Slack MCP Server
github.com/korotovsky/slack-mcp-server- Category
- Developer Tools
- Rank
- No. 437Tools index
- Listed in
- #7 Connect tools with MCP
- Pricing
- Free
- Type
- TOOL
- Builder
- korotovsky
- GitHub
- 1.8k stars
- Latest release
- v1.3.0
- Added
- Jul 4, 2026
About
A powerful Slack MCP server that connects an agent to Slack with no admin permissions required — read channels and DMs, post messages, and fetch smart history — supporting stdio and SSE transports, including GovSlack.
What it does
It gives AI agents structured Slack operations beyond basic chat access. Agents can search conversations, inspect threads and unread items, resolve users and channels, manage reactions, retrieve attachments, work with user groups, and process saved items. Results commonly use compact CSV for easier model consumption.
Why it's ranked here
The scope is unusually practical for workplace research and triage. Safety controls keep message posting, reactions, and attachment retrieval off by default, while caching, pagination, proactive throttling, and retry handling address common production failure modes. The included tests cover tool selection and rate-limit behavior.
What's good
Channel names and user handles can replace opaque identifiers in common requests. History accepts either time windows or message counts, and search offers channel, participant, date, and thread filters. Unread sorting prioritizes direct messages and partner channels. Write access can be restricted to selected channels. The server also annotates read-only and destructive operations for compatible clients.
Tradeoffs
Message search does not work with bot tokens because Slack denies that API capability. Browser-session and OAuth credentials expose different user-search behavior. Cached users and channels may be temporarily unavailable during synchronization. Attachment retrieval requires explicit activation and caps files at five megabytes. Several useful actions therefore depend on credential choice and deliberate configuration.
How to use it well
Use it for an agent that summarizes channel activity, investigates past decisions, triages unread conversations, or manages saved Slack work under human supervision. Start read-only, then allow posting or reactions only in approved channels. It fits Slack-centered workflows, but it does not supply cross-application automation or independent workflow orchestration.
Technical notes+
The module in go.mod targets Go 1.25 and uses github.com/mark3labs/mcp-go. pkg/server/server.go declares 22 valid MCP tools, applies recovery, logging, and transport authentication middleware, and attaches read-only or destructive annotations where appropriate. pkg/provider/api.go stores immutable user and channel cache snapshots through atomic pointers, namespaces cache files by workspace team ID, and writes cache data through temporary-file renames. pkg/limiter/retry.go combines proactive rate limiting with caller-classified retries and context cancellation. Makefile builds native binaries for Darwin, Linux, and Windows on amd64 and arm64, then packages them for npm and DXT distribution. pkg/server/server_test.go and pkg/limiter/retry_test.go exercise tool gating, validation, retries, and cancellation.
Observed
- Primary language
- Go, with the module targeting Go 1.25.
- Interface
- Model Context Protocol server with stdio, SSE, and HTTP transports.
- Packaging
- Native binaries, npm packages, and a DXT extension are built by repository targets.
- Platform support
- Build targets cover Darwin, Linux, and Windows on amd64 and arm64.
- Tool surface
- The server declares 22 valid MCP tools spanning conversations, channels, users, reactions, attachments, user groups, and saved items.
- Testing
- Go tests cover server tool gating and validation, saved-item formatting, and rate-limiter retry behavior.
Read from README.md, go.mod, Makefile, pkg/provider/api.go, pkg/server/server.go, pkg/handler/saved.go, pkg/limiter/retry.go, pkg/limiter/limits.go, pkg/version/version.go, pkg/handler/channels.go, pkg/handler/saved_test.go, pkg/handler/usergroups.go, pkg/limiter/retry_test.go, pkg/server/server_test.go.
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Indexed by a proprietary survey. Corrections welcome.