@modelcontextprotocol/server-slack
Anthropic's official reference MCP server for Slack. Gives agents the ability to read and send messages in Slack channels, list users, and interact with the Slack workspace.
Score Breakdown
⚙ Agent Friendliness
🔒 Security
Bot token scopes allow fine-grained permission control. Token via env var. Slack's enterprise features (EKM) available for regulated industries. Bot token exposure gives access to all channels the bot is in — rotate immediately if compromised.
⚡ Reliability
Best When
Your agent needs to communicate via Slack — post messages, read channel history, list users. Official reference implementation with clean tool definitions.
Avoid When
You need real-time event handling (use Slack Events API with webhooks) or complex Slack app features (modals, home tabs, interactive components).
Use Cases
- • Agents posting updates, reports, or alerts to Slack channels automatically
- • Reading Slack channels for context before taking actions in other systems
- • Building AI-powered Slack bots that respond to messages in channels
- • Triaging Slack messages and routing to appropriate teams or tickets
- • Summarizing Slack conversation history for absent team members
Not For
- • Direct message (DM) monitoring without explicit user consent
- • Slack Enterprise Grid features (workspace federation, org-wide settings)
- • High-frequency message polling (use Slack Events API with webhooks instead)
Interface
Authentication
Slack Bot Token required (xoxb-...). Create a Slack App at api.slack.com/apps, add bot token scopes (channels:read, chat:write, users:read, etc.), install to workspace. Set SLACK_BOT_TOKEN env var.
Pricing
MCP server is MIT licensed/free. Slack API is free for most operations. Rate limits: Tier 1 (1 req/min), Tier 2 (20 req/min), Tier 3 (50 req/min). Slack Paid plans may unlock additional API features.
Agent Metadata
Known Gotchas
- ⚠ Bot must be added to each channel before it can read/post — agents often fail silently on channels they aren't in
- ⚠ Rate limits are per-method-per-workspace — agents calling the same endpoint repeatedly will be throttled
- ⚠ Message history limited by Slack plan (free plans have 90-day history limit)
- ⚠ Thread replies require separate API call — reading a channel doesn't include thread replies
- ⚠ Slack user IDs (U12345) differ from display names — agents must look up names explicitly
- ⚠ Posting as bot shows bot name/avatar — users can't tell which human triggered it without explicit attribution
Alternatives
Full Evaluation Report
Detailed scoring breakdown, competitive positioning, security analysis, and improvement recommendations for @modelcontextprotocol/server-slack.
Scores are editorial opinions as of 2026-03-06.