• 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, and @slack/web-api@7.18.0 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.

• The Slack CLI now supports the features.agent_view app manifest property to enable the new Agent experience.

For more details about building with Block Kit, check out our Block Kit overview!

• The slack create command now accepts the --app flag to scaffold a project and automatically link it to an existing app.
• The slack external-auth add-secret command is now available to all apps, not just Slack-hosted apps.
• The Slack CLI now supports mcp_server manifest fields for connecting MCP servers to the Slackbot MCP Client.

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.

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.

For more details about building with Block Kit, check out our Block Kit overview!

• 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.

For more details about building with Block Kit, check out our Block Kit overview!

• We've added a slack api <method> command, which allows you to call any API method directly from the Slack CLI. For example:
  • slack api chat.postMessage channel=C123 text="hi"
  • slack api chat.postMessage '{"channel":"C123","text":"hi"}'
• Interactive forms are now screen reader friendly when the ACCESSIBLE environment variable is set, or when using the --accessible flag.
• We've added a new env init command to copy a template placeholder .env.sample or .env.example file to the .env file of your project.
• We've added support for the settings.is_mcp_enabled: <bool> manifest property to enable or disable the Slack MCP Server. This causes cached values to expire and the next run attempt may surface a warning noting that app settings have changed since the last update.
• We've added support for optional OAuth scopes (bot_optional and user_optional) in the app manifest schema.
• We've added a SLACK_CLI_APP_ICON_PATH environment variable to override the icon file path used during app install and local run. When set, the specified path takes priority over the manifest icon field and the default icon file search. A warning is displayed if the configured path does not exist.
• Icon auto-detection now supports .png, .jpg, .jpeg, and .gif formats in assets/ and project root. The assets/ directory is checked before project root; .png is preferred when multiple formats exist.
• App manifest display names now preserve the original app name instead of using the kebab-case directory name during slack create.
• We've added verbose debug logging and retry support to icon upload API calls.
• We capitalized "App" in the slack create category selection menu titles for more consistent title casing.
• We've added more polish to outputs from the slack create command section headers.
• The slack create command preserves path separators when a nested path is provided as the project directory. The --name flag now only overrides the app's display name in the manifest without replacing the path argument. For example:

  $ slack create path/to/my-app --name "My App"
  # Creates directory at ./path/to/my-app/ with manifest name "My App"
  

• We fixed the S3 Content-MD5 header when deploying a Deno app to Slack. We now remove the MD5 hash computation and Content-MD5 header from S3 presigned POST uploads to avoid an error.
• The Slack CLI installer now outputs the pinned version provided if a particular version is provided, rather than a version and blank space.
• The Slack CLI now avoids uploading icons for non-hosted apps that do not have the set-icon experiment enabled.

• Add reactions — adds an emoji reaction to a Slack message on behalf of the authenticated user.
• Create a conversation/channel — creates a new Slack channel, group DM, or IM conversation on behalf of the authenticated user.
• List channel members — retrieve a list of user IDs for members of a given Slack channel or conversation.
• List emoji — returns the list of custom emoji available in the workspace.
• Read files — retrieves metadata and content of files shared in Slack workspaces.

Read all about the MCP server in the API docs.

• Alert block
• Card block
• Carousel block

In addition, we've made some updates to the text-streaming API methods to support streaming blocks:

• chat.startStream
• chat.appendStream
• chat.stopStream

For more details about building with Block Kit, check out our Block Kit overview!

This version ties together iterative improvements, with special focus on agent development. The Slack CLI can now quickly scaffold an AI agent using the slack create agent command and our collection of agent sample apps. Features such as local manifest management, environment variable management, and file watching with live reloading come together to streamline the agent development experience.

New features​

Creating apps and agents​

• The AI Agent templates now include an IT support agent available with the slack create agent command.
  • Use slack create agent to choose one the new AI Agent templates:
    • Starter Agent:
      • Supports Bolt for JavaScript and Bolt for Python
      • Available in the Claude Agent SDK, OpenAI Agents SDK, and Pydantic AI framework
    • IT Support Agent:
      • Supports Bolt for JavaScript and Bolt for Python
      • Available in the Claude Agent SDK, OpenAI Agents SDK, and Pydantic AI framework
  • Slack MCP Server is built-in to all of the AI Agent templates.
• The Slack CLI installer now ends with a recommendation to run the slack create agent command.
• The slack create command now separates selections into categories of templates for frameworks to better align with the options displayed.

Managing environment variables​

• Environment variables saved to .env files are now loaded into the process before hook scripts run. This improves the slack run command, as additional dependencies are no longer required to load environment variables into the runtime context. Other commands such as the slack deploy command and the slack manifest command also benefit, as the underlying hooks can be more expressive in customizations, and can also be configured for custom environments.
• The slack env list command now lists the environment variables available from .env files for apps that aren't run on Slack infrastructure.
• The slack env set command can now add and update environment variables in .env files for apps that aren't built or run on Slack infrastructure, making configuring and iterating on a Bolt app from the command line faster.
• The slack env unset command now removes environment variables from .env files for apps that aren't built or run on Slack infrastructure.
• The slack env commands were aliased to env set and env unset to match more common shell conventions. (These commands were previously recommended as add and remove, which became confusing when existing variables were updated.) Refer to the slack env command docs for more details.

Finding docs programmatically​

• We've added a slack docs search subcommand, which can output search results using plain text, json, or your preferred browser. Refer to the slack docs command docs for more details.

Developing an app​

• We've added file watch and live reload support to slack run. This allows your Slack apps to immediately reflect changes to files by you or your agent-related development tools (Claude Code, Codex, etc.).
• It's easier to start an HTTP OAuth Server or app with a custom path, as the slack run command now accepts an optional argument for the app entry point. For example: $ slack run ./src/app_oauth.py.
• We updated the slack run command for Enterprise Organizations so that "All workspaces" is always shown as the first option when prompted to choose whether to grant to all workspaces or a specific workspace.
• When a command runs using the verbose flag (--verbose) and makes an HTTP request, the output now includes the HTTP Header's User-Agent. For example: HTTP Request User-Agent: slack-cli/v3.15.0 (os: darwin).

Python project improvements​

• The slack create and slack init commands now create a Python Virtual Environment (.venv) when it doesn't exist.
• The slack create and slack init commands now install your project dependencies from pyproject.toml and requirements.txt after activating your Python virtual environment.
• All slack commands now activate your Python virtual environment, when it exists. For example, this means slack run will activate your .venv before starting your app's server.

Bolt Framework agent improvements​

• Bolt for JavaScript 4.7.0 and Bolt for Python 1.28.0 support a collection of new agent-related UI features.
• Event listener handlers now provide utilities to display your agent's thinking status, streaming text, display suggested prompts, and more.
• The Slack MCP Server now works with Bolt Frameworks.
• Popular agent frameworks such as Claude Agent SDK, OpenAI Agents SDK, Pydantic, and Vercel now work with Bolt.

Prompt look and feel​

• We've refreshed our interactive prompt style with Charm's Huh package.
• Interactive prompts now support light-mode and dark-mode.

Bug fixes​

• We fixed a pyproject.toml error that was displayed by the slack create and slack init commands. The error occurred when creating a Bolt Python project that includes pyproject.toml, but doesn't define a [project] section or dependencies array. Now, a warning is displayed in --verbose mode, as this is a valid pyproject.toml format.
• We fixed a bug: environment variable values set for hook commands are no longer surrounded with double quotes.
• We fixed a bug with the Windows installer. The installer now suggests providing an optional alias as a separate step from downloading the installer if earlier overwrites were avoided but still caused the installation to fail.
• We fixed a bug: errors will appear sooner in CI and scripting setups if either interactive input or a confirmation is requested, rather than waiting for a timeout.
• We fixed a bug: The sections of slack env command outputs are now titled to match the command itself, and are grouped under one section for each command.

But wait, there's more!​

In version 4.0.1 of the developer tools, we've fixed the slack create agent command so that it shows prompts for the app template, Bolt Framework, and then Agent Framework. This adds more templates to the options, including Bolt for JavaScript and Bolt for Python implementations of the Starter Agent and Support Agent templates.

Previously available in early access by request only, PKCE can now be enabled directly in your app settings without contacting Slack support.

Key things to know​

• Enabling PKCE marks your app as a public client. This is a one-way operation; it cannot be undone without contacting Slack support.
• OAuth installations which redirect to a custom URI scheme (e.g. myApp://auth) will always receive rotating tokens, even if token rotation is turned off. OAuth installations issued to a standard web URL (e.g. myWebshite.com/auth) will only receive rotating tokens if the 'token rotation' setting is enabled. All refresh tokens issued to PKCE-enabled apps expire after 30 days.
• Once enabled, PKCE arguments (code_challenge, code_challenge_method, code_verifier) are optional for standard OAuth flows, but required when redirecting to a custom URI scheme.
• Desktop redirects (custom URI schemes and localhost redirects for PKCE-enabled apps) cannot request bot scopes.

Getting started​

Check out the PKCE documentation to learn how to implement the full PKCE flow, including how to generate a code_verifier, construct the authorization URL, and exchange the code using the oauth.v2.access API method without a client secret.

• The slack create command now normalizes project directory names to kebab-case (lowercase, dash-delimited, no whitespace or special characters). For example: slack create "My App" now creates a my-app directory instead of a My-App directory.
• We've updated the the slack create command's app name prompt to show the randomly generated app name as placeholder text. You can press Enter to accept the default name, or type in a new name.
• Bolt JavaScript and Bolt Python projects now default to using the local manifest.json as the app manifest (previously, it was a remote manifest from app settings). Changes to the app manifest via app settings will now be detected by the Slack CLI, and a prompt will be displayed before any manifest update action occurs (e.g., when using the slack run command). The manifest source is set after creating a new project with the slack create command or by initializing an existing project using the slack init command, and the setting is stored as "manifest.source": "local" in the .slack/config.json file.
• We've updated the slack app link command to support projects that use a manifest file as the manifest source (manifest.json). As part of this:
  • A warning message will not be displayed when the manifest source is local (project file).
  • The manifest source is not changed; it now uses the project's current manifest source.
  • The current manifest source is displayed for your reference.
  • A tip on where to change the manifest source (.slack/config.json) is displayed.
• We've also updated the app manifest overwrite warning prompt wording and appearance:
  • It now clarifies that the app settings manifest will be overwritten by the project's app manifest file.
  • It now displays a warning that changes were detected on the app settings manifest that are not in the project's app manifest file.
• We fixed a bug: we now output a warning instead of an error if activating the Python virtual environment (.venv/) fails.

What's changed:

• App configuration: Mark scopes as optional directly from the app settings page or via your app manifest using the new bot_optional and user_optional fields.
• OAuth flow: Users now see optional scopes presented separately during installation and can choose which ones to grant.
• Admin controls: Workspace admins can pre-approve which optional scopes are available to their users when approving apps.
• App manifest: Two new fields—bot_optional and user_optional—are now supported under oauth_config.scopes. See App manifest fields for details.

If your app uses scopes that aren't strictly required for core functionality, consider marking them as optional to improve installation rates. Read more on the Installing with OAuth page.

• syntax-highlighted code blocks (language-specific)
• tables
• task lists
• dividers
• variable-sized headers

Check out our rich text block and markdown block reference for more details!

• The slack create command now prompts you for a custom app name if the randomly generated default isn't your thing. This prompt appears before scaffolding a new project from a template, and when making new project directories with your custom app name, we now replace spaces with a dash (instead of removing spaces altogether) to make navigation a bit better.
• The slack create command now updates the app name in the package.json and pyproject.toml project files.
• We've updated the slack create and slack init commands to support creating a Python virtual environment (.venv) when it doesn't exist, and installing the project's dependencies from the requirements.txt and pyproject.toml project files.
• When running Slack CLI commands in a Bolt Python project, the Slack CLI will attempt to automatically activate the Python virtual environment (.venv). This allows commands that use the slack-cli-hooks Python package to run safely and successfully, even when the terminal system doesn't have the virtual environment activated.
• We've added a --subdir flag to the slack create command for extracting a subdirectory from a template repository as the project root. This supports monorepo-style templates where multiple apps live in subdirectories (e.g., slack create my-app -t org/monorepo --subdir apps/my-app).
• The slack docs command opens the slack developer docs site, and you can now use the --search flag to open the docs search page with the provided query.
• We fixed a bug and now avoid infinite loops when searching for the root project .slack directory for projects existing on drives other than the C: drive on Windows.
• We fixed a bug and now check whether an installed git command exists on Windows.