Slack Developer Updates & Release Notes

Slack Code enables even more collaboration between humans and agents in Slack by creating dedicated channels for deeper work. Agents can now create ephemeral channels from existing conversations, providing agents and their human collaborators a shared, visible place to work.

Your agents manage the space: create a new code channel when a user’s request entails more work than a quick reply, and add bookmarks and artifacts so users can see your agent’s work. As the work progresses, your agent can post updates and convey status, and even archive the channel when work is complete.

Read on to learn more:

• Slack Code
• Code channels lifecycle
• Agent slash commands
• Code channel properties

Version 4.9.0 of the Slack CLI is here!

• We've added support for the settings.app_level_token_rotation_enabled app manifest property, which opts your app in to rotating app-level tokens.
• We fixed an issue where an expired login with an invalid refresh token caused the CLI to retry token rotation on every command. The CLI now asks you to run slack login again.
• We fixed an issue where the slack activity --tail and slack run commands kept requesting activity logs after the login token became invalid. The command now exits with the auth error.

We're rolling out a wave of updates to agents on Slack, along with an important heads-up about the road ahead for the Assistant messaging experience.

Agent updates and the deprecation of assistant_view​

The Assistant messaging experience (assistant_view) will be deprecated in February 2027. The assistant-related methods that power it are being replaced by a new set of API methods: the Agent Sessions API. Agent sessions let users manage their conversations with your agent in one place, with a status, a title, and a stop button. The agents.sessions.setStatus and agents.sessions.rename API methods replace the assistant.threads.setStatus and assistant.threads.setTitle API methods, respectively. For now, your existing calls keep working through a compatibility bridge. See the Agent sessions guide to get started. …

An agent can answer a question in a thread, but some tasks become bigger than a single question. A coding agent may need to implement a change, share a prototype, and iterate on it. A research agent may need to gather information and work through decisions with the people involved. This kind of work needs more than a single response.

Slack Code is how agents and people work together to build with AI in Slack, creating dedicated channels for more involved work. A channel is created from an existing conversation, context is carried forward, and agents and collaborators have a shared, visible place to work.

Within a session, agents can publish artifacts for people to oversee and iterate on:

• Code diffs, so people can review what changed
• Block Kit views, for structured interactive experiences
• HTML previews, for prototypes and generated interfaces
• Canvases, for longer-form content and collaboration

The work becomes multiplayer: teammates can join channels, review work, add context, and help make decisions, all while collaborating in the same session and with the same artifacts. Your agent manages the lifecycle, creating a channel when a task warrants one, sharing updates as the work progresses, and closing the session once the work is complete.

Read on to learn more:

• Slack Code: where your team and agents build together …

We're excited to introduce the Slack MCP and Skills Plugin for AI tools, which bundles a set of skills that help you develop on the Slack platform alongside the Slack MCP Server. The plugin is currently available for Claude Code and Cursor.

Installing the plugin sets up two things:

• Skills. Focused sets of instructions and references that your assistant loads automatically when a task calls for them. The plugin includes skills for Block Kit, scaffolding new apps, calling Web API methods, using the Slack CLI, composing messages, and searching Slack.
• Slack MCP Server connection. The Slack MCP server lets you and your agent interact directly with your Slack workspace, such as searching channels, sending messages, and managing canvases.

Install the plugin in Claude Code with /plugin install slack@claude-plugins-official, or from the Cursor Marketplace.

Read the Slack MCP and Skills Plugin docs to get started.

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.