Slack by 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)

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

Using Container

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

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