Slack MCP Server is a Model Context Protocol (MCP) server for Slack workspaces. The implementation supports Stdio, SSE, and HTTP transports, enabling MCP clients to connect in diverse environments, and it can route outgoing requests through a proxy. It can operate in stealth mode, avoiding additional permissions or bot installations, or in OAuth mode using secure tokens for access without needing to refresh or extract tokens from the browser. It provides Enterprise Workspaces support for integration with large Slack deployments. The server offers channel and thread access with name-based lookups (e.g., #general) or IDs, including activity messages, and supports Direct Messages (DMs) and group Direct Messages (Group DMs). Smart History provides pagination by date or message count; Search Messages allows filtering across channels, threads, and DMs by date, user, and content. Safety is enforced by disabling the conversations_add_message tool by default; it can be enabled via an environment variable, with optional channel restrictions. The server embeds user information in messages and caches users and channels for faster startup, and exposes workspace directories via slack:// URIs for channels and users.