mcp-slack-crunchtools

Secure read-only MCP server for Slack workspaces. Provides Claude Code (and other MCP clients) with access to your Slack channels, messages, users, and files without any write permissions.

Features

Read-only: 15 tools, all read-only. Never posts, edits, or deletes anything.
Secure: 6-layer security model (input validation, token handling, client hardening, output sanitization, runtime protection, supply chain security).
User OAuth Token: Uses xoxp- tokens for user-scoped access to your workspace.
No SDK dependency: Uses httpx directly for minimal, auditable HTTP calls.

Quick Start

Using uvx (Recommended)

Terminal

claude mcp add mcp-slack-crunchtools \
    --env SLACK_USER_TOKEN=xoxp-your-token \
    -- uvx mcp-slack-crunchtools

Using Container

Terminal

claude mcp add mcp-slack-crunchtools \
    --env SLACK_USER_TOKEN=xoxp-your-token \
    -- podman run -i --rm -e SLACK_USER_TOKEN quay.io/crunchtools/mcp-slack

Local Development

Terminal

claude mcp add mcp-slack-crunchtools \
    --env SLACK_USER_TOKEN=xoxp-your-token \
    -- uv run mcp-slack-crunchtools

Setup

See CLAUDE.md for detailed instructions on creating a Slack app and obtaining a User OAuth Token.

Tools

Tool	Description
`slack_auth_test`	Test connection and get token owner info
`slack_list_channels`	List workspace channels
`slack_get_channel_info`	Get channel details
`slack_get_channel_history`	Read channel messages
`slack_get_thread_replies`	Read thread replies
`slack_list_channel_members`	List channel members
`slack_search_messages`	Search messages
`slack_get_reactions`	Get message reactions
`slack_list_reactions`	List user's reactions
`slack_list_stars`	List starred items
`slack_get_user_info`	Get user details
`slack_list_users`	List workspace members
`slack_get_user_profile`	Get user profile
`slack_list_files`	List files (metadata only)
`slack_get_file_info`	Get file metadata

Security

See SECURITY.md for the full security design document.

License

AGPL-3.0-or-later