What it does
The Slack MCP Server connects Claude to your Slack workspace, enabling message retrieval from channels, threads, and direct messages, plus optional message posting. It supports two operational modes: a stealth mode that requires no bot installations or workspace permissions, and an OAuth mode using secure tokens. The server handles message pagination by date ranges or message count, unread message aggregation with priority sorting, full-text search across conversations, and optional user information embedding for richer context.
Who it's for
Slack workspace administrators and knowledge workers who want Claude to access conversation history for analysis, summarization, or informed decision-making. Teams running Claude-integrated workflows that need to draw context from Slack channels or threads without requiring bot approvals.
Common use cases
- Retrieve recent messages from a Slack channel (e.g., #general or #support) to provide Claude with current team context
- Fetch all replies in a thread to analyze a specific discussion or decision
- Search messages across your workspace to find information by date, user, or keyword
- Retrieve unread messages across channels to brief Claude on what's happened since last check
- Post Claude's analysis or decisions back to a specific Slack channel (when enabled via environment variable)
Setup pitfalls
- Message posting is disabled by default for safety. Set
SLACK_MCP_ADD_MESSAGE_TOOLto enable, optionally restricting to specific channels via comma-separated IDs. - Choose between stealth mode (no bot/permissions required) or OAuth mode (requires token); both require valid workspace access and user authentication.
- The server lacks automated testing infrastructure (no CI configured), so verify it works in your environment before relying on it for critical workflows.
- Runs with medium risk classification; ensure it has network access only to Slack and runs in a trusted context with appropriate API key/token protection.