registration: for MCP servers that support standard OAuth discovery. Slack handles client registration automatically.
• Manual OAuth: for MCP servers where you manually register OAuth credentials with the provider.

Read the Slackbot MCP Client docs to get started.

Slack system notifications (such as channel membership changes, User Group updates, Slack Connect alerts, and retention policy notices) are now delivered from the "Slack" system user (USLACK) instead of Slackbot.

What's changing

Previously, system-generated notifications were sent as direct messages from Slackbot. Now that Slackbot is the home for AI conversations in Slack, we want to separate notification delivery for clarity. These notifications are now sent from the new "Slack" system user, USLACK. Existing historical Slackbot system notifications will be backfilled and moved to the new "Slack" DM as well.

Note: User-authored messages sent directly to Slackbot (e.g., messages you typed into the Slackbot conversation) are not affected by this change.

What this means for developers

If your app or integration:

• Filters incoming messages or events by Slackbot's user ID,
• Checks the username field for "Slackbot" to identify system notifications, or
• Uses the chat.postMessage API method or related API methods and expects system notifications to route through Slackbot

then you should update your integration to handle the new "Slack" system user (USLACK) instead.

No action required if your integration does not reference Slackbot's user ID or username in its logic.

Version 4.2.0 of the Slack CLI has arrived!

The slack api command can now send unauthenticated requests when no token is available or when --no-auth is specified.

The slack api command no longer triggers a background update check when invoked with arguments (e.g., slack api chat.postMessage).

Any Y/N select prompts now display as vertical selection, similar to the slack create command.

We've disabled upgrade notifications for the slack manifest and slack manifest info command. The command returns JSON that may be used for scripting, and the notifications interfere with parsing the response output.