Slack Developer Updates & Release Notes

Version 4.11.0 of the Slack CLI is here!

We've made password-free sign-in the default for the slack sandbox create command. If you don't pass the --password flag, you sign in to the new sandbox with a link sent to your email.

We've added support for the features.user_connections app manifest property (is_enabled and auth_hosts), so the slack run, slack deploy, and slack manifest sync commands keep it.

We've updated the CLI to Go 1.27.3, which no longer trusts the compromised eMudhra certificate authorities.

We've raised the supported Deno version for local development to 2.9.8, the first release that no longer trusts the compromised eMudhra certificate authorities. The slack doctor command now reports older Deno versions as unsupported, so upgrade your local Deno to 2.9.8 or later.

All new deploys and re-deploys to Run on Slack infrastructure now use Deno 2.9.8, which no longer trusts the compromised eMudhra certificate authorities.

We fixed an issue where the restricted_scopes error shown when installing an app did not explain the cause. The error now says which kinds of scopes need an admin or owner to install, and how to resolve it.

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've added support for the TaskCardBlock layout block (task_card type) and related fields, as well as UrlSourceElement for the sources field.

We've added support for the ContainerBlock layout block (container type) and related fields.

We've added support for the following Slack Code API methods:

• agents.conversations.archive
• agents.conversations.create
• agents.conversations.getCanvas
• agents.conversations.listViews
• agents.conversations.removeView
• agents.conversations.setCanvasContent
• agents.conversations.setCommands
• agents.conversations.setProperties
• agents.conversations.setView

We've added support for the ContainerBlock layout block (container type) and related fields.

The TableBlock model in slack_sdk.models.blocks now allows allow raw_number cells.

We've added support for the following Slack Code API methods:

• agents.conversations.archive
• agents.conversations.create
• agents.conversations.getCanvas
• agents.conversations.listViews
• agents.conversations.removeView
• agents.conversations.setCanvasContent
• agents.conversations.setCommands
• agents.conversations.setProperties
• agents.conversations.setView

We've released the following Node SDK-related updates:

Socket Mode v3.1.0

The default dispatcher now pins the WebSocket connection to HTTP/1.1, since undici@^8 offers HTTP/2 by default. To do the same with a custom ProxyAgent dispatcher, pass requestTls: { allowH2: false }.

Types v3.2.0

We added the ContainerBlock block interface.

We added the data_table Block Kit block type (DataTableBlock).

We now allow raw_number cells in TableBlock rows (adds RawNumberElement).

We added an optional action_id property to the WorkflowButton block element.

Web API v8.2.0

We added the agents.conversations.* methods for Slack Code:

• create,
• archive,
• setProperties,
• setView,
• setCommands,
• listViews,
• removeView,
• getCanvas,
• setCanvasContent

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.

The Agent messaging experience (agent_view) is already available, and we recommend moving to it now. If your app still uses assistant_view, follow the migration guide to move to the new experience. Read more in the guide to developing agents.

What's new for agents​

Alongside this announcement, we're releasing a set of improvements to the agent experience:

• Upgraded Tools tab: a newly renamed and revamped Agents & Tools tab helps users find popular agents with a new landing page.
• Improved thread experience: including multi-agent stacking, thread naming, a revamped thinking UI, and a native stop button for agent streams. When a user stops your agent, your app receives an agent_session_stopped event.
• Plan and Task card block updates: UI refinements to the plan and task card blocks agents use to show their work.
• Marketplace data in the About tab: an agent's Marketplace data now appears in its About tab.
• Agent sessions in the sidebar: A new sidebar with pin / archive / unread and live updates.

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
• Build with AI as a team using Slack Code

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.