slackxmcp

slackxmcp is an open-source Slack stdio MCP server built on top of the official @slack/bolt, @slack/web-api, commander, and @modelcontextprotocol/sdk.

It lets MCP-compatible clients interact with Slack through Web API tools and optionally subscribe to inbound Slack messages through a Socket Mode powered MCP notification channel.

Highlights

• Exposes Slack as an MCP server over stdio.
• Uses Slack Bolt Socket Mode for inbound event delivery.
• Uses the official Slack Web API client for reads and writes.
• Supports interactive configuration via slackxmcp configure.
• Provides tools for identity, status, conversation lookups, history, thread replies, and common message mutations.
• Can emit incoming Slack message events over an optional MCP notification channel.

Requirements

• Node.js 24+
• A Slack app with Socket Mode enabled

Slack App Setup

At minimum, configure:

• Socket Mode enabled with an app token that has connections:write
• Token scopes for whichever Slack token you use:
  • channels:read
  • groups:read
  • im:read
  • mpim:read
  • channels:history
  • groups:history
  • im:history
  • mpim:history
  • chat:write
  • reactions:write
  • users:read
• Event subscriptions for the message surfaces you care about, such as:
  • message.channels
  • message.groups
  • message.im
  • message.mpim

Depending on your workspace policy and the conversations you target, Slack may require additional scopes.

If you want to use slack_search_messages, you will typically also need a user token with search:read because Slack does not expose message search through bot tokens.

Installation

Use it without installing globally:

npx slackxmcp mcp

Or for local development:

npm install
npm run build
npm run dev -- mcp

Quick Start

1. Run the interactive configuration:

slackxmcp configure

This writes:

~/.slackxmcp/config.json

2. Start the MCP server:

npx slackxmcp mcp

3. If your MCP host supports notifications and you want inbound Slack events, enable channels:

npx slackxmcp mcp --channels

The server uses stdio, so it is meant to be launched by an MCP client or wrapper rather than browsed directly in a terminal.

CLI Usage

MCP Server

npx slackxmcp mcp

Starts the stdio MCP server for the configured Slack app.

Configure

npx slackxmcp configure

Then opens an interactive configure UI (Ink) to manage:

• App token
• Bot token
• User token
• Allowed users
• Allowed channels

Allowlist items are toggled from menu screens (select an entry to toggle it, then choose Back).

Allowed users/channels screens support live type-to-filter search with a 5-row scroll viewport for faster selection in large workspaces.

Everything is persisted to:

~/.slackxmcp/config.json

MCP Tools

The server currently exposes these tools:

• slack_get_me
• slack_get_status
• slack_get_channel
• slack_get_channel_members
• slack_list_channels
• slack_list_users
• slack_search_messages
• slack_get_channel_history
• slack_get_thread_replies
• slack_send_message
• slack_send_files
• slack_reply_to_message
• slack_react_to_message
• slack_edit_message
• slack_delete_message

Push Channel

When started with --channels, the server:

• advertises the experimental MCP capability hooman/channel
• advertises hooman/user with path meta.user
• advertises hooman/session with path meta.session
• advertises hooman/thread with path meta.thread
• advertises hooman/channel/permission for remote daemon approvals
• emits notifications/hooman/channel for inbound Slack message events

If allowlist entries are configured, notifications/hooman/channel events are emitted only when either:

• meta.session (conversation ID) is in allowlist.channels, or
• meta.user (sender user ID) is in allowlist.users

When no allowlist is configured (or both arrays are empty), all inbound channel events are emitted.

Each notification includes:

• content: a JSON-encoded event payload
• meta.source: always slack
• meta.user: the Slack sender ID when available
• meta.session: the Slack conversation ID
• meta.thread: the Slack thread timestamp, or the message timestamp for non-threaded messages

The JSON-decoded content payload includes:

• source
• self
• message
• text

Inbound notification messages ignore Slack bot/system message subtypes.

When Hooman sends notifications/hooman/channel/permission_request, slackxmcp posts the request back into the originating Slack conversation/thread with Block Kit action buttons derived from params.options (defaults: allow once, always allow, deny). Tapping a button is relayed back over notifications/hooman/channel/permission. There is no text-command approval path; the Slack app must have Interactivity enabled so Bolt can receive block_actions over Socket Mode.

License

See LICENSE file.