An agent working one Slack workspace as a bot: history, threads, posting, reactions and people.
The app must be invited to a channel before it can post there or read a private one. Nothing in the tool set searches Slack or uploads files.
What it is
An MCP server for a Slack workspace, driven by a Slack app's bot token. It includes code originally developed by Anthropic under the MIT License, with substantial modifications and new functionality added by For Good AI Inc. (dba Zencoder Inc.) under the Apache License, Version 2.0. Everything an agent does through it happens as the Slack app, not as a person.
What you get
- List the workspace's public channels, or restrict that listing to a set of channel IDs you name in advance.
- Post a message to a channel and reply inside an existing thread by its parent timestamp.
- Read recent channel history and pull the full reply chain of a thread.
- Add an emoji reaction to a specific message.
- List workspace users with basic profiles, and fetch one user's detailed profile by ID.
Requirements
A Slack app installed in your workspace with the channels:history, channels:read, chat:write, reactions:write, users:read and users.profile:read bot scopes. Its bot user OAuth token, which starts with xoxb-, goes in SLACK_BOT_TOKEN, and your workspace ID, which starts with T, goes in SLACK_TEAM_ID. SLACK_CHANNEL_IDS is optional and holds the comma-separated predefined channel list.
Setup effort
One command plus a key — npm install -g @zencoderai/slack-mcp-server, then supply credentials