Slack

The Slack server shipped in the official monorepo until late 2025 and now lives in servers-archived. It still works against current Slack bot tokens but nobody is actively patching bugs or tracking new Slack API fields. Good for internal experiments, not recommended as a production integration. What it does: - Posts, updates, and deletes messages via chat.postMessage, chat.update, chat.delete - Reads channel history with cursor pagination so long channels do not blow context - Searches messages with search.messages — this path requires a user token, not a bot token - Replies into threads and adds or removes reactions on a message - Lists channels, users, and user groups with filtering on archived state - Resolves Slack IDs to human-readable names for nicer tool output Example: Wire it into an on-call agent with SLACK_BOT_TOKEN scoped to channels:history and chat:write. The agent can summarise #incidents over the last hour and post a status thread in #status, without a human copy-pasting between tabs. Setup: SLACK_BOT_TOKEN for bot operations, optional SLACK_USER_TOKEN to enable search.messages. Required scopes: chat:write, channels:history, groups:history, and search:read for the user token. Transport: stdio only. The binary is bundled via npx so there is no global install. Notes: The server does not retry on 429 responses from Slack. If your agent is chatty, wrap the calls in client-side backoff or expect dropped messages at peak traffic. For production use the Slack Developer Platform's newer Functions API is the supported path — treat this MCP as a convenient shim rather than a strategic integration.