slack_list_channelsLABSCO SUMMARY
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
USE CASES
01
Report status into a channel
Send a message to a channel by ID, then keep every follow-up in its thread instead of the main feed.
02
Catch up on a discussion
Pull the most recent messages from a channel and expand the threads that matter into their full reply chains.
03
Acknowledge a request without adding a message
React to one message, addressed by its timestamp, with an emoji name.
04
Work out who is in a conversation
List workspace users to map IDs to names, then read one person's detailed profile.
05
Find the channel to write to
Page through the workspace's channels to get the IDs every other tool takes as input.
8 tools
Listed in project docs. Your client may show a different list.
slack_post_messageslack_reply_to_threadslack_add_reactionslack_get_channel_historyslack_get_thread_repliesslack_get_usersslack_get_user_profileBEFORE YOU INSTALL
What to know first
Tools you get
8 tools named in the project's documentation.
Requires
- a Slack app in your workspace with the six documented bot scopes
- SLACK_BOT_TOKEN in your environment
- SLACK_TEAM_ID in your environment
INSTALLATION
Connect your client
This project publishes no client configuration, so the entry for your client is yours to write.
Server setup
TERMINAL
npm install -g @zencoderai/slack-mcp-serverInstalls the slack-mcp command. Your client's entry runs slack-mcp (stdio is the default transport) and needs SLACK_BOT_TOKEN (the bot token, starting xoxb-) and SLACK_TEAM_ID (your workspace ID, starting T) in its environment; SLACK_CHANNEL_IDS is optional. A Docker image, zencoderai/slack-mcp, is also documented.
